Body Recomposition Planner
The fat to lose to reach a body-fat target, the daily deficit and weekly pace that gets you there on your timeline, and a protein target that protects muscle.
Result
Fat to lose × 7,700 kcal per kg, spread over the timeline, with lean mass held steady. Recalculate maintenance every few weeks: it falls as you lose weight.
Scale weight on this plan
Lean mass held steady; fat lost at an even pace.
How to use it
- Enter your current weight, current body fat percentage, the body fat you are aiming for, your timeline in weeks and how many resistance sessions you do a week. Recomposition, losing fat while building muscle, works best for beginners, people returning after a break and people with more body fat to lose (Barakat et al. 2020).
- Read the average daily deficit: the fat to lose × 7,700 kcal per kg, spread over your timeline. It is a deficit below your maintenance at the time, so recalculate maintenance with the TDEE Calculator every few weeks as your weight comes down.
- Check the target scale weight, the fat to lose and the weekly pace. The plan holds lean mass steady; any muscle you build on top takes body fat lower still. A pace above 1% of body weight a week is flagged: 0.5 to 1% a week best protects muscle (Helms, Aragon and Fitschen 2014).
- Hit the protein target (2.2 g per kg of lean mass, which lands near the 1.6 to 2.2 g per kg of body weight Morton et al. 2018 found supports muscle) and train each muscle with progressive overload at least 2 to 3 times a week.
- Track waist, lifts and progress photos, not just the scale: when fat loss and muscle gain overlap, the scale moves less than your body fat. If the timeline runs past a year, a dedicated cut followed by a lean gain is usually faster.
Questions people usually ask
Is body recomposition scientifically proven or just a fitness myth?
Body recomposition is scientifically supported, not a myth. Research by Barakat et al. (2020) in the Strength and Conditioning Journal, Longland et al. (2016) at McMaster University, and multiple studies reviewed by Helms, Aragon, and Fitschen (2014) confirm that simultaneous fat loss and muscle gain is physiologically possible under specific conditions. In the McMaster study, young men on 2.4 g/kg/day of protein gained 1.2 kg of lean mass while losing 4.8 kg of fat over 4 weeks, at a roughly 40% energy deficit with intense training six days a week. The key conditions are being in a mild caloric deficit (10-20% below maintenance), consuming adequate protein (1.6-2.2 g/kg/day), and training with progressive overload.
Who benefits most from body recomposition versus a traditional cut/bulk cycle?
Recomposition is most effective for three populations: beginners with less than 1 year of consistent resistance training, detrained individuals returning after a 3+ month break (who benefit from the muscle memory phenomenon documented by Staron et al.), and individuals with higher body fat percentages (above 20% for men, above 28% for women). These groups have heightened sensitivity to the training stimulus that allows nutrient partitioning toward muscle growth even during a caloric deficit. Intermediate and advanced lifters with lower body fat typically achieve better results through dedicated cut and bulk phases because their body has less energy reserve and less untapped muscle-building potential.
Why does the scale barely move during recomposition even when it is working?
During successful recomposition, muscle gain and fat loss offset each other on the scale: gaining 1 kg of muscle while losing 1 kg of fat leaves the scale where it was, while you look and perform differently (muscle is denser, so the same weight takes up less space). Research shows this equilibrium can last 4-8 weeks or longer. Better progress metrics during recomposition include waist circumference (should decrease 0.5-1 cm per month), strength on key lifts (should increase steadily), progress photos under consistent conditions, and body fat percentage measurements taken monthly.
How much protein do I need for body recomposition to work?
The Morton et al. (2018) meta-analysis in the British Journal of Sports Medicine established 1.6 g/kg/day as the threshold for maximizing muscle protein synthesis, with benefits plateauing around 2.2 g/kg/day. During recomposition, where you are in a caloric deficit, protein needs are at the higher end of this range because the deficit increases protein oxidation rates. Practically, this means a 80 kg person should consume 130-175 g of protein daily, distributed across 3-4 meals of 30-45 g each to optimize per-meal muscle protein synthesis signaling.
How long does body recomposition take compared to a traditional cut?
Recomposition is slower than a dedicated cut for fat loss but produces better body composition outcomes per unit of weight lost. A traditional cut at a 500-calorie deficit typically produces 0.5 kg of fat loss per week but also 0.1-0.2 kg of lean mass loss. Recomposition at a 150-300 calorie deficit produces approximately 0.2-0.3 kg of fat loss per week while potentially gaining 0.1-0.2 kg of lean mass. For someone targeting a 5% body fat reduction, a cut might take 10-14 weeks while recomposition might take 16-24 weeks, but the recomposition approach preserves or gains muscle in the process.
What happens if I am too experienced for recomposition to work?
