Alan Aragon’s Research Review, February, 2008                                  [Back to Contents]                  Page 1 

Copyright © February 1st, 2008 by Alan Aragon Home: www.alanaragon.com/researchreview Correspondence: aarrsupport@gmail.com

2 Nutrient Timing, Part 2:

Pre- & During Exercise Carbohydrate & Protein 9 Carbohydrate-Protein Drinks Do Not Enhance Recovery

From Exercise-Induced Muscle Injury. Green MS, et al. Int J Sport Nutr Exerc Metab. 2008

Feb;18(1):608-23. [IJSNEM] 10 Effect of dietary protein content during recovery

from high-intensity cycling on subsequent performance and markers of stress, inflammation, and muscle damage in well-trained men. Rowlands DS, et al. Appl Physiol Nutr Metab. 2008 Feb;33(1): 39–51 [APNM]

11 Effects of a supplement designed to increase ATP

levels on muscle strength, power output, and endurance. Herda TJ, et al. J Int Soc Sports Nutr. 2008 Jan 29;5(3) [JISSN]

12 One-year ad libitum consumption of diacylglycerol oil as part of a regular diet results in modest weight loss in comparison with consumption of a triacylglycerol control oil in overweight Japanese subjects. J Am Diet Assoc. 2008 Jan;108(1):57-66. [Medline]

13 Metabolic and performance effects of raisins versus

sports gel as pre-exercise feedings in cyclists. Kern M, et al. J Strength Cond Res. 2007 Nov 1;21(4):1204-1207. [Medline]

14 Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial. Das SK, et al. Am J Clin Nutr. 2007 Apr;85(4):1023-30. [Medline]

15 Master Amino Acid Pattern (MAP) provides a sure

way to rebuild energy – fitness – life! [BodyHealth]

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Nutrient Timing, Part 2: Pre- & During Exercise Carbohydrate & Protein By Alan Aragon INTRODUCTION The above boxed section was previously stated in last month’s issue. I’m carrying it over to the present issue because it’s important to maintain that perspective as we go through what amounts to an exercise in micro-management. Last month we saw that when it comes to nutrient timing effects, fat generally is a minor contributor. And in the case of endurance performance, it can potentially be detrimental (particularly in the case of MCT) taken pre- or during endurance training. In this issue, we’ll take a look at protein and carbohydrate together, since they work interactively within the context of nutrient timing relative to exercise. Another thing that needs elucidating is that nutrient timing is of little use to obese folks who just want to break into a normal bodyfat range. For the latter population it’s all about maintaining a calorie deficit, and re-opening that deficit when equilibrium is reached. Nutrient timing has more measurable (and obviously more acute) effects when it’s used for exercise performance than when it’s used for altering body composition. This is especially the case with endurance training – which leads us back to the fact that most nutrient timing research is focused on improving endurance. As for the misunderstood & misguided practice of slow and/or fasted training in attempt to hurry up fat loss, I go into depth on both topics here and here. Assuming you’ve read last month’s issue, it bears repeating that the vast majority of nutrient timing research has centered on carbohydrate. Nutrient timing for strength/power training, as well as protein timing in general, is still preliminary and scarce, but we’ll examine the little there is.

PRE-EXERCISE Although endurance training can refer to a wide range of modes and intensities of exercise, let’s define it for our purposes as any continuous cardio-respiratory-focused activity that exceeds 60 minutes. The objectives of pre-exercise endurance nutrition are to maintain sufficient levels of hydration, blood glucose, and amino acids. The most measurable reasons behind these objectives are to “spare” or reduce glycogen breakdown, prevent muscle protein breakdown, and promote muscle protein synthesis. The latter effects over time can result in beneficial adaptations in both body composition and performance. These same objectives apply to strength/power training, which we’ll define as activity involving intermittent sets of short-term near-maximal efforts (and beyond) using external loads – i.e., the various incarnations of weight training. I’ll interchange this with “resistance training”, since this is the way it’s commonly stated in the literature.

HIERARCHY OF IMPORTANCE (REITERATED) When speaking of nutrition for improving body composition or athletic performance, it’s crucial to realize there’s an underlying hierarchy of importance. At the top of the hierarchy of effects is total amount of the macronutrients by the end of the day. Below that – and I mean distantly below that – is the precise timing of those nutrients. With very few exceptions (i.e., the intermittent fasting crowd), athletes and active individuals eat multiple times per day, to the tune of at least four meals. Thus, the majority of their day is spent in the postprandial (fed) rather than a post-absorptive (fasted) state. The vast majority of nutrient timing studies have been done on overnight-fasted subjects, which obviously limits the applicability of the studies’ conclusions. Pre-exercise (and/or during-exercise) nutrient intake often has a lingering carry-over effect into the during- and post-exercise period. Throughout the day, there’s a constant overlap of meal absorption. For this reason, nutrient timing is not a strategy that’s only effective if done with chronometer-like precision.

Carbohydrate Loading Days Before Competition Carbohydrate loading is a technique used to cause above-normal glycogen storage, which is also referred to as glycogen supercompensation. The classic carbohydrate loading model involves 3-4 days of glycogen depletion (60-100g/day) coupled with exhaustive exercise, followed by 3-4 days of carb-loading (500-600g/day) and reducing training volume.1 This has resulted in performance enhancement by increasing time to exhaustion. However, this protocol isn’t free of adverse potential. A low carbohydrate intake similar to the depletion phase was observed to detrimentally impact mood in trained female endurance athletes.2 Interestingly, no alterations in mood were seen in men undergoing a glycogen-depleting experiment that more closely resembled a classic carb-loading protocol (except the low & high carb phases were in reverse order).3 To avoid the potential pitfalls of depletion phases, more linear carbohydrate elevations have been investigated in various trials (10-12.5g/kg, 1-7 days prior to testing), showing glycogen supercompensation levels comparable to the classic model. It’s important to keep in mind that carb loading increases endurance capacity, rather than exercise performance per se. In other words, it can prolong the duration of exercise before fatigue hits, but it can’t necessarily reduce the amount of time it takes to perform a given amount of work, nor can it reliably increase the total work output within a given time period. For this reason, carb-loading might not be a critical strategy for enhancing endurance in competition lasting less than 90 minutes.4,5

However, it’s still not all that simple. The effect of increased glycogen on single bouts of high-intensity exercise is mixed, but it can benefit performance in repeated/intermittent bouts of high-intensity exercise.6-8 It should be noted that a carbohydrate-loaded state failed to increase endurance performance when carbohydrate was ingested during training.9 2-4 Hours Pre-Exercise Although it’s somewhat arbitrary, Howley and Burke cited the pre-exercise period (in the endurance context) as a 4-hour window prior to training that can be further divided into 2 parts:

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2-4 hours pre-exercise, and 30-60 minutes pre-exercise.10 In order to make the definition more literal, I would consider the immediate pre-workout phase as a period extending right up until the start of the exercise bout. Whether 60 minutes prior to training can be considered “immediate” is almost a matter of semantics, but I’ve personally viewed a 30 minute window pre-exercise as being more appropriate to the definition. In any case, various trials have examined anywhere from 140-330g carbohydrate taken 3-4 hours pre-exercise. This practice has been shown to enhance endurance performance, presumably by increasing muscle and liver glycogen levels. In a thorough review, Hargreaves and colleagues recommend ingesting 200-300g carbohydrate 3-4 hours pre-exercise in the event that during-training carbs will be limited or nonexistent.4 Take note that in well-trained endurance athletes, as much as a few hours’ delay might not make much difference in the effect of the pre-exercise meal. For example, Flynn et al found no significant difference in performance enhancement from a high-carbohydrate meal ingested either 4 or 8 hours pre-exercise.11 Finally, does the glycemic index (GI) of the pre-exercise meal matter? In non-competitive subjects, the research results are mixed, with no solid consensus in favor or against GI manipulation in the pre-exercise meal. However, with the exception of perhaps a single 1991 study,12 several trials since have shown that GI has no effect on endurance capacity in well-trained subjects.13-17 Within 60 Minutes Pre-exercise Before diving in, it’s important to acknowledge the different scenarios that end up dictating the protocol. Some folks train in the morning, so a meal 2-4 hours prior is not possible. Generally, the closer a meal is to the training bout, the easier it should be designed to digest. Individual tolerance comes highly into play here – some trainees are sensitive to the presence of food digesting during training, while others can train with a substantial bolus in the gut. For those who train in the morning almost immediately after waking, pre- and/or during-training liquid nutrition becomes important. Theoretically, a marked spike in blood glucose, followed by hypoglycemia during exercise might hinder performance, but the weight of the evidence doesn’t support this concern. Two early studies in the late 1970’s showed immediate pre-exercise carbohydrate’s potential to impair performance,18,19 while all of the subsequent research (totalling at least 9 studies) have shown either no effect, or a performance increase.4 Doses were typically 1g/kg of bodyweight given 30-60 minutes pre-exercise. Carbohydrate taken before and during high-volume resistance training has been seen to preserve muscle glycogen.20 This has led some researchers to suggest that this tactic can maintain or enhance resistance training performance. However, recent work by Baty et al saw no performance enhancement from approximately 1L of a protein (1.5%) and carbohydrate (6.2%) solution whose ingested pre-, during-, and post-exercise.21 Lack of ergogenesis aside, this treatment reduced myoglobin and creatine kinase levels, indicating an ability to suppress training-induced muscle damage.

