Energy Density012345678910Carbohydrate Protein Fat Alcoholkcal/gMacronutrient
Estimating Energy Expenditure• Revised Harris-Benedict Formula1– Basal metabolic rate (BMR)– Activity factor (AF)– Total daily energy expenditure (TDEE)
Estimating Energy Expenditure• Revised Harris-Benedict Formula1– Men• BMR = 88.362 + (13.397 x weight in kg) + (4.799 xheight in cm) - (5.677 x age in years)– Women• BMR = 447.593 + (9.247 x weight in kg) + (3.098 xheight in cm) - (4.330 x age in years)
Estimating Energy Expenditure• Revised Harris-Benedict Formula1– TDEE = BMR x AF• Little to no exercise Daily kilocalories needed = BMR x 1.2• Light exercise (1 – 3 days/week) Daily kilocalories needed = BMR x 1.375• Moderate exercise (3 – 5 days/week) Daily kilocalories needed = BMR x 1.55• Heavy exercise (6 – 7 days/week) Daily kilocalories needed = BMR x 1.725• Very heavy exercise (twice/day, max ex) Daily kilocalories needed = BMR x 1.9• Pregnancy Daily kilocalories needed = +300• Lactation Daily kilocalories needed = +500
Energy Expenditure• Resting metabolic rate (RMR)2– 60 – 75% daily energy expenditure• Thermic effect of activity (TEA)2– 15 – 30% daily energy expenditure• Could be even higher in extremely active individuals• Thermic effect of feeding (TEF)2– ~10% daily energy expenditure
Macronutrient Contributions• A well balanced diet should consist of thefollowing macronutrient percentages– Ranges vary for individual demands/goals• CHO 55 – 65%• PRO 15 – 25%• FAT 15 – 25%*Per day, not per meal necessarily
Diet Analysis• Female, 22 years old, 120 lbs, 5’3”– BMR = 1,352.4– AF = 1.375 (light exercise; 1 – 3 days/week)– TDEE = 1,352.4 x 1.375 = 1, 860 kcal60% CHO1,116 kcal279 g20% PRO372 kcal93 g20% FAT372 kcal41 g
Low CHO Diet• Glycogen– Stored CHO– Extremely important energy substrate– Requires water retention• 2 – 4 g of water/1 g CHO3-5– Low CHO diet = ↑ water loss
Low CHO Diet• Insufficient CHO intake leads to depletedglycogen, blood glucose– Brain, nerves, blood, are fueled by CHO• Fat cannot be converted directly to glucose• Glucose is then created via non-idealpathways– Glycerol from triglycerides– Muscle degraded to create CHO
Low CHO Diet• Fat breakdown is dependent on CHO presence• ↓CHO↓ pyruvate↓ TCA cycle intermediates↓ TCA cycle↓ fat catabolism• “Fat burns in a CHO flame”
Low CHO Diet• ↑ protein↑ nitrogen↑ deamination↑ ammonia↑urea↑ water lossCarbohydrate: C-H-OProtein: C-H-O-N
Low CHO Diet• Protein is a horrible energy source• Only a small contribution (~2%) to totalenergy production during exercise6– May increase to 5 – 15% late in prolonged-duration exercise
Low CHO Diet• Diuretic• Depletes glycogen• Promotes incomplete fat mobilization• Promotes muscle degradation• Promotes central fatigue• Potentially high in saturated fat, fat• Potentially low in micronutrients, fiber• Potentially costly
Low CHO DietHigh PRO761.2%35.0%3.8%Mixed737.1%59.5%3.4%Starvation760.9%32.4%6.7%W:F:P:
Energy Expenditure• Thermic effect of feeding (TEF)– More meals = increased energy expenditure?• False8-10• Likely helps curb cravings, hunger though
Calorie Shifting• Keep your body/metabolism guessing?– Anecdotal and no real research, however…• Could be used as a good base– Don’t have to stress about calorie content of each meal• Could promote a well-rounded diet– Not eating the same foods• Should not use extremes
Underfeeding• Caloric decrease should be modest tomaximize weight loss, minimize hunger, andmaintain physiological functioning– ~500 kcal/day is generally suggested• Equates to 1 lb/week– Women should consume at least 1,200 kcal/day11– Men should consume at least 1,800 kcal/day11
Exercise• Easiest way to provide a negative energybalance– Cutting calories in the diet is not always an option– Typically cardiovascular exercise– Also weight training, interval training, etc.
