How Body Recomposition Planner works
Methodology for the Body Recomposition Planner: formulas, coefficients, data sources, assumptions, and known limitations.
Scope
Plans a time-bound recomposition: sets a small deficit, anchors protein to lean mass, and projects where body-fat percentage lands if the plan is executed.
Recomposition (simultaneous fat loss + muscle gain) is realistic for beginners, people returning from long breaks, and obese populations; it is slow for intermediate and advanced lifters.
Formula
Daily_calories = TDEE - small_deficit. Protein_g_per_day = protein_g_per_kg_lbm x LBM_kg. Target_bf_pct = current_bf_pct - projected_fat_loss_pct(duration, deficit).
Coefficients
| Parameter | Value | Note |
|---|---|---|
| Small deficit range | 200–400 kcal/day | |
| Protein target | 2.0–2.4 g/kg LBM/day | |
| Realistic muscle-gain ceiling | ~1% bodyweight / month (beginner), ~0.25% / month (intermediate) |
Data sources
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. — PMID 24864135. Foundational review for the protein-per-kg LBM targets used in the planner.
- Longland TM, Oikawa SY, Mitchell CJ, et al. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss. Am J Clin Nutr. 2016;103(3):738-746. — PMID 26817506. Simultaneous-LBM-gain-and-fat-loss RCT; underpins the recomposition feasibility claim.
- Barakat C, Pearson J, Escalante G, et al. Body recomposition: can trained individuals build muscle and lose fat at the same time? Strength Cond J. 2020;42(5):7-21. — Narrative review discussing the beginner/returner/obese populations where recomposition is most realistic.
Assumptions
- Training program includes 3+ heavy resistance sessions per week at or above the volume threshold required for hypertrophy.
- Sleep is adequate (>7 h/night) — sleep debt disables recomposition.
- Deficit is modest; large deficits convert the plan back into a standard cut.
Approximation range
Beginners and returners can expect 0.3–0.7% bodyfat reduction per week while adding measurable lean mass.
Intermediate and advanced lifters typically show either fat loss or lean-mass gain per phase, not both. The planner flags this and recommends a cut-then-gain structure.
Limitations
- DEXA or caliper body-fat estimates drift over time; treat week-to-week changes as noise.
- The planner does not model menstrual-cycle water fluctuation, which can mask 1–2 weeks of fat loss.
- Medication, sleep pathology, and stress can neutralize a well-written plan.
Reproducibility
Male, 85 kg, 18% bf, LBM 69.7 kg. TDEE 2800. Deficit 300. Daily kcal 2500. Protein 2.2 g/kg LBM = 153 g/day. 12-week projection at 300 kcal/day deficit: ~3.5 kg fat loss, target 13–14% bf.
Change log
- 2026-04-24: methodology page first published.
Related tools
- Calorie Deficit Calculator — Estimate required daily calorie deficit for a target timeline and bodyweight change.
- Hybrid Training Planner — Build a weekly schedule that balances running and lifting with interference warnings and recovery guidance.