Protein Requirements for Athletes…

Beyond Daily Targets

Gary Slater PhD

Senior Lecturer (Masters of Sports Nutrition)

University of the Sunshine Coast

National Performance Nutrition Coordinator ARU

Overview of Session

• Factors to consider…

– Energy budget

– Protein distribution

– Protein dose

– Protein source

• Amino acid profile

• Digestion rate

• Intake during exercise

• Health implications

Protein Requirements

Group

Protein Intake (g.kg-1.day-1)

Male Female

Sedentary males & females 0.8 - 1.0 0.8 - 1.0

Recreational endurance athletesa 0.8 - 1.0 0.8 - 1.0

Moderate intensity endurance athletesb 1.2 1.0

Elite male endurance athlete 1.6 1.4

Resistance athletes (early training) 1.5 - 1.7 1.3 - 1.5

Resistance athletes (steady state) 1.0 - 1.2 1.0

Football, power sports 1.4 - 1.7 1.2 - 1.5 aExercising 4-5.wk-1 for 30 min. @ < 55% VO2 peak

bExercising ~ 4-5.wk-1 for 45 – 60 min.

Clinical Sports Nutrition (4th ed.) 2010.

Muscle Protein Turnover

Little & Phillips. Appl Physiol Nutr Metab. 34:817-826, 2009.

Mu

scle

Pro

tein

Ba

lan

ce

I

II

AA/Leucine

± CHO

AA/Leucine

± CHO

Fed state gains (I) = Fasted state losses (II)

Muscle Protein Turnover

Little & Phillips. Appl Physiol Nutr Metab. 34:817-826, 2009.

Fed state gains (I+III) > Fasted state losses (II-IV)

AA/Leucine

± CHO

AA/Leucine

± CHO

Mu

scle

Pro

tein

Ba

lan

ce

Resistance Exercise

I

II

III

IV

Muscle Protein Turnover

Phillips et al. Am J Physiol 273:E99-E107, 1997.

Protein Synthesis

Protein Breakdown

Rather than the age-old debate regarding overall protein & amino acid needs of athletes, focus should be given to the importance of timing & type of protein & amino acid ingestion relative to both muscle

growth & exercise performance. Recent data indicate that consuming a small meal of mixed macronutrient composition following strength exercise bouts can alter significantly net protein

balance, resulting in greater gains in both muscle mass & strength than observed with training alone. With aerobic exercise, some evidence suggests immediate post-exercise supplementation is also beneficial. Second, protein type may also be important owing to variable speeds of absorption &

availability, differences in amino acid and peptide profiles, unique hormonal response, or positive effects on antioxidant defence. In addition to athletes, many others who desire to regain, maintain, or

enhance muscle mass or function need to ensure that nutrient availability is sufficient during the apparently critical anabolic window of time associated with exercise training sessions.

Lemon et al. Curr Sports Med Rep. 4:214-21, 2002.

Lemon et al. Curr Sports Med Rep. 4:214-21, 2002.

• When reviewing protein needs of athletes, consider desired outcomes as well as…

– Total energy intake

– Distribution of protein intake

– Individual protein dose

– Protein source

Overview of Session

• Factors to consider…

– Energy budget

– Protein distribution

– Protein dose

– Protein source

• Amino acid profile

• Digestion rate

• Intake during exercise

• Health implications

Protein Requirements

• Optimisation warranted for wide range of athletes & specific goals – Strength, endurance

– Fat loss, muscle gain, optimal recovery

• When assessing protein intake, consideration must be given to… – Training undertaken & desired outcomes

– Energy budget (& thus co-ingestion of other nutrients)

– Distribution of protein throughout the day • Include a small serve at each meal & snack

– Individual doses of protein at meals & snacks • 15-30g+ (0.3g·kg-1) for majority of athletes, slightly higher for older athletes

• Upwards of 50g if satiety is priority

– Source of protein • Rapidly digested HBV proteins rich in Leucine should be a priority • Emphasize nutritious protein rich foods, achieving overall nutrient needs • If using protein supplements, allocate use to periods where you’ll get

‘maximum bang for your buck’ & limit to <1-2 serves a day