Similarly, Tipton et al saw 6g of essential amino acids (EAA) plus 35g sucrose immediately before 45-50 minutes of resistance training cause 262% more amino acid uptake than the same treatment taken immediately afterward.22 Performance was not measured in this trial. In another trial led by Tipton, the protein-synthetic effect of 20g whey taken either immediately pre- or immediately post-exercise was compared.23 Although no significant differences in protein synthesis were seen, Tipton suggested that a protein-synthetic increase would be seen in the pre-exercise treatment if there were approximately double the number of subjects. It’s also likely that including carbohydrate with the protein would likely cause more readily detectable protein synthesis. Cribb et al compared the effect of a carbohydrate-protein-creatine supplement taken immediately pre- and post-resistance training with the same supplementation taken at two points in the day that were furthest away from the training bout.24 The dose was proportional to bodyweight (each of the 2 doses was roughly 32g whey, 34g glucose, and 5.6g creatine). The immediate pre-post group experienced greater gains in lean mass and strength. To top it off, they also lost a slight amount of body fat. DURING EXERCISE The objectives of during-exercise nutrition are the same as pre-exercise nutrition – to maintain hydration, blood glucose, and amino acids. Once again, the goals are to reduce the breakdown of glycogen and muscle protein, and promote muscle protein synthesis. During training, special attention should be paid to avoiding gastric distress and/or sensitivity to hypoglycemic dips (dictated by individual tolerance). The aspects we’ll examine are the amount, type, and form of the substrates during training to achieve these goals. With a substantial body of research in support, during-training carbohydrate has proven itself beneficial for endurance activity that approaches or exceeds 2 hours.25 Challenging the traditional idea that carbohydrate during training only benefits prolonged durations, an appreciable amount of research shows that it can enhance higher intensity training lasting roughly an hour.25-27 However, other trials have shown no effect, leaving this issue incompletely resolved.28-30 In Search of an Optimal Carbohydrate Dose So the question then becomes, how much carbohydrate during training is needed to optimize endurance performance? Before speculating over a definitive answer, it might help to first discuss carbohydrate oxidation rate. It was formerly believed that the maximal rate of carbohydrate oxidation by muscle during training was 1.2-1.3g/min when glucose and fructose were ingested at a rate of 1.8g/min.31 This is approximately 20-50% greater than the oxidation rate of glucose alone. Glucose and fructose have different transporters that can be utilized simultaneously for faster availability to muscle. More recently, an oxidation rate of 1.75g/min was seen as a result of ingesting a 1:1 proportion of glucose and fructose consumed at a rate of 2.4g/min.32 In addition, a combination of glucose and sucrose, or

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glucose and fructose, caused the least stomach upset during training compared with glucose alone or glucose with maltose.33,34 Proportion of fructose in each trial was 33% and 25%, respectively. A widespread assumption is that a higher rate of oxidation of ingested carbohydrate automatically equates to greater work capacity. Although this is often implied in the literature (and it’s also logical, since higher exogenous carbohydrate use can prevent glycogen use), it hasn’t been proven. Let me quote a review by Jeukendrup, one of the most prolific researchers in the area of sports applications of carbohydrate:25

“Although many studies (including our own) are based on this assumption, the evidence for this is lacking. To our knowledge no studies have demonstrated that ingesting larger amounts of CHO that will result in higher exogenous CHO oxidation rates will also enhance performance. Studies have shown effects of CHO feeding even with relatively low rates of intake (as low as 16 g/h), but generally no greater improvements have been observed with higher intake rates.” Despite the above explicit testimony that a larger amount of carbohydrate hasn’t been seen to increase performance, Jeukendrup goes on to say that the optimal amount is 60-70g/hr. This level of intake results in maximal exogenous oxidation rates without causing gastrointestinal problems. Exceeding the higher end of this amount increases the risk of gastrointestinal upset without any increase in carbohydrate use. At this point, I should reiterate that this recommendation is exclusive to endurance training. For strength/power athletes it’s safe to cut this recommendation approximately in half, and ingest 20-35g/hr. The wider range I’ve provided accounts for differences in body mass (little folks take the lower end, and large folks take the upper end, medium-sized trainees can shoot somewhere in the middle). Note that if the weight training bout is less than an hour, and a pre-exercise meal or shake was ingested within half an hour of training (or a large mixed meal within roughly 90 minutes before training), additional mid-training carbohydrate will have little benefit, if any at all. The same goes for protein, which we’ll look at next. Protein for Performance? A relatively new area of research is the addition of protein to sports drinks. Carbohydrate has a relatively consistent track record for increasing endurance performance, but protein for this purpose is still mixed and inconclusive. Some research has shown additional protein to increase endurance capacity (time to fatigue).35,36 One recent study saw a carbohydrate-protein gel increase endurance capacity better than a carbohydrate-only gel.37 However, 2 recent studies showed the failure of additional protein to improve time trial performance.38,39 Another study compared a carb-only solution with an isocaloric amount of a carb-protein-antioxidant supplement (which had 1.8% less carbohydrate than the carb-only treatment) and found no difference in time to fatigue.40 So what’s with all the discrepancies? The trials that found no effect of additional protein used amounts of carbohydrate in line with the amount required for maximal oxidation rate (60-

70g/hr). The trials that found an improvement with additional protein used substantially less carbohydrate (37-47g/hr). This indicates that additional protein is ergogenic only in the event that carbohydrate intake is insufficient. Another way to look at it is, above a certain threshold of carbohydrate intake during training (roughly 60g/hr), additional protein doesn’t enhance performance. Of special note is that the trials showing a lack of benefit from extra protein used a more applicable experimental model to real-life competition. Whereas the other trials measured time to exhaustion, these trials measured the time it took to complete a fixed amount of work. In many competition scenarios, and certainly all racing sports, those who complete the course in the least amount of time are the winners – as opposed to those who can keep going for the longest distance past the finish line. With that said, it’s tempting to write off protein during training as unnecessary, but the critical facts of the matter are two-fold. First off, protein doesn’t appear to hinder performance compared to carbohydrate alone – at least within the context of these trials, which set protein proportion at 20-25% of the solute. Secondly, protein consumed during exercise has consistently shown a greater suppressive effect than carbohydrate on training-induced muscle catabolism.35,36,40,41 Reduction of muscle damage can lead to quicker recovery and ultimately better training adaptations over time. For these reasons, it’s wise to make sure you’ve consumed protein prior to, and/or during exercise – regardless of whether or not its consumption during may improve performance. Note that only a small amount of essential amino acids (6g EAA) plus 675mL of a 6% carbohydrate solution (~40g CHO) taken during 60 minutes of resistance training effectively suppressed markers of muscle protein degradation. 41 Protein Dosage Speculations There’s at least a couple of ways to approach the question of how much protein might be optimal to ingest during training. A convenient way is to formulate protein recommendations in conjunction with the most commonly cited “optimal” during-training carbohydrate intake recommendation is 30-60g/hr,42 keeping in mind that others have cited 60-70g/hr.25 As we just reviewed in a series of trials,35,37-40 with the exception of one of them that set protein at 20% of the substrate mix,36 a 25% proportion of protein in the substrate mix has been seen to suppress muscle protein breakdown. Importantly, this amount did not hinder endurance performance. Therefore, an appropriate protein intake during training is approximately 8-15g/hr, which is 25% of the upper and lower ranges of carbohydrate intake recommendations most commonly seen in research. Another way to look at this question is by factoring in the protein absorption rates seen in research. Bilsborough and Mann recently compiled the results of trials examining the absorption rates of various proteins.43 Methodological limitations pervade the data, but it at least gives us a ballpark idea. Whey isolate was rated the second-fastest absorbed protein at 8-10g/hr, with an amino acid mixture mimicking pork tenderloin topping the field at 10g/hr (no lower range was listed). The latter treatment was via intravenous infusion, so its application is particularly limited.

