Nutrition 101: The Art of Balancing Energy Intake for Body Composition and Performance.

Nutrition 101: The Art of Balancing Energy Intake for Body Composition and Performance.

Eric Helms, MS, MPhil, CSCS, USAW L1

  • Once you’ve established maintenance calories, you can set up your energy intake based on appropriate rates of weight loss or gain, depending on your goal.
  • Fat loss can occur at a faster rate than muscle gain, so you should use slower rates of weight gain for muscle building compared to weight loss for fat burning.
  • For weight loss, set your calories to achieve a weekly deficit resulting in a loss of 0.5-1.5% of your bodyweight per week, scaled with body fat (1.5% if it is high).
  • For weight gain, set your calories to achieve a surplus resulting in a monthly gain of 0.5-1.5% of your bodyweight, scaled inversely to training age (0.5% for advanced).
  • Once you’ve established calories, then you can break them up into macronutrients to ensure a diet balanced for body composition and performance optimization.


Once you understand the relationship between energy balance and body composition change as discussed here, the next step is to take your maintenance energy requirement and use it to determine an appropriate caloric intake for your goals. For weight loss, losing weight at a rate of 0.5 to 1.5% of body weight per week minimizes muscle and strength loss [1-3]. The primary factor that dictates where you should fall within this range is your relative body composition. Individuals with higher body fat levels can safely lose weight at a faster rate as they can liberate more body fat for energy. Leaner individuals cannot liberate as much body fat and thus, risk lean tissue loss when attempting to lose weight too quickly [4].


Therefore, an easy rule of thumb is to target a 1.5% if you are high in body fat (20%+ for men and 28%+ for women), 1% if you are of an average body fat (12-19% for men and 20-27% for women), and 0.5% if you are lean (under 12% for men and 20% for women). So how does this tie in with energy balance? If you recall the ‘3500 calorie rule’, you know a 500 kcal deficit per day results in a 3500 kcal deficit per week, which equates to a pound of fat loss. In the case of a relatively large 200 lbs man, 1 lb is 0.5% of his bodyweight. For a relatively slight 100 lbs woman, 1 lb is 1% of her bodyweight. Thus, set up a target weekly deficit relative to your bodyweight to achieve the weekly rate of weight loss appropriate for your body fat level, between 0.5-1.5% weight loss per week.


Although this seems like simple math, it doesn’t always work out that way. Energy expenditure adjusts according to energy balance. To some degree, your energy output decreases in response to caloric restriction. This occurs via reductions in subconscious activity, lowered thermic effect of food from eating less, increased muscular efficiency, lowered body mass burning fewer calories, and potentially a temporary drop in metabolic rate beyond that predicted by weight loss [5-8]. Therefore, once you have established your calories, you will have to monitor weight loss (using the 7-day average method I discussed in the last article) and adjust energy intake when you fall below your target weight loss rate.


For gaining muscle and strength, the guidelines are a bit different. As I discussed in the last article, despite the difference in the energy contained in muscle vs body fat, the ‘3500 kcal rule’ works for setting your calories for muscle gain as well. What differs, are the appropriate rates of weight gain vs. weight loss. A recent 12-week study comparing rates of weight gain in resistance-trained athletes found that the group consuming a small surplus gained the same amount of muscle and strength, but only one fifth the body fat as the group that consumed an additional 600 calories [9]. When extrapolating the rates of weight gain in this study into practical recommendations, gaining weight at a rate of 0.5-1.5% of your bodyweight seems to be just as effective for gaining muscle and strength as going faster, while minimizing fat gain. But there is a catch; unlike the weight loss rates being per week, this is rate of gain per month!


While weight loss rate was dictated by body fat level, rate of weight gain is determined by how long you’ve been lifting weights and how much of your muscular potential you’ve realized.  To establish rate of weight gain, we differentiate within the range of 0.5-1.5% of your bodyweight per month, based on training age. Beginners can gain 1.5% of their bodyweight per month without excessive fat gain, intermediates at 1%, and advanced lifters at 0.5%. However, when dealing with slow rates of gain like this, it doesn’t make sense to check 7 day averages anymore. It’s better to simply set the small surplus, and look at your averages over large time periods, like month to month. Remember, it’s the tortoise vs the hare.


This might shock you, I know the typical muscle magazine tells you to gain 1lb a week. However, I can tell you from not only the empirical data I just presented, but also having coached hundreds of drug free bodybuilders, that gaining at that speed will quickly result in you gaining a lot of body fat without a substantial increase in muscle mass relative to going slower. That doesn’t mean there is never a time to gain relatively quickly, it just depends on your capacity to gain muscle.


