Living Healthy: Tools for Successful Weight LossWayne Larsen CSCSB.S. Exercise and Sports ScienceUniversity of Utah
Overview:Americas obesity epidemicMetabolism and energy balanceSuccessful weight loss what really works?The role of aerobic exerciseApplying the FITT principle to weight lossDebunking a few myths!
Americas Obesity EpidemicCDC stats on obesity:1960: 13.4% of Americans 1999-2000: 30.9% of Americans Affects 1 in every 3 adults, 1 of every 6 children Health RisksType II diabetesHypertensionHigh cholesterolHeart diseaseGall bladder diseaseOsteoarthritisRespiratory problemsSome cancersHerniasVaricose veinsComplications in surgery/preg
So What Happened?No one decides to become overweight!Most weight gain is result of complicated changes in our environment:Calorie-dense food more readily availableOpportunities for physical activity are lackingStress and other emotional triggers to eat are highOur goals:Increase awareness of these problemsFind workable solutionsIndividual responsibility- chose to act rather than be acted upon!
- Causes? Physical inactivityModern technology has dramatically decreased the necessity to moveBusy lifestyles make time more and more scarceCycle of deconditioning/fatigue makes exercise less and less appealingEstimates are that
It all comes down to energy balance!While many factors contribute to obesity, ultimately a positive caloric balance is the cause.
Positive energy balanceKcals in > (RMR + Activity + TEE)
Negative energy balanceKcals in < (RMR + Activity + TEE)
Balancing the energy equation:So how many calories should I take in?
Energy Out: your daily expenditure
3-D Pie 1
Contributors to Daily Caloric Needs
Activity (20-30%)Resting Metabolic Rate (60-70%)Thermic Effect of Food (10%)
3-D Pie 1306010
Energy Out: your daily expenditureResting Metabolic Rate (RMR)Kcals/day at quiet restLean body mass (muscle) is most significant determinant of RMRVery low calorie diets reduce metabolic rateRMR tested by measuring resting O2 uptake Can be estimated using prediction equations
Energy Out: your daily expenditurePhysical ActivityMost variable AND changeable!Includes structured exercise, lifestyle activities, and involuntary movement (i.e. fidgeting)Increases RMR by 25-40% Significant in weight gain/loss!
Energy out: your daily expenditureThermic effect of foodEnergy required to digest, absorb, process foodApprox. 10% above total energy consumedFat is far less thermogenic than carbohydrateProtein is more thermogenic than carbohydrate
Set-Point TheoryThe set-point is a kind of thermostat for fat -set at higher levels for some, and lower for others. Each persons set-point is defended by hormones that dictate hunger and metabolism.
The body cannot tell the difference between dieting and starvation; long term caloric deprivation signals the body to turn down its metabolic rate to maintain the set-point. Calories are burned more efficiently, so even a stringent diet may not elicit weight loss.
Exercise is the only known way to re-set this internal thermostat, and LOWER ones set-point.
Successful Weight Loss =Aerobic Exercise PLUSStrength Training PLUSSound nutrition PLUSBehavior modification
RESULT: A NEW LIFESTYLE
How to determine my ideal body weight? (and is there such a thing?!?)Advantages of body composition measurementMeasure fat mass and fat-free massAccounts for differences in denser tissues like bone, muscleProportion (and distribution) of fat is link to health risksAllows for healthy and realistic weight loss goals to be set
Methods for measuring body compositionSkinfoldsBioelectrical impedanceUnderwater weighingDXA (dual x-ray absorbtiometry)The gold standard measureEasy, comfortable to useQuantifies fat and lean componentsTracks regional changes in fat and lean tissue, as well as whole body
How to determine my ideal body weight? (and is there such a thing?!?)Health goals vs. appearance goals do they coincide.?Being thin doesnt guarantee health Being heavier doesnt have to be unhealthyEven a small weight loss (10% of body wt) can significantly decrease health risks
Physical activity and cardiovascular fitness are much more predictive of health than body weight
Applying the F.I.T.T. Principle to Weight LossFrequency: > 5 days per weekHigher freq. = increased caloric deficitCross-train to minimize boredom and risk of overuse injuryLower freq. needed to maintain a given level of fitness than to attain it
The F.I.T.T. Principle and Weight LossIntensity:Initial intensity moderate, or HR of 50-70% Progress to vigorous, or HR of 70-80%
But dont I need to keep my heart rate in the 50-70% fat burning zone to lose weight?!?
Myth #1: The Fat Burning ZoneFact: A higher percentage of calories from fat are used at lower intensitiesFact: Even though the percentage of calories from fat decreases with increased exercise intensity, the absolute number of fat calories rises.Fact: You dont have to BURN fat to LOSE fata calorie burned is one less stored as fat!
Interval TrainingInterval training refers to mixed-intensity exercise.Intermittent, harder efforts (70-90%) of10 sec.-3 min. mixed in with exercise performed at a more comfortable paceInterval training aids weight lossBurns more calories within the same time period than does steady-state exerciseInterval training creates a greater post-exercise caloric burn, Keeping metabolism elevated longer.Anyone can do interval training.Not just for athletesWork/rest ratios can be self-determined based on RPEIntervals can be done in any exercise mode
Applying the F.I.T.T. Principle to Weight LossTime: how long should I exercise?ACSM: 20-60 min/day150 min. per week for weight lossData support threshold of 200 min./week as most effective (National Weight Loss Registry)10 min, 2-3x/day confers same health benefits as continuous exWhen it comes to weight loss/maintenance, more is better!
Intensity vs. Duration: which is more important?
Inverse relationship between intensity and durationIn early stage (base-building phase), duration is more important than intensityBuild duration gradually (
Myth #2: Working out in the morning means I can relax the rest of the dayTermed compensation in weight loss researchCompensating means the caloric deficit created during exercise is rendered ineffective by decreased activity through the rest of the dayFact: the small activities of daily life add up to significant calories burnedFact: the less you can sit during the day, the betterFact: fidgety people are rarely overweight!
Applying the F.I.T.T. Principle to Weight LossType of exercise (mode)What is the best exercise for weight loss???
The Answer:The one(s) you will DO! JVary your routine oftenMake it social!Try NEW stufftake risks!!Find something you ENJOYSet a GOAL.dream big!
Other Considerations:Orthopedic conditions WeatherSkillAccessibility/convenience
Two more myths.....Exercise will increase my appetite and make me eat more!
FACT: Most report a decrease in appetite, and an increased awareness of fullnessFACT: eating more may not be bad, it food CHOICE is better
It takes too much exercise to burn a significant number of calories its easier to just eat less
FACT: A 30 min session of exercise may only burn 300 caloriesFACT: Even at only 3-4x/wk, over a year creates a 13-23 lb lossFACT: Exercise becomes more effective as fitness level increases:Increased exercise tolerance: ability to burn more calories before fatigueImproved fat metabolism: adaptations that increase ability to burn fat Increase in post-exercise metabolic rateIncrease in resting metabolic rate: relative to increases in lean mass