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The investigators also cited other infusion data showing a peak absorption rate equivalent to 12g/hr for an 80kg individual. Proportionally, this turns out to be 0.15g/kg/hr. Using this figure, a 60 kg (132 lb) individual would have 9g/hr, whereas a 100 kg (220 lb) person would have 15g/hr. Interestingly enough, the two methods produce very similar numbers. An important thing to consider is that the protein absorption measurements were taken in the resting/basal state rather than the training or trained state. Depending on several factors, these physiological states can have significantly higher rates of protein turnover – and thus a higher demand for protein. Yet another factor to consider is that requirements based on bodyweight assume that we’re talking about an acceptable or desired maintenance bodyweight (also called ideal or target bodyweight). Current weight only applies if the person happens to be at their target bodyweight. Since high-quality intact proteins (such as whey) are roughly 50% EAA, a case can be built for using a smaller amount of isolated EAA, as much as 50% less than what you would use with intact proteins. However, if the isolated EAA strategy is chosen, be prepared to pay a minimum of twice as much for the amount of whole protein that would give you an equivalent amount of EAA. An additional consideration is that although inessential amino acids don’t directly trigger protein synthesis, they can serve as precursors of nitrogenous compounds with biologically important roles. The point is that they can’t be completely written off, and they may offer benefits beyond what’s been measured. To reiterate an easily overlooked point, if the training bout lasts less than 60 minutes, and a protein-containing pre-exercise meal or shake was ingested within half an hour of training (or a full-sized mixed meal within roughly 90 minutes before training), additional protein during training will likely have negligible benefit. Blood glucose and amino acid levels will already be in the midst of absorption as a result of the pre-exercise mixed meal. Remember that most trials use overnight-fasted subjects. Fluid & Electrolyte Balance Last but not least, we have fluid and electrolyte balance considerations. It’s fairly well-known that carbohydrate concentrations in the range of 4-8% of the fluid solution (40-80g per liter, or 10-20g per 8oz cup) optimizes the rate of fluid and carbohydrate delivery to tissues.42 As we saw in the previous subsection, protein and carbohydrate in a 1:3 ratio (25% protein, 75% carbohydrate) has not hindered performance compared to carbohydrate alone, as long as the overall solute concentration doesn’t exceed 4-8%. Whether research continues to show this neutral-to-beneficial effect of a small amount of protein in the mix remains to be seen. In theory, fluid intake should correspond with sweating rate, which will vary across training intensities, environmental temperatures, and individual tolerances. The American College of Sports Medicine’s former position stand recommended a ballpark range of 0.6-1.2 liters of fluid per hour.44 This was publicly criticized by Noakes as being excessive.45 Perhaps due in part to this criticism, ACSM’s latest position stand adopts

Noakes’ position that 0.4-0.8 liters per hour is a good starting point from which to assess any further need for fluid intake.46 Taken together, 0.5-1.0 liters per hour is a reasonable range for most athletes. As a final wrinkle, sodium chloride (the chemical equivalent of table salt) is released to a significant degree during prolonged training. For events lasting over an hour, the investigators recommend a sodium intake of 20-40mmol/liter (460-920mg/liter). For events in excess of 2 hours, a concentration of 30-50mmol/liter (690-1150mg/liter) doesn’t cause adverse effects, and protects endurance athletes from hyponatremia.47 In addition, salt stimulates thirst, increasing voluntary consumption of fluid and thus increasing hydration. As an example of products mirroring research, Gatorade’s original “Thirst Quencher” formula is 457mg/liter, and their new “Endurance” formula contains 832mg/liter. This formula is more appropriate for athletes engaging in ultra-endurance competition, while the original formula is suitable for bouts of training with less extreme durations. Commercial formulas contain one or more of the other electrolytes in sweat (potassium, calcium, and magnesium). However, there’s a lack of evidence of the necessity of supplementing mid-training intake with anything beyond sodium and chloride (easily accomplished by the salt in the sports drinks), since losses of the other electrolytes are miniscule and inconsequential.42,47-49 SUMMARY PRINCIPLES & PRACTICAL APPLICATIONS Hierarchy of Importance, Overview • At the top of the hierarchy of effects is total amount of the

macronutrients by the end of the day. Timing is secondary. • The vast majority of nutrient timing studies have been

done on overnight-fasted subjects, limiting the relevance of the results.

• Throughout the day, there’s a constant overlap of meal absorption, negating the need to spit hairs over the precision of meal placement.

• Most nutrient timing research is focused on carbohydrate for improving endurance, but data on protein and resistance training is mounting.

• The objectives of both pre- and during-exercise nutrition (especially in the endurance context) are to maintain sufficient levels of hydration, blood glucose, and amino acids.

Carbohydrate Loading Days Before Competition • The classic carbohydrate loading model consists of

approximately 3 days of a low carbohydrate intake (60-100g/day) combined with exhaustive exercise, followed by 3 days of very high carbohydrate intake (500-600g/day) and reducing training volume.

• This causes glycogen supercompensation, where stores are re-filled beyond their normal capacity.

• Linear carbohydrate elevations have been investigated in various trials (10-12.5g/kg, 1-7 days prior to testing), showing similar effects on glycogen supercompensation.

• Carbohydrate loading might not be necessary for improving endurance in competition lasting less than 90 minutes.

• Carbohydrate loading might not have additional performance benefits if ample carbohydrate (~60g/hr) is ingested during training.

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2-4 Hours Pre-Exercise • 140-330g carbohydrate taken 3-4 hours pre-exercise has

been shown to enhance endurance performance. • 200-300g carbohydrate is recommended 3-4 hours pre-

exercise in the event that during-training carbs are limited or nonexistent in endurance competition.

• In non-competitive subjects, the research results are mixed regarding glycemic index (GI) manipulation of the pre-exercise meal.

• The vast majority of research has shown that GI has no effect on endurance capacity in well-trained subjects.

• Even if you are a pre-competition endurance athlete whose event exceeds 90 minutes, it’s not necessary to ingest a huge pre-load (ie, 200-300g carbs) if you plan on doing the smart thing, which is fueling yourself during competition.

• Unless you’re a pre-competition endurance athlete, this meal typically ends up being whatever regular mixed meal (whole food meal containing protein, carbohydrate, fat) you have scheduled at the time.

• This incidental nature of this meal is the main reason there’s no cool little grey “application box”.

Within 60 Minutes Pre-exercise – Principles • Individual schedules sometimes must dictate this area of

nutrient timing – sometimes there’s no option for a meal 2-4 hours before training.

• Although a spike in blood glucose followed by hypoglycemia during exercise can occur as a result of having a high-carbohydrate meal within an hour of training, research on the whole does not warrant any performance concerns.

• Low-to-moderate volume resistance training bouts may not depleting enough to derive performance benefits from pre-exercise carbohydrate.

• As little as 6g EAA + 35g sucrose immediately pre-exercise has been observed to promote protein synthesis more effectively than the same treatment immediately after exercise.

• As for having isolated amino acids (EAA and BCAA are the most popular), let me reiterate that whey contains about 50% EAA, half of which is BCAA. To top things off, whey contains compounds that exert pro-immune, antioxidant, and antibacterial effects. These compounds are absent in isolated amino acid supplements. A detailed review of the therapeutic potential of whey can be found here.

• Positioning macronutrients immediately surrounding training (as opposed to deferring them from either side) has resulted in superior strength and body composition changes.

• In private practice, clients have the choice of having one of two ‘immediate’ pre-exercise meals (I wish the following could be more succinct, but here it goes):

WITHIN 60 MINUTES PRE-EXERCISE – APPLICATION Consume either one of the following choices:

a) A solid meal consisting of protein and carbohydrate set at (0.25g/lb) target bodyweight for each of the two macronutrients, ingested 60-120 minutes pre-exercise. For example, a 160 lb person would have 40g carbs plus 40g protein. Tolerance for pre-exercise fat is an individual matter best left to personal trial. In my observations with clientele, any amount of fat within moderation here generally doesn’t hinder exercise performance. You’d have to really go out of your way – not to mention overshoot your target for total fat intake for the day – in order to cause any real performance detriments at this point. Don’t obsess over specific subtypes of food (i.e., chicken versus steak, rice versus pasta, apples versus oranges, etc); just stick to your personal preferences.

b) A shake at any point within 30 minutes pre-

exercise, or an easily digested meal within anypoint 60 min pre-ex. Same dose as choice (a).stick to your personal food preferences. Individuals who train immediately after waking might need to minimize digestion and mix up a shake consisting of whey protein powder and a carb source. Sucrose (table sugar) will do just fine, although some may want to nitpick and combine dextrose or maltodextrin with sucrose in an even proportion (this will set fructose at 25% of the mix).