Finally, remember from Dr. Fitschen’s article that macronutrients are where calories come from. To maximize muscle gain, consume a minimum protein of 1.6g/kg or ~0.75g/lb of bodyweight [10]. There is no health risk associated with eating more, in fact it may minimize excess fat gain, since protein is highly satiating and its thermic effect is higher than other macronutrients [11]. However, this can be a double-edged sword for those who struggle to gain weight. If you are trying to lose weight, you want a higher intake to ensure satiety [12], to add slightly to energy expenditure [13] and theoretically to offset some of the potential muscle mass loss that can occur when dieting [14]. A minimum protein intake of 1.8g/kg or 0.8g/lb is suggested while in a caloric deficit and no higher than 2.8g/kg or 1.3g/lbs to ensure fat and carbohydrate intakes aren’t forced too low [15].


For fat and carbohydrate, the specific gram amount has a lesser impact on both fat loss and muscle gain compared to protein. Thus, consider your personal preferences when setting these targets to maximize your adherence [16]. However, be diligent to ensure you are consuming adequate fat for normal physiological function, and carbohydrate to maintain performance. To do so, set fat intake in the range of 20-35% of total daily calories; which can be determined by multiplying caloric intake by 0.2-.35 (divide this number by 9 to get grams). Then take away your daily calories of fat and protein from your total daily calories to find your calories left for carbohydrates [17]. Simply divide this last calorie amount by 4 to determine the grams. As a final note based on my experience working with clients, you should avoid going below 0.25g/lb for your fat intake, which can occur with a low-calorie target and the lower end of the percentage of calories from fat range. Likewise, avoid going below 0.5g per pound of carbohydrate. Remember, your diet should support both your training and health while being sustainable.




  1. Mero, A.A., et al., Moderate energy restriction with high protein diet results in healthier outcome in women. Journal of the International Society of Sports Nutrition, 2010. 7(1): p. 4.
  2. Garthe, I., et al., Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab, 2011. 21(2): p. 97-104.
  3. Turocy, P., et al., National Athletic Trainers’ Association position statement: safe weight loss and maintenance practices in sport and exercise. Journal of Athletic Training, 2011. 46: p. 322 – 336.
  4. Forbes, G.B., Body fat content influences the body composition response to nutrition and exercise. Annals of the New York Academy of Sciences, 2000. 904(1): p. 359-65.
  5. Doucet, E., et al., Evidence for the existence of adaptive thermogenesis during weight loss. Br J Nutr, 2001. 85(6): p. 715-23.
  6. Rosenbaum, M., et al., Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight. American Journal of Clinical Nutrition, 2008. 88(4): p. 906-12.
  7. Rosenbaum, M. and R.L. Leibel, Adaptive thermogenesis in humans. Int J Obes (Lond), 2010. 34 Suppl 1: p. S47-55.
  8. Camps, S.G., S.P. Verhoef, and K.R. Westerterp, Weight loss, weight maintenance, and adaptive thermogenesis. The American Journal of Clinical Nutrition, 2013. 97(5): p. 990-994.
  9. Garthe, I., et al., Effect of nutritional intervention on body composition and performance in elite athletes. European journal of sport science, 2013. 13(3): p. 295-303.
  10. Fielding, R.A. and J. Parkington, What are the dietary protein requirements of physically active individuals? New evidence on the effects of exercise on protein utilization during post-exercise recovery. Nutrition in Clinical Care, 2002. 5(4): p. 191-6.
  11. Paddon-Jones, D., et al., Protein, weight management, and satiety. Am J Clin Nutr, 2008. 87(5): p. 1558S-1561S.
  12. Helms, E.R., et al., High-protein, low-fat, short-term diet results in less stress and fatigue than moderate-protein moderate-fat diet during weight loss in male weightlifters: a pilot study. Int J Sport Nutr Exerc Metab, 2015. 25(2): p. 163-70.
  13. Antonio, J., et al., A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women–a follow-up investigation. J Int Soc Sports Nutr, 2015. 12: p. 39.
  14. Phillips, S.M. and L.J. Van Loon, Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci, 2011. 29 Suppl 1: p. S29-38.
  15. Helms, E.R., et al., A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab, 2014. 24(2): p. 127-38.
  16. Johnston, B.C., et al., Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis. JAMA, 2014. 312(9): p. 923-33.
  17. Helms, E.R., A.A. Aragon, and P.J. Fitschen, Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 2014. 11(1): p. 20.
Eric Helms
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