Body Recomposition Calorie Calculator
Create a transparent starting reference for calories, protein and resistance training—then calibrate it with your own consistent logs. It does not predict your body composition or promise a timeline.
A plan that leaves room for observation
Get calorie, protein and training references, then use the 14-day check-in to see what your own logs show.
Method & evidence
How this body recomposition estimate is calculated
This tool creates a cautious starting reference, not a prediction of fat loss or muscle gain. It combines a validated resting-energy equation with transparent product assumptions, then keeps the important feedback loop in your own 14-day log.
01
Estimate resting energy
Mifflin–St Jeor uses age, sex input, height and weight.
02
Set a calorie starting point
Selected activity estimates maintenance; balanced mode uses it directly.
03
Add protein & training references
Weight-based protein and a two-session resistance-training floor provide context.
Formula and activity estimate
Resting kcal/day = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for the male equation, or −161 for the female equation. The calculator multiplies that value by the selected activity factor. Mifflin's study supports the resting-energy equation; it does not validate an activity factor or personal maintenance target. [1]
Calories and the conservative adjustment
Balanced mode displays estimated maintenance. Fat-loss-biased mode subtracts the smaller of 10% of that estimate or 250 kcal/day. This cap is deliberately smaller than the roughly 500 kcal/day deficit associated with no lean-mass gain in one resistance-training meta-regression; it is not evidence that 250 kcal or 10% is optimal for you. [2]
Protein and resistance training
The tool shows 1.4–2.0 g/kg/day and highlights 1.6 g/kg/day. A meta-analysis found average resistance-training benefit plateaued around 1.6 g/kg/day, while the ISSN position stand describes 1.4–2.0 g/kg/day as sufficient for most exercising people. Neither makes the highlighted number a universal requirement. [3] [4]
The training reference starts with two weekly resistance sessions for major muscle groups. Higher frequency can help when volume is matched, but split and full-body routines do not show a universal winner; consistent, recoverable work matters more than the label. [5] [6]
Body-fat input and 14-day check-in
If entered, body fat only produces descriptive fat and fat-free mass estimates; it does not alter energy targets. Consumer methods can be imprecise. A stable scale alone cannot prove simultaneous fat loss and muscle gain. Review logs, training, recovery, photos or measurements consistently before adjusting a plan.
Who should use individualized guidance?
This adult estimate is not for children, pregnancy, breastfeeding, eating-disorder recovery, kidney disease, diabetes medication adjustment, illness recovery, or other clinical circumstances. Consult a qualified clinician or dietitian when those apply. The calculator is local, uses no AI, and does not save or transfer results to Shelog.
References & what they support
- Mifflin MD et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. Supports resting-energy estimation only.
- Murphy CH, Koehler K. (2022). Energy deficiency impairs resistance training gains in lean mass. Supports the limitation around larger deficits, not this tool's cap.
- Morton RW et al. (2018). Protein supplementation and resistance training meta-analysis. Supports the 1.6 g/kg/day context.
- Jäger R et al. (2017). ISSN position stand: protein and exercise. Supports the exercising-adult range context.
- Schoenfeld BJ et al. (2016). Resistance-training frequency meta-analysis. Supports the two-sessions-per-week reference.
- Schultz et al. (2024). Split versus full-body resistance training meta-analysis. Supports avoiding a universal split recommendation.
Disclaimer: This is an adult estimate, not medical or individualized nutrition advice. Consult a qualified professional for clinical conditions or a personal plan.