Technically, if you finish a whey/carb shake near the start of training, it’s fine for it to be roughly an even mix of carbohydrate and protein in the robust amounts suggested above. However, this is not an optimal mid-training mix for endurance athletes; it has too high a proportion of protein. Those who are headed straight for a prolonged training bout (meeting or exceeding 2 hours of endurance exercise) immediately after waking will benefit by starting on their during-exercise fuel, which has a different composition than the above-discussed pre-exercise meal format, to be outlined next.

During Exercise – Principles • The objectives of during-exercise nutrition are the same as

pre-exercise nutrition – to maintain hydration, blood glucose, and amino acids.

• It’s generally agreed that carbohydrate during training can benefit endurance exercise approaching or exceeding 2 hours.

• Although an appreciable amount of research shows that during-training carbohydrate can enhance higher intensity

training lasting roughly an hour, other trials have shown no effect, leaving this issue incompletely resolved.

• Along with a higher oxidation rate (potentially a good thing for sparing glycogen), less gastrointestinal upset is reported when fructose is included in a mix of carbohydrate – as opposed to glucose or fructose alone.

• Adding protein to carbohydrate during training (approximately 1 part protein, 3-4 parts carbohydrate) has shown mixed results in the literature. It appears to offer some benefit when carbohydrate isn’t ingested in ample amounts (~60g/hr).

• The trials showing a lack of benefit from extra protein used a more applicable experimental model to real-life competition.

• Protein (as well as protein plus carbohydrate) consumed during exercise has consistently shown a greater suppressive effect than carbohydrate alone on training-induced muscle catabolism.

• Sodium chloride (the chemical equivalent of table salt) is lost from the body to a significant degree during training that exceeds 2 hours.

• It bears repeating that during-training carbohydrate, protein, and electrolyte concerns are practically nil for most trainees whose exercise bouts do not meet or exceed 60 minutes – as long as proper pre-exercise nutrition is in place.

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REFERENCES 1. Bergstrom et al. Diet, muscle glycogen and physical

performance. Acta Physiol Scand. 1967 Oct-Nov;71(2):140-50. [Medline]

2. Keith RE, et al. Alterations in dietary carbohydrate, protein, and fat intake and mood state in trained female cyclists. Med Sci Sports Exerc. 1991 Feb;23(2):212-6. [Medline]

3. Prusakszyc, et al. No effects of glycogen depleting exercise and altered diet composition on mood states. Med Sci Sports Exerc. 1992 Jun;24(6):708-13. [Medline]

4. Hargreaves M, et al. Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance. J Sports Sci. 2004 Jan;22(1):31-8. [Medline]

5. Sherman WM, et al. Effect of exercise-diet manipulation on muscle glycogen and its subsequent utilization during performance. Int J Sports Med. 1981 May;2(2):114-8. [Medline]

6. Balsom PD, et al. High-intensity exercise and muscle glycogen availability in humans. Acta Physiol Scand. 1999 Apr;165(4):337-45. [Medline]

7. Bangsbo J, et al. Effect of diet on performance during recovery from intermittent sprint exercise. Int J Sports Med. 1992 Feb;13(2):152-7. [Medline]

8. Nicholas CW, et al. Carbohydrate intake and recovery of intermittent running capacity. Int J Sport Nutr. 1997 Dec;7(4):251-60. [Medline]

9. Burke LM, et al. Carbohydrate loading failed to improve 100-km cycling performance in a placebo-controlled trial. J Appl Physiol. 2000 Apr;88(4):1284-90. [Medline]

DURING EXERCISE – APPLICATION • Carbohydrate intake recommendations for endurance

training are split between a conservative side (30-60g/hr) and liberal side (60-70g/hr). The lower range will suit less intense endurance work.

• Either sucrose or a 1:1 ratio of glucose and sucrose (which would bring the fructose proportion down to 25%) will work equally well for endurance athletes. Most commercial sports drinks fit this profile.

• Protein intake of 0.15g/kg/hr may prevent training-induced muscle damage. This translates to roughly 9-15g/hr. This can be accomplished by adding nearly a scoop of protein powder (~15g protein) to every liter (32 oz) of commercial sports drink containing 60g carbohydrate.

• 0.5-1.0 liters per hour is a reasonable ballpark range of fluid intake for most athletes. Trial and error can determine needs that fall outside of this range.

• Regardless of total amount of fluid ingested, it should be 4-8% carbohydrate – about 40-80g per liter, or 10-20g per 8oz cup. About 150-350mL (6-12oz) every 15-20 minutes should be consumed.

• For events longer than 60 min, a sodium intake of 20-40mmol/liter (460-920mg/liter) is recommended.

• For events in excess of 2 hours, a concentration of 30-50mmol/liter (690-1150mg/liter) is recommended.

• If you’re not inclined to home-brewing the proper carbohydrate and electrolyte mix, commercial sports beverages such as Gatorade have already done it.

10. Howley JA, Burke LM. Effect of meal frequency and timing on physical performance. Br J Nutr. 1997 Apr;77 Suppl 1:S91-103. [Medline]

11. Effects of 4- and 8-h preexercise feedings on substrate use and performance. J Appl Physiol. 1989 Nov;67(5):2066-71. [Medline]

12. Thomas DE, et al. Carbohydrate feeding before exercise: effect of glycemic index. Int J Sports Med. 1991 Apr;12(2):180-6. [Medline]

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19. Costill DL, et al. Effects of elevated plasma FFA and insulin on muscle glycogen usage during exercise. J Appl Physiol. 1977 Oct;43(4):695-9. [Medline]

20. Haff GG, et al. Carbohydrate supplementation and resistance training. J Strength Cond Res. 2003 Feb;17(1):187-96. [Medline]

21. Baty JJ, et al. The effect of a carbohydrate and protein supplement on resistance exercise performance, hormonal response, and muscle damage. J Strength Cond Res. 2007 May;21(2):321-9. [Medline]

22. Tipton KD, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206. [Medline]

23. Tipton KD, et al. Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab. 2007 Jan;292(1):E71-6. [Medline]

24. Cribb PJ, Hayes A. Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy. Med Sci Sports Exerc. 2006 Nov;38(11):1918-25. [Medline]

25. Jeukendrup AE. Carbohydrate during exercise and performance. Nutrition. 2004 Jul-Aug;20(7-8):669-77. [Medline]

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29. Palmer GS, et al. Carbohydrate ingestion immediately before exercise does not improve 20 km time trial performance in well trained cyclists. Int J Sports Med. 1998 Aug;19(6):415-8. [Medline]

30. Powers SK, et al. Fluid replacement drinks during high intensity exercise: effects on minimizing exercise-induced disturbances in homeostasis. Eur J Appl Physiol Occup Physiol. 1990;60(1):54-60. [Medline]

31. Jentjens RL, et al. Oxidation of combined ingestion of glucose and fructose during exercise. J Appl Physiol 2004; 96: 1277-84. [Medline]

32. Jentjens RL, Jeukendrup AE. High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. Br J Nutr. 2005 Apr;93(4):485-92. [Medline]

33. Jentjens RL, et al. Oxidation of exogenous glucose, sucrose, and maltose during prolonged cycling exercise. J Appl Physiol. 2004 Apr;96(4):1285-91. [Medline]

34. Jentjens RL, et al. Oxidation of combined ingestion of glucose and fructose during exercise. J Appl Physiol. 2004 Apr;96(4):1277-84. [Medline]

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37. Saunders MJ, et al. Consumption of an oral carbohydrate-protein gel improves cycling endurance and prevents postexercise muscle damage. [Medline]

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43. Bilsborough S, Mann N. A review of issues of dietary protein intake in humans. Int J Sport Nutr Exerc Metab. 2006 Apr;16(2):129-52. [Medline]

