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 happens most readily in three groups: beginners, people returning after a layoff (retained muscle nuclei make regaining size faster), and people with more body fat to lose. Lean, advanced lifters gain muscle slowly whatever they do, so many get further with separate cut and bulk phases, although slow recomposition is possible with high protein and hard training.
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?
It is slower for fat loss, because the deficit is smaller. Fat loss follows the deficit at roughly 7,700 kcal per kg, so a 250 kcal daily deficit is about 0.2 kg of fat a week against about 0.45 kg at 500 kcal. The trade is that a small deficit with hard training and high protein makes it easier to keep or add muscle. Expect months, not weeks.
What happens if I am too experienced for recomposition to work?
If you have years of training behind you and are already lean, recomposition slows to a crawl: there is little untapped muscle to add and little fat to fund it. Many lifters in that position get further with a structured cut followed by a lean bulk. 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. When weekly volume is equal, training a muscle once, twice or three times a week builds similar muscle (Schoenfeld 2019), so split the sets however lets you keep their quality high. 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.
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- 7 min read 20-Week Recomp: 84kg/24% to Target 18% Body Fat
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By goal
Use it from an agent or code
Any agent can run this calculator by URL: put the inputs in the query string and get JSON back, with the inputs that used defaults and a line to cite (add format=md for markdown). MCP clients reach it through https://aifithub.io/mcp.
In code, import the same module; it runs where you import it, with no request or key.
import { compute } from "https://aifithub.io/engines/body-recomposition-planner.js";Input and output contract, TypeScript types and the guide for agents.