Weight Loss• Weight loss is a gradual process• It takes ~4 weeks to establish the desiredpattern of fat loss for each pound of weightloss12
Resistance Training• Must overload/stress the body– Consistently• Muscle growth is gradual and highlyindividual14-16• 12 weeks (+/-) for untrained individual• Chronic resistance training typically leads to 0 – 1kg/month increase in fat-free mass
Overfeeding• Typically only 30 – 40% of weight gain is fat-free mass15,17-18• Caloric increase should be modest tomaximize muscle-to-fat gain– 300 to 500 kcal/day19– 55 – 60% should come from CHO19
Chocolate Milk• Nature’s engineered recovery beverage• Provides fluid• Cheap– ~$5/gallon (CA prices in 2013)• Serving– 1-2 cups depending on needs– ~$0.32/cup• CHO:PRO ratio– 3:1 – 4:1• For lower ratio (anaerobic) you can “cut” with plain milk or use less chocolate• For higher ratio (aerobic) you can add chocolate• Casein, whey protein 8-11 g/cup• High glycemic index 25-30 g/cup• Fat-free 0 g/cup• Low-fat 2.5 g/cup– Not ideal but a small amount of fat will likely not delay gastric emptying too significantly• Vitamins/minerals– Calcium, vitamin D, sodium, potassium, etc.
Supplements• Completely unregulated industry– Too much?– Too little?– Safe?– Purity?– Cost?– Adverse effects?– Spiked?– Tainted?– Contamination?– No research?– Bad research?– Research sponsor?– Marketing?
Sources1. Roza, A., et al. (1984). The Harris Benedict equation reevaluated. American Journal of Clinical Nutrition, 40(1), 168-182. 192. Poehlman, E. (1989). A review: Exercise and its influence on resting energy metabolism in man. Medicine and Science in Sportsand Exercise, 21(5), 515-525.3. Greenleaf, J., et al. (1969). Muscle glycogen and its significance for the water content of the body. Acta PhysiologicaScandinavica Supplementum.4. Kreitzman, S., et al. (1992). Glycogen storage: Illutions of easy weight loss, excessive weight regain, and distortions inestimations of body composition. The American Journal of Clinical Nutrition, 56, 292S-293S.5. Tymoczko, J., et al. (2009). Biochemistry: A short course.6. Powers, S., et al. (2011). Exercise physiology: Theory and application to fitness and performance.7. Yang, M. & Van Itallie, T. (1976). Composition of weight lost during short-term weight reduction. Metabolic responses of obesesubjects to starvation and low-calorie ketogenic and nonketogenic diets. The Journal of Clinical Investigation, 58(3), 722-730.8. Hill, J., et al. (1988). Effects of meal frequency on energy utilization in rats. American Journal of Physiology, 255, R616-R621.9. Wolfram, G., et al. (1987). Thermogenesis in humans after varying meal time frequency. Annals of Nutrition andMetabolism, 31(2), 88-97.10. Bellisle, F., et al. (1997). Meal frequency and energy balance. British Journal of Nutrition, 77, S57-S70.11. American College of Sports Medicine. (2005). Resource Manual for Guidelines for Exercise Testing and Prescription.12. McArdle, W., et al. (2010). Exercise physiology: Nutrition, energy, and human performance.13. Behnke, A., & Wilmore, J. (1974). Evaluation and regulation of body build and composition.14. Kraemer WJ. General adaptations to resistance and endurance training. In: Baechle T, editor. Essentials of strength training andconditioning. Champaign (IL): Human Kinetics, 1994: 127-5015. Forbes, G. (1991). Exercise and body composition. Journal of Applied Physiology, 70, 994-997.16. Wilmore, J. (1974. Alterations in strength, body composition, and anthropometric measurements consequent to a 10 weekweight training program. Medicine and Science in Sport and Exercise, 6, 133-138.17. Welle, S., et al. (1989). Stimulation of protein turnover by carbohydrate overfeeding in men. American Journal ofPhysiology, 257, E413-E417.18. Forbes, G., et al. (1986). Deliberate overfeeding in women and men: Energy cost and composition of weight gain. BritishJournal of Nutrition, 56, 1-9.19. Fink, H., et al. (2009). Practical Applications in Sports Nutrition.