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Carbohydrate-Protein Drinks Do Not Enhance Recovery From Exercise-Induced Muscle Injury Green MS, et al. Int J Sport Nutr Exerc Metab. 2008 Feb;18(1):608-23. [IJSNEM] PURPOSE: To examine the effects of carbohydrate (CHO), carbohydrate-protein (CHO+PRO), or placebo (PLA) beverages on recovery from novel eccentric exercise. METHODS: Female subjects (age = 18-35 yrs) performed 30 min of downhill treadmill running (–12% grade, 8.0 mph), then consumed a CHO, CHO+PRO, or PLA beverage immediately, 30, and 60 min post-exercise. CHO and CHO+PRO groups consumed 1.2g/kg/hr CHO, with the CHO+PRO group consuming an additional 0.3g/kg/hr PRO. The PLA group received a noncaloric beverage. Maximal isometric quadriceps strength (QUAD), lower extremity muscle soreness (SOR), and serum creatine kinase (CK) were assessed pre-injury (PRE) and immediately and 1, 2, and 3 days post-injury. RESULTS: There was no effect of treatment on recovery of QUAD, SOR, or CK. In all groups, QUAD was reduced compared with PRE by 20.6%, 17.2%, and 11.3% immediately, 1, and 2 days post-injury, respectively. SOR peaked at 2 days post-injury, and serum CK peaked 1 day post-injury. CONCLUSIONS: consuming a CHO+PRO or CHO beverage immediately after novel eccentric exercise failed to enhance recovery of exercise-induced muscle injury differently than what was observed with a PLA drink. SPONSORSHIP: Not listed. Study Strengths The subjects in each treatment group were evenly matched in average height, weight, and bodyfat percent. The testing was done under non-fasted conditions, which more closely mirrors real life – versus previous research which tested subjects in a glycogen-depleted state minus a pre-exercise meal. Too bad the pre-exercise meal wasn’t controlled, but I’ll get to that. Another methodological strength was the use of dual-energy X-ray absorptiometry (DEXA) to measure body composition. Study Limitations Sample size (6 subjects per treatment group) was small. A low-to-moderate level (1-5 hours per week) of habitual aerobic exercise was one of the participant criteria, potentially limiting the results to the novice or casual trainee. This population is likely much more susceptible to muscle damage than highly trained athletes. But those are minor/common limitations compared to this study’s complete disregard for dietary control outside of the testing period. Subjects arrived at the lab 2-3 hours after finishing a meal which was not controlled, let alone standardized. As a matter of fact, diet was not controlled nor accounted for throughout the length of the study. The lack of dietary control is difficult to reconcile, especially since the effects under investigation were contingent upon the interaction between diet and training variables. Finally, this was an acute-effect trial, tracking the outcomes over a period of days rather than weeks.

Comment/Application This is perhaps the second study to ever investigate the effect of a protein-carbohydrate beverage taken solely after injury-inducing exercise. The only other trial was by Wojcik et al, who compared a protein-carbohydrate milk-based beverage with a carb-only beverage. Fasted subjects were taken to glycogen depletion using eccentric quadriceps contractions. There were no significant differences in muscle protein breakdown as indicated by 3-methylhistidine release. Creatine kinase levels (an indicator of muscle catabolism) were lower in the protein-carb group, but not to a degree of statistical significance. Although the general lack of effect was shared by both studies, the present trial was perhaps more broadly applicable because the exercise protocol was less extreme, and the subjects weren’t fasted. Just by reading the title and the abstract of the study, it’s possible that some might jump to the conclusion that post-exercise protein-carbohydrate solutions are useless. However, it’s critical to remember that post-exercise “recovery” drinks are designed to complement (and potentially synergize with) the other meals. In the case of inflicting eccentric contraction-induced muscle damage, inadequate pre- and/or during-training nutrition followed by a recovery drink is sort of like jumping into a pool with Jaws, then putting a band-aid over the shark bites. Preventive nutrition would have served as the shark cage upon entering the water. Granted, shark bites are a little more severe than elevated creatine kinase levels, but you get the point. Speaking of more appropriate nutrient timing protocols, other investigations have examined the effects of protein-carbohydrate solutions given pre- and/or during exercise, with some of these studies lasting several weeks. The results unanimously support the use of a protein-carbohydrate mix for suppressing markers of muscle damage. For example, a relatively recent trial by Saunders et al compared a carbohydrate-only beverage with a carb-matched beverage containing additional protein (an extra 20%) drank during and after exercise. The latter treatment enabled subjects to cycle 29% longer to fatigue at 75% VO2max and 40% longer at 85% VO2max compared to the carb-only group. Despite the substantially greater workload done by the carb-protein group, it had 6x lower creatine kinase output than the carb-only group, indicating significantly less muscle damage. Here’s a quote from the discussion section of the present trial: “Although these studies did not seek to specifically cause exercise-induced muscle injury, the activities performed by the participants are likely candidates for its induction. Thus, it is possible that chronic use of carbohydrate-protein beverages will enhance the recovery from repeated bouts of exercise-induced muscle injury.” The moral of the story is that if you’re involved with activity that contains a high volume of repeated bouts of eccentric contractions (such as downhill running), special attention must be paid to nailing your pre- and if necessary, during-exercise nutrition, not just post-exercise. Here’s a link back to the opening article if you need a refresher on how to accomplish this.

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Effect of dietary protein content during recovery from high-intensity cycling on subsequent performance and markers of stress, inflammation, and muscle damage in well-trained men. Rowlands DS, et al. Appl Physiol Nutr Metab. 2008 Feb;33(1): 39–51 [APNM] PURPOSE: To determine the effect of post-exercise dietary protein content imposed over a high-carbohydrate background on subsequent performance. METHODS: Using a crossover design, 12 cyclists completed 3 high-intensity rides over 4 days. Day 1 comprised 2.5 h intervals, followed by repeat-sprint performance tests on days 2 (15 h post) and 4 (60 h post), interspersed with a rest day. During 4 h recovery on days 1 and 2, cyclists ingested either 1.4g/kg/hr carbohydrate, 0.7g/kg/hr protein and 0.26g/kg/hr fat (protein-enriched) or 2.1g/kg/hr carbohydrate, 0.1g/kg/hr protein, and equal fat (control). At other times, cyclists ingested a standardized high-carbohydrate diet. Anabolism was assessed via nitrogen balance, stress and inflammation via cortisol and cytokines, skeletal-muscle membrane disruption via creatine kinase (CK), and oxidative stress via malonyl dealdehyde (MDA). RESULTS: Sprint mean power was not different on day 2, but on day 4 it was 4.1% higher in the protein-enriched condition. CK was reduced by 26% but other effects were inconclusive. Overnight nitrogen balance was positive in the protein-enriched condition on day 1, but negative in the control. CONCLUSION: A nutritive effect of post-exercise protein content was not detectable short-term (15 hrs), but a delayed performance benefit (60 hrs) was observed. SPONSORSHIP: The researchers of this study funded it themselves. Study Strengths Trained endurance endurance cyclists were used, which eliminates the possibility of results coming from the “newbie effect”. The latter is generally responsible for suppressing potential differences between groups due to an indiscriminately high level of responsiveness that novices have to any given protocol. Subjects recorded their training and diet daily in lab-provided journals. Dietary intake was standardized throughout the trial to contain 8-10g of carbohydrate per kg of fat-free mass, and reality-based feeding patterns were mimicked. On day 1, subjects underwent a glycogen depletion protocol 4 hours after a 1pm meal. On day 2 and 4, where the subjects arrived at the lab first thing in the morning, a normal training day was simulated by consuming a small standardized high-carbohydrate meal before the repeated sprint tests. Speaking of which, instead of using a fixed load time-to-exhaustion model of testing, the measurement of a maximal effort over repeated sprints more accurately reflected the intermittent high-intensity bouts of many types of sport, including endurance cycling competition. Study imitations I use the skinfold method in my private practice, so it feels a little strange to be criticizing studies that use the same method. However, I make it perfectly clear to my clients that they’re used because 1) I can choose which specific sites to assess; 2) They’re

