What body recomposition is
Body recomposition ("recomp") means losing fat and gaining muscle at the same time, so your shape and strength change more than the scale does. Instead of a big deficit, you eat at or a little below maintenance, eat plenty of protein and lift weights with progressive overload. This calculator gives the calorie and protein targets for that approach.
How it's calculated
Maintenance = BMR × activity factor
Target = maintenance − 0, 250 or 400 kcal
Protein = 1.4 to 2.0 g × body weight in kg
The activity factors (1.2 to 1.9) are the same ones the TDEE calculator uses. The protein range is from the International Society of Sports Nutrition (ISSN) position stand, which says 1.4–2.0 g per kg a day "is sufficient for most exercising individuals". It also notes newer evidence that intakes above 3.0 g/kg may help body composition in resistance-trained people.
Why a small deficit
A 2022 meta-analysis of resistance training studies (Murphy and Koehler) found that eating in an energy deficit held back lean mass gains, but not strength gains. Its meta-regression found that a deficit of about 500 kcal a day prevented lean mass gains. So this calculator only offers deficits well under that, and maintenance. The 250 and 400 kcal steps are Calcist's choices, not values from a study.
The Physical Activity Guidelines for Americans advise muscle-strengthening activity at least 2 days a week for adults. Recomp depends on that training; diet alone won't build muscle.
Worked example
A 30-year-old man, 180 cm and 80 kg, moderately active:
Maintenance = 1,780 × 1.55 = 2,759 kcal
Small deficit: 2,759 − 250 = 2,509 kcal a day
Protein: 80 × 1.4 = 112 g to 80 × 2.0 = 160 g a day
Who it works best for
Recomposition is most often expected in people who are new to lifting or getting back into it, and in people with more body fat. A 2020 review (Barakat and colleagues) notes that this is the common view, and also gathers studies showing recomp in resistance-trained people, with progressive training and good nutrition as the two key factors. In one trial, young men in a large (40%) deficit who did intense training 6 days a week gained 1.2 kg of lean mass and lost 4.8 kg of fat on 2.4 g/kg of protein, compared with 0.1 kg gained and 3.5 kg lost on 1.2 g/kg (Longland and colleagues, 2016). That was a 4-week study, so it's a short-term result.
Limitations
- Maintenance is an estimate and can be off by 10% or more. Watch your weight, waist and strength for a few weeks and adjust.
- Progress is slower than a plain cut or bulk, and the scale may barely move. Measurements, photos and strength logs show it better.
- For a high body fat percentage, total body weight can overstate protein needs.
- Not for pregnancy, breastfeeding, children or teens, or people with kidney disease, who may need a set protein limit.
- Calcist won't suggest a deficit that takes intake below 1,200 kcal (women) or 1,500 kcal (men), the lower levels the NHLBI guidelines describe for low-calorie diets.
Sources
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241–247.
- Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20.
- Murphy C, Koehler K. Energy deficiency impairs resistance training gains in lean mass but not strength: a meta-analysis and meta-regression. Scand J Med Sci Sports 2022;32(1):125–137.
- Barakat C, et al. Body recomposition: can trained individuals build muscle and lose fat at the same time? Strength Cond J 2020;42(5):7–21.
- Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. Am J Clin Nutr 2016;103(3):738–746.
- U.S. Department of Health and Human Services: Physical Activity Guidelines for Americans, top 10 things to know
- NHLBI: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults (1998) — the 1,200 and 1,500 kcal levels used as floors.