If you have 3+ years of consistent resistance training and are already below 15% body fat (men) or 22% body fat (women), recomposition rates slow dramatically because your body has less untapped muscle-building potential and less energy reserve from body fat. At this point, a structured cut of 10-16 weeks at a 20-25% caloric deficit followed by a 4-6 week maintenance phase and then a lean bulk at 200-300 calories surplus typically produces better body composition changes in 6 months than 12 months of continuous recomposition. This planner does not model training age: if you are in this group, read its deficit as a cut that holds your muscle, not as a recomposition.
What training program works best for body recomposition?
A program emphasizing compound movements (squat, deadlift, bench press, overhead press, row) with progressive overload at 10-20 hard sets per muscle group per week is most effective. A meta-analysis by Schoenfeld, Ogborn and Krieger (2016) found that training each muscle group at least twice a week outperforms once-per-week training for hypertrophy. During recomposition, training intensity (proximity to failure) is more important than volume because the caloric deficit limits recovery capacity. Keep most working sets at RPE 7-8 (2-3 reps in reserve) to maintain training quality without exceeding recovery.
Can I do cardio during body recomposition?
Yes, but the type and amount matter. Low-to-moderate intensity cardio (Zone 2 heart rate, walking, cycling) supports fat oxidation and cardiovascular health without significantly impairing muscle recovery. High-intensity or high-volume cardio (more than 3-4 hours per week of running or HIIT) can interfere with muscle protein synthesis through the AMPK-mTOR interference pathway described in the concurrent training literature. Limit intense cardio to 2-3 sessions per week of 20-30 minutes and prioritize resistance training on days when both are scheduled.
Is this tool free and private to use?
Yes. AI Fit Hub tools are free, no-signup browser tools. All calculations run in your browser with no data transmission.
Does this replace medical or professional coaching guidance?
No. This tool provides evidence-based planning estimates for general fitness purposes. Individual results vary based on genetics, medical conditions, medications, sleep quality, stress levels, and other factors not captured by any calculator. Consult a qualified professional for personalized guidance.
The formula, worked through
- Formula Body Recomposition Formula
Body recomposition formula: target_weight = LBM / (1 − target_BF%/100). weekly_fat_loss = (current_weight − target_weight) / weeks.
- Formula Calorie Deficit Formula
The calorie deficit formula: daily deficit = TDEE minus intake, with 1 lb fat about 3,500 cal and 1 kg about 7,700 cal, plus a worked weekly-loss example.
- Formula Ideal Weight Formula (Devine 1974)
Ideal weight formula from the Devine 1974 equation: men 50 + 2.3 kg per inch over 60, women 45.5 + 2.3, plus Robinson, Miller and Hamwi variants.
Related calculators
- Planning Calorie Deficit Calculator
Estimate required daily calorie deficit for a target timeline and bodyweight change.
- Nutrition TDEE Calculator
Estimate your daily energy expenditure with Mifflin-St Jeor + activity factors.
- Nutrition Macro Calculator
Convert calorie targets into protein, carbs, and fat grams for your goal.
- Strength One-Rep Max Calculator
Estimate one-rep max with Epley, Brzycki, and Lombardi formulas.
Background on the Body Recomposition Planner
- Guide How to Do a Body Recomposition
How to body recomp: build muscle and lose fat at the same time. Macro targets, training structure, recovery rules, and the realistic timeline expectations.
- Examples Body Recomposition Examples
Explore real-world body recomposition examples, from busy professionals to athletes and new parents, revealing how to build muscle and lose fat.
- Checklist Body Recomposition Checklist
Plan body recomposition with this actionable checklist. Simultaneously build muscle and burn fat through precise nutrition, effective training.
- Checklist Bulking Phase Checklist
Plan a structured bulking phase with this actionable checklist. Learn to optimize nutrition, training, and recovery for effective hypertrophy.
Articles
- 13 min read Body Recomposition for Lifters: The Calorie Math
Body recomposition is real for specific populations under specific conditions. The four conditions, protein math scaled to LBM, 12-week example.
- 7 min read 20-Week Recomp: 84kg/24% to Target 18% Body Fat
Body recomp plan for an 84 kg male at 24% body fat, 20-week target 18%: 338 kcal/day deficit, 0.31 kg/week pace, 6.15 kg fat to lose, 140 g protein.
- 10 min read Body Composition: The Four Lenses
Body composition through four lenses: BMI, FFMI, measured body fat, and energy balance. What each metric answers, where it fails, and the deep dives.
By goal
Use it from code
The same calculation as a JavaScript module you can import. It runs where you import it, with no request, key or rate limit.
import { compute } from "https://aifithub.io/engines/body-recomposition-planner.js";Input and output contract, TypeScript types and the guide for agents.