reliable enough at measuring change in skinfold thickness, regardless of how closely the caliper-determined bodyfat percent estimate relates to what the client’s actual bodyfat percent might be. I’m very clear with my clients that the only way to determine bodyfat percent with the highest degree of accuracy is dissection – which has obvious side effects. This brings me to my point that I’d rather see either hydrodensitiometry or DEXA used in research where much of the outcomes hinge upon as accurate an assessment of body composition as possible. In the case of the present study, many of the calculations and feeding dosages were based on the subjects’ fat-free mass, which ultimately falls back on the accuracy (or lack of accuracy) of the body comp assessment method. Nitrogen balance as a tool for measuring anabolism has its fair share of limitations. This study measured urinary nitrogen losses, but only estimated other nitrogen losses through sweat, feces, and other means. Unfortunately, there will always be a built-in degree of possibility for under- and over-estimation of nitrogen losses due to factors such as denitrification by colonic bacteria, and further urea losses from skin and expired ammonia. For these reasons, it would have helped to use another method in tandem for cross-checking purposes, such as a metabolic tracer to determine muscle protein balance. Comment/Application The most important finding of this study was that it took roughly 2 and a half days for any performance effect to become evident. The fact that a performance benefit happened at all in the protein-enriched group was notable, since the control group consumed 1.2g/kg/day (50% above the RDI). This is within the range of protein intake recommended for athletes, which is 1.2-1.7g/kg/day (see the review by Tipton and Wolfe). And still, it wasn’t enough to prevent the control group from falling into negative nitrogen balance. The protein-enriched group consumed an average of 1.9g/kg/day, and this not only preserved nitrogen balance, but it imparted an eventual performance enhancement, as well as a reduction of creatine kinase (a marker of muscle breakdown) on day 4. According to the authors’ calculations, a 50mg/kg net loss of fat free mass occurred in the control group on day 1. This translates to 54g of protein lost over the 4 day trial, as opposed to a gain of 95g in the protein-enriched group. An extra 13.5g protein per day, which is the equivalent of 2 ounces of meat, or about 2/3 the typical sized scoop of protein powder would have been sufficient for preserving protein balance. The results may all boil down to the “protein enriched” treatment (contributing to a total of 1.9g/kg/day) merely enabling a protein intake within range of what athletes habitually ingest without any special effort. Illustrating my point, the authors point to a study of the macronutrient intake of top-level cyclists on the 3-week tour who consumed protein at about 3g/kg, which was 14.5% of total intake of 5600 kcal. In future research it would be interesting to see if pre and/or post-exercise protein enrichment leading to a total intake substantially above 1.9g/kg would cause any further increase in performance or suppressive effects on markers of muscle breakdown.

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Effects of a supplement designed to increase ATP levels on muscle strength, power output, and endurance. Herda TJ, et al. J Int Soc Sports Nutr. 2008 Jan 29;5(3) [JISSN] PURPOSE: To examined the acute effects of a nutritional supplement intended to improve adenosine triphosphate (ATP) concentrations on vertical jump height, isometric strength of the leg extensors, leg extension endurance, and forearm flexion endurance. METHODS: Twenty-four healthy men (mean age = 23yrs) completed a familiarization trial plus 2 randomly-ordered experimental trials separated by a 7-day washout period. Participants the supplemental treatment (TR; 625 mg of adenylpyrophosphoric acid and calcium pyruvate, 350.8 mg of cordyceps sinensis extract and yohimbine hydrochloride) or placebo (PL; 980 mg of microcrystalline cellulose) 1 hour prior to the following tests: countermovement vertical jump (CVJ), forearm flexion repetitions to exhaustion, isometric maximal voluntary contractions (MVCs) of the leg extensors, and a 50-repetition maximal concentric isokinetic leg extension endurance test. RESULTS: There were no differences between the TR and PL trials for CVJ height, isometric MVC peak torque, maximal concentric isokinetic peak torque, percent decline during the leg extension endurance tests, or repetitions to exhaustion during the forearm flexion endurance tests. CONCLUSION: No improvements occurred as a result of ingesting this supplement. Future studies should examine whether chronic supplementation or a loading period is necessary to observe any ergogenic effects. SPONSORSHIP: Not listed. Study Strengths At an average age of 23, it seems the appropriate age demographic was tested (young, impressionable). I’ve actually come across peer-reviewed supplement research that was single-blind, so I’ve come to appreciate, or at least have an eye out for double-blinding in this area of research. Another study strength was its crossover, meaning that experimental and control groups swapped spots after a 7-day “washout” period, and all the subjects all got to be tested with the supplement. 7 days was a sufficient period for eliminating any residual effects of the supplement or the performance tests. Study Limitations The authors noted that because the supplement didn’t improve performance, it’s possible that it simply did not increase ATP availability to the body. This could have been a result of the compound getting inactivated by the digestion process. But since no blood tests or biopsies were done to assess ATP levels, there’s no way to know for sure whether it was an issue of availability, or an issue of ATP’s ineffectiveness within the context of the supplement. Comment/Application Google searches bring up the darndest things. The Just JumpTM mat was used to measure vertical jumping ability in this trial.

The odd thing about the apparatus is that you have to land with your legs relatively straight so as not to alter the measurement of how much flight time you achieved. Here’s a video of the apparatus in use. Notice the urban slang congratulation banter after the jump, it kind of makes the clip. Since the company distributing the supplement was listed in the study (5-TETRA by Epic Nutrition), Google came in handy again. Here are some of the claims on the front page of the company’s website, all of which the present study invalidated:

5-TETRA is the ideal pre-workout supplement for increased Strength and Endurance. • Immediate Performance Increase • Increase ATP Levels • Accelerate Recovery

I’m not sure what sort of politics – if any – may have been involved with the proceedings of the study, but the ineffectiveness of 5-TETRA was exposed handily. I mention politics because at least one of the authors of this trial (Jeffrey Stout), as well as Jose Antonio, the co-founder of the journal in which this trial was published, are both heavily involved in the development and marketing of various supplements. Either Epic Nutrition was not on their affiliate list, or the authors were simply were doing their job as scientists for the interest and protection of the consuming public. I’ll stay optimistic towards the latter. I own the book Sports Supplements by Antonio & Stout, and it’s a very thorough, well-done, although currently out-dated text. 5-TETRA is a mix of ingredients with sketchy track records, so its lack of ergogenic effect was not too surprising. A 14-day study by Jordan et al examined the effect of an oral ATP supplement on anaerobic power and strength. The lower dose of ATP (150mg) was ineffective for all parameters tested, while the higher dose (225mg) failed at significantly improving all parameters except for modestly increasing total lifting volume. As listed in the present trial, 5-TETRA contains 625mg of a mix of adenylpyrophosphoric acid and calcium pyruvate. Since no proportions were listed, anything is possible here. Adding to the history of calcium pyruvate supplementation’s marginal effectiveness, a relatively recent trial showed its failure to significantly alter body composition or improve exercise capacity. Furthermore, the supplement actually inhibited the HDL-raising effect of exercise. Lastly, the product has 350.8 mg of cordyceps sinensis extract and yohimbine hydrochloride, and again, no specific amount of each is listed. Cordyceps sinensis is a larva-bound fungus used in traditional Chinese medicine for a number of purposes, including the increase of physical stamina. Unfortunately for those attempting to market it as an endurance agent, it has failed in the peer-reviewed literature for this purpose, both in combination with other compounds, and by itself. Yohimbine has been touted for its ability to increase lipolysis and thus reduce bodyfat, but research has been hit and miss. The latest yohimbine trial showed some fat loss effectiveness in elite soccer players, but no performance benefit was seen. Yohimbine supplementation has some promise for fat loss, especially if you train in a fasted state - which isn’t conducive to increasing strength or endurance.

One-year ad libitum consumption of diacylglycerol oil as part of a regular diet results in modest weight loss in comparison with consumption of a triacylglycerol control oil in overweight Japanese subjects. J Am Diet Assoc. 2008 Jan;108(1):57-66. [Medline]

PURPOSE: To investigate the effect of 1-year ad libitum consumption of diacylglycerol oil on body weight and serum triglyceride. METHODS: In a 1-year double-blind, placebo-controlled parallel trial with clinic visits at month 0, 3, 6, 9, and 12, a total of 312 Japanese men (174) and women (138) aged 22-73 years, with body mass index (BMI) >/=25 and/or fasting serum triglyceride level >/=150 mg/dL (1.70 mmol/L) were randomly assigned to the diacylglycerol (DAG) or triacylglycerol (TAG) group. Participants substituted their usual cooking oil with the test oils. RESULTS: Body weight decreased significantly in the DAG group. Changes in body weight and body mass index during the study period differed between the two groups by 0.87 kg and 0.32 kg, respectively. Participants with higher initial BMI or greater percentage of total fat intake as diacylglycerol had greater reductions in body weight. Serum triglyceride levels decreased significantly in individuals with hypertriglyceridemia, but did not differ between groups. CONCLUSION: Modest body weight reduction was observed after 1-year ad libitum consumption of DAG oil as part of a regular diet in comparison to that of triacylglycerol oil. SPONSORSHIP: Kao Corporation, Tokyo, Japan.

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Study Strengths Perhaps the most obvious strengths here are the 12-month study duration and the large number of subjects (312). But, these elements also raise the sensors up for what commercial entity might be able to fund a trial of this length – more on that in a minute. At each visit, a registered dietitian reviewed diet records and verified their accuracy by interviewing the participants. Diet records were analyzed by food and nutrition professionals who were specifically trained in nutritional assessment using computer software. Subjects were encouraged to maintain their usual eating habits and physical activity. Study Limitations Research, like life, is full of irony. This study undoubtedly must have cost a small fortune, yet a very crude method was employed for body composition analysis – 2-site caliper readings. Hydrodensitiometry or dual-energy X-ray absorptiometry (DEXA) would have been much more appropriate. Judging fro the accompanying news article excerpt, the study sponsor certainly could have afforded such methods. Although physical activity was accounted for via questionnaire, it’s always ideal if subjects are administered a structured exercise program that involves resistance training. Admittedly, the proper execution of a formal training protocol would be cost-prohibitive with a trial this size and length. Although diet records were reported to a dietitian, only 3 arbitrary consecutive days (not weekends excluded) were recorded and submitted with each quarterly visit. Another critical limitation was the burden of oil dose accuracy being placed on the participants, who self-

reported their intake. No clinical biomarkers were used to quantify changes in blood or tissue levels of the test oils. Comment/Application DAG-rich oil is the result of an esterification process where soy and canola oil are subjected to an enzyme which acts upon the 1 and 3 positions of the glycerol molecule. The result is a product sold under the trade name Enova™. The thing that irks me about this trial is that despite its dichotomous results, its conclusion will be used as an advertising headline. Here’s a bit of background on the study’s funding source straight from Kao Corporation’s website, in a news article entitled “ADM Forms Joint Venture to Produce Fat-Fighting Oil”:

Kao is focusing on the expansion of its business globally, as well as its health-related products. "This alliance with ADM will facilitate the rapid global expansion of DAG oil," said Takuya Goto, President of Kao. Kao has more than 22,000 employees worldwide and net sales of approximately $7.9 billion. ADM has over 23,000 employees, 368 processing plants, and net sales for the fiscal year ending June 30, 2000 of $18.6 billion.

Is any real excitement warranted? Is this a break-through “fat-fighting oil” as it’s been marketed? It should go without saying that a high degree of caution must always be used when interpreting study results. While it’s true that a statistically significant degree of weight and fat loss was seen in the diacylglycerol group compared to the triacylglycerol group, the actual differences were very small – in fact they were downright negligible. The participant subgroup whose BMI was at or greater than 30 lost an average of 1.5 kg (3.3 lbs) more than the triacylglycerol group – over the course of a year. That’s a little over a quarter-pound per month, good grief. Those with a BMI of 25-30 lost 0.5 kg (2.2) more than the triacylglycerol group during this 12 month trial. This gives a whole new meaning to the word “modest” in the title of this study. Subjects in the highest BMI bracket actually experienced an increase in both waist circumference (0.9cm) and triceps skinfold thickness (1.9mm). This finding was conveniently ignored in the discussion section of this study. In addition to being marketed as a weight loss aid, DAG is also hyped as an agent for significantly improving blood triacylglycerol levels. In the present trial, this was not the case. Applying the present study to the big picture, it’s clear that substituting one type of cooking oil in your diet for another ‘special’ engineered oil isn’t likely to fulfill any fat loss promises. But in the end, the main problem is that consumers as well as unknowing professionals will be taken by the headlines of the peer-reviewed research, and accept it as valid without question. This is a perfect example of how critical analysis can’t automatically stop at the lay literature. Scientific literature often hides under the veil of legitimacy, skates by unchecked, and gets leveraged for the benefit of the corporations funding the studies. Imagine using research showing virtually undetectable weight loss to market premium-priced cooking oil... Now, that’s slick.

Alan Aragon’s Research Review, February, 2008                                  [Back to Contents]                  Page 13 

Metabolic and performance effects of raisins versus sports gel as pre-exercise feedings in cyclists. Kern M, et al. J Strength Cond Res. 2007 Nov 1;21(4):1204-1207. [Medline] PURPOSE: To examine potential differences in metabolism and cycling performance after consumption of raisins vs. a high glycemic commercial sports gel. METHODS: Eight endurance-trained male and female (even split) cyclists, mean age = 30 yrs, completed 2 trials in random order. Subjects consumed carbohydrate at 1g/kg bodyweight from either raisins or sports gel (Clif Shot) 45 minutes prior to cycling at 70% VO2max. After 45 minutes of submaximal exercise, subjects completed a 15-minute performance trial. Blood was collected prior to starting, and at the 45th minute of exercise, to measure glucose, insulin, lactate, free fatty acids (FFAs), triglycerides, and beta-hydroxybutyrate (BHB). RESULTS: Performance was not different between the raisin and gel trials. Pre-exercise, glucose and other substrates did not differ between trials; however, insulin was 44.2% higher for the gel vs. raisin treatment. After 45 minutes of exercise, insulin decreased to similar levels in both trials. FFAs increased significantly during the raisin trial. CONCLUSION: Inconsequential metabolic differences and no difference in performance were detected. Raisins appear to be a cost-effective pre-exercise carbohydrate in comparison to sports gel for short-term exercise bouts. SPONSORSHIP: A grant from the California Raisin Marketing Board. Study Strengths There is an inherent practicality in the core concept of this study. If all it takes is a measly bunch of raisins for an ergogenic effect, and it costs about 40% less per gram of carbohydrate compared to sports gel, then it’s a win-win. But can this be possible? Can Mother Nature keep up with the tireless work of the sports supplement engineers? If you took the time to read the abstract, apparently, she can – at least within the context of the present protocol. Aside from practical allure, a decent host of metabolic parameters were assessed in addition to the most important one – exercise performance. Consistent with an emerging trend in performance testing, instead of using a constant-load, time-to-exhaustion model of testing, the measurement of a maximal effort over fixed amount of time more closely reflects the nature of sports competition. Using in-season trained cyclists – including triathletes and duathletes gave this trial relevance to the population that might care most about the small details that might make a difference under highly competitive conditions. Study Limitations In my opinion, the investigators wasted their energy by clamoring over the glycemic index (GI) differences of the two carbohydrate sources. Better resources could have been put to use by carrying the study through a longer duration instead of leaving it at a single performance bout. Had the trial been prolonged for several weeks, not only performance, but changes

in body composition, glucose, and lipid metabolism could be assessed as well. Comment/Application To reiterate a point I made in the opening article, rebound hypoglycaemia during training is an unsubstantiated concern regarding carbohydrate intake within 60 minutes prior to training. With the exception of 2 studies done in the 1970’s, at least 9 studies since then have shown either no effect, or a performance increase as a result of ingesting a wide range of carbohydrate types at 1g/kg of bodyweight ingested 30-60 minutes pre-exercise. Trained endurance athletes for the most part are unaffected by GI manipulations in general, regardless of the timing of a meal prior to exercise. Any potential effect that GI might have diminishes even further if the training bout is relatively short (equal to or less than 60 minutes), such as the protocol used in this study. For those reasons, all of the GI business was largely irrelevant to the context of this trial. An unexpected occurrence was a lack of difference between pre- and post-exercise serum glucose levels. Since lower-GI foods tend to evoke a lower insulin response, a more sustained level of glucose was expected during the outset of exercise compared to the gel treatment, which was expected to cause a more dramatic spike and dip. This was not the case. Lower blood lactate levels post-exercise were also expected of the raisin trial, since this would concur with less carbohydrate oxidation and greater fat oxidation. This didn’t happen either, perhaps the exercise duration was too short to give those phenomena a chance to become detectable. Since pre-exercise insulin levels were significantly higher in the gel group than the raisin group, the suppression of lipolysis and decreased FFA levels were expected. Nevertheless, a greater reliance on FFAs “sparing” the oxidation of carbohydrate could potentially increase performance, but again, this was not seen in this short-term bout. However, remember that trained subjects have been observed to be impervious to GI manipulations, even in prolonged training bouts. On to the nitty-gritty. Performance was not significantly different between the raisins or Clif Shot gel. The authors speculate that if a lower GI really was a potential performance factor, this possibility was diminished by the subjects carrying sufficient levels of glycogen prior to testing. However, they do diligently note that GI still might not have made any difference regardless, as seen in a trial by Febbraio et al. So, granted that the California Raisin Marketing Board doesn’t soon get one-upped by the many sports gel companies, a green light can be given to stick with the cheapest, most convenient carbohydrate source that you’re gastrically comfortable with – and of course suits your taste buds. As long as the training bout is less than 2 hours, it isn’t likely that you’d need any of the extra ingredients typical of gels (sodium & potassium). As done in this and other studies, a 1g/kg dose of carbohydrate was ingested 45 minutes pre-exercise. This is equivalent to about 2-3 small boxes of raisins, or 3-4 packets of sports gel. Both are equally effective, the raisins cost 40% less, but unlike most cutting-edge ergogenic aids, you actually have to chew them.

Alan Aragon’s Research Review, February, 2008                                  [Back to Contents]                  Page 14 

Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial. Das SK, et al. Am J Clin Nutr. 2007 Apr;85(4):1023-30. [Medline] PURPOSE: To examine the effects of 2 macronutrient patterns with different glycemic loads on adherence to calorie restriction (CR), weight and fat loss, and related variables. METHODS: A randomized controlled trial (RCT) of diets with a high glycemic load (Hg) or a low glycemic load (LG) at 30% CR was conducted in 34 healthy overweight adults with a mean age of 35 and BMI of 27.6. All food was provided for 6 months in controlled diets, and subjects self-administered the plans for 6 additional months. Outcomes included energy intake measured by doubly labeled water, body weight and fatness, hunger, satiety, and resting metabolic rate. RESULTS: All groups consumed significantly less energy during CR than at baseline. Changes in energy intake, body weight, body fat, and resting metabolic rate did not differ between groups. Both groups ate more energy than provided. Percentage weight change at 12 mo was -8.04% in the HG group and -7.81% in the LG group. There was no effect of dietary composition on hunger, satiety, or satisfaction with the amount and type of provided food during CR. CONCLUSION: These findings provide more detailed evidence that diets differing substantially in glycemic load induce comparable long-term weight loss. SPONSORSHIP: A grant coordinated by the National Institutes of Health. O

perational Definition of Glycemic Index (GI)

GI is a measure of ability of a fixed amount (50g) of, or “available” (non-fiber) carbohydrate within a food source (regardless of portion size) to raise blood sugar over a 3-hour period. The area under the response curve is calculated, and bam, there’s the GI. Multiple factors can alter GI and challenge its relevance – especially in the big picture, as the present trial demonstrates. For more detail on the inherent confounders of GI, efer to this r article.

O

perational Definition of Daily Glycemic Load (GL)

The daily GL in this trial was calculated as: [daily GI x the day’s total available carbohydrate in grams/1000 kcal]. Just as above, the amount of available carbohydrate for each food was calculated as total grams of carbohydrate minus total dietary fiber. S

tudy Strengths

This is a monster of a trial. By that, I’m not referring to the number of participants (even though that was appreciable). Nearly everything was tightly controlled, and this was a major undertaking considering that a high degree of micro-management of the subjects occurred for 12 months. The strength of this trial that distinctly separates it from others is its rigorous control of the subjects’ dietary intake. All food for the first 6 months was provided by the lab. Even during the 2nd 6 months of the trial, high measures of control were imposed. Subjects worked with a dietitian to develop an individualized plan

that included menus, recipes, portion sizes, and food lists that were consistent with their diets. Food scales were provided to control portions, and the subjects even attended a grocery store tour and a cooking class. The study was independently monitored for overall compliance and data accuracy by an external clinical trial monitor. Baseline weight-maintenance energy requirements were measured by doubly labeled water, which involves determining the turnover of two isotopes in order to arrive at the amount of CO2 produced, and from that, energy expenditure can be calculated (there’s decent tutorial on DLW on page 281). When snooping for dietary design flaws, I immediately check for protein insufficiency in at least one of the groups – this was not the case here. Both treatments provided adequate protein. Another common limitation is the absence of an exercise program, but then again, that limitation tends to be specific to the readership of this research review. For the sedentary folks who make up the majority of the industrialized world, the absence of a structured training protocol might actually be more applicable. A limitation common with larger, longer trials – especially ones involving caloric restriction – is dropout (attrition). This trial retained 85% of its starting participants, so dropout was not a major issue, nor was sample size. Study Limitations This is going to be a stretch, since this is one of the most tightly controlled, meticulously executed RCTs I’ve ever come across. So, in the spirit of groping for study limitations, I have a minor issue with the choice of instrumentation for body composition analysis: air displacement plethysmography (ADP), which goes by the trade name Bod Pod. In my quest to pick a bone with ADP, I found several studies implying that it’s on par with the validity and reliability of DEXA and hydrodensitiometry. However, breaking research found that variations in clothing tightness cause significant error in ADP readings, a factor that can either alleviate or worsen the error depending on the individual’s degree of excess bodyweight. Obese folks in spandex experienced the greatest error. T-shirt and shorts, or scrubs would be best for this population. If the initial phase of the present trial could be re-done, this data would serve as an important guide to properly matching clothing fit and bodyweight in order to minimize error. Comment/Application The high-GL diet was 60%C, 20%P, 20%F, with high-GI carb sources. The low-GL diet was 40%C, 30%P, 30%F, with low-GI carb sources. Popular media trends would lead most to predict the folly of the high-GL diet without hesitation. But, not only was there no difference in hunger, satiety, fat loss, and weight loss – there was actually a beginning of a trend toward weight re-gain in the low-GL group. To quote the authors, “Taken together, these findings suggest that reduced energy intake may be somewhat harder to sustain with the LG group in the long term.” The authors go on to conclude that, “…the present results suggest that a broad range of healthy diets can successfully promote weight loss.” On this point I agree, but I would also add that in my observations, caloric deficits offer a lot of leeway – more leeway than caloric surpluses for muscle gain. The subjects in this trial were in a 30% caloric deficit, so fudging carbohydrate and fat one way or the other wouldn’t make much difference as long as protein is adequate.

Alan Aragon’s Research Review, February, 2008                                  [Back to Contents]                  Page 15 

Master Amino Acid Pattern (MAP) provides a sure way to rebuild energy – fitness – life! [BodyHealth] A competitive triathlete client of mine asked me to check this article out and give him my two cents. Well, I might as well spread the wealth. On their “About Us” page, BodyHealth is anonymous. There are no faces to associate with the company. No founder, no president, no staff listing, nothing. Yet, they claim to have started in March of 2000, marketing supplements o doctors. Here’s what appears to be their core cause: t

Okay, sounds noble and medical enough. It’s obvious that this is simply a supplement sales operation, but let’s take a look at some of the elements that may have led my new (at the time) client to ask me to have a look... For starters, there’s the champion triathlete endorsing the product with a manufactured-sounding testimonial with the product’s name in bold. The product in question is MAP, formerly called Biobuilde. It’s nothing more and nothing less than an essential amino acid (EAA) supplement, but the guys at BodyHealth have found a brilliant way to market it as a sports panacea to the lay public. Their campaign? Simple, keep the professional triathlete testimonials in place, and make all other protein sources appear completely useless. Make sure to “blind” the consumer with scientific jargon such as “net nitrogen utilization (NNU)”, then emphasize that all-important acronym – NNU. Because you see, MAP has the highest NNU of anything on the planet, which means that virtually none of it gets wasted, unlike other amino acid sources in your diet wrapped up in this dreadful complex called “food” which renders it... Toxic Nitrogen Waste. Here’s the chart that gave me an instant education in the art of BULL: Just think, that right there is the pinnacle of someone’s graphic design career... Okay, enough poking fun, this is serious business. Without even pondering the claims that are misleading to the point of blasphemy, I look for the price of this EAA

supplement. I can’t find it. I keep looking, give up, do a Google search. It’s not a red flag or anything when prices of a product aren’t even listed on the site. There was an option to register my email address, and I think I would have gotten access to the prices, but I didn’t have the energy that day. Anyway, the search turned up a few sources that listed prices in the neighborhood of 55 bucks plus shipping for (get ready for this) 120 tabs, each tab is a gram. This amounts to a little over a quarter of a pound of EAA, for about 60 bucks when you count shipping. I explained to my client that for 60 bucks, you can go wild and get 5 lb of whey isolate. That translates to 2270 grams of protein, half of which is EAA – 1135 grams. So when you compare 120g EAA from BodyHealth for the price of 1135g EAA from whey (nevermind the other 1135g protein in & other goodies) you begin to realize why I wanted to share this little story.

Our mission is to educate doctors and the public with the correct know-how and products to improve the body's condition, and to provide them with the products needed to do that.

Indeed, I eventually called BodyHealth and asked them for some research backing up their claims. The sales rep sounded like an honest, hard working, warm-hearted person, so I sort of feel like I’m taking advantage of this situation. Damn that conscience of mine. To my surprise, she sent me at least a couple of studies that supposedly support their “Master Amino Acid Pattern” EAA product. I’ll have them laid out for you next month, gotta do it right and keep an open mind. They might be on to something. In addition to reviewing the current and past-yet-juicy studies, I’ll wrap up the theory and practice of protein and carbohydrate timing with post-exercise nutrition. In the mean time, I’ll be endlessly navigating my way through the waxy maze of info. I’m open to suggestions, comments, questions, and civil debate (letters to the editor). Send your correspondence to aarrsupport@gmail.com. Until next month, enjoy the Feb’ love. “In some instances, statistically significant results may not be clinically important and, conversely, statistically insignificant results do not completely rule out the possibility of clinically important effects.” – Chan KBY, et al. 2001