BODY RECOMPOSITION • LEAN BULK SURPLUS • CALORIE CYCLING • MACROS TO CALORIES
Cycle your calories and carbohydrates between lifting days (+10% surplus) and rest days (−15% deficit) for simultaneous fat loss and muscle gain, or dial in a controlled +200 to +300 kcal Lean Bulk surplus anchored to your Lean Body Mass.
VERIFIED WORKED EXAMPLES & SCIENTIFIC BENCHMARKS
See how clinical equations and anthropometric formulas compute exact results across realistic scenarios:
Partitioning calories around resistance training fuels muscle protein synthesis on workout days while mobilizing fat stores on rest days.
A controlled ~240 kcal/day average surplus supports ~0.2–0.25 kg/week of lean weight gain without unnecessary adipose spillover.
Converting macros to calories multiplies protein (612 kcal) and carbs (1,280 kcal) by 4 and fat (630 kcal) by 9.
PEER-REVIEWED EQUATIONS & METHODOLOGY
Compare Katch-McArdle training-day and rest-day calorie cycling for body recomposition against controlled lean bulking (+200–300 kcal), standard hypertrophy bulks, and Atwater 4-4-9 macro-to-calorie conversions:
| Benchmark / Query Parameter | Clinical Target / Formula Output | Practical Application & Physiological Notes |
|---|---|---|
| Body Recomposition (+10% Lift / −15% Rest) | 2.2 – 2.5 g/kg LBM Protein | Best for skinny-fat lifters, returning athletes, or women/men at 14–22% (male) / 21–30% (female) body fat. |
| Lean Bulk (+200 to +300 kcal Surplus) | 0.25% to 0.5% Body Weight Gain / Month | Maximizes the muscle-to-fat gain ratio for intermediate and advanced lifters already lean (<14% M / <22% F). |
| Standard Hypertrophy Bulk (+400 to +500 kcal) | 0.5% to 1.0% Body Weight Gain / Month | Suited for underweight novices ('hardgainers') in their first 12 months of barbell training. |
| Macro-to-Calorie Conversion (4-4-9 Rule) | Protein×4 + Carbs×4 + Fat×9 (+ Alcohol×7) | Instantly converts any gram macro split into exact kilocalories and percentage energy distribution. |
AUTHORITATIVE SOURCES & CLINICAL REFERENCES
Configuring a body recomposition or lean bulking protocol requires matching energy availability to your weekly resistance-training schedule:
Choosing between recomposition and bulking depends on your current body fat percentage and training experience:
Peer-reviewed sports science (Barakat et al., 2020; Iraki et al., 2019) demonstrates that skeletal muscle hypertrophy and adipose lipolysis occur in separate tissue compartments: (verified against USDA FoodData Central and FDA 21 CFR 101.9 / 101.36 Reference Standards):
| Scenario / Task | Common Mistake (Before) | Verified Calculation (After) | Scientific / Culinary Reason |
|---|---|---|---|
| Running a +800 kcal 'Dirty Bulk' at 20% Body Fat | Gaining 2 lbs/week (~75% fat mass, 25% lean tissue) | Body Recomp (+10% Lift / −15% Rest) until 12%–14% BF | Starting a large caloric surplus above 18%–20% male body fat reduces insulin sensitivity and accelerates adipose gain. |
| Cutting Protein on Rest Days During Recomp | Dropping protein from 170g on lift days to 100g on rest days | Keep Protein Constant (2.2–2.5 g/kg LBM) All 7 Days | Muscle protein synthesis remains elevated for 24–48 hours post-workout; cycle carbohydrates and calories, never protein. |
| Converting Macros to Calories with 4 kcal/g for Fat | Treating 70g fat as 280 kcal instead of 630 kcal | Atwater 4-4-9: (P×4) + (C×4) + (F×9) | Dietary lipids supply 9 kcal per gram—more than double the energy density of protein or carbohydrates. |
BODY RECOMPOSITION • LEAN BULK SURPLUS • CALORIE CYCLING • MACROS TO CALORIES
Body recomposition (losing fat and building muscle simultaneously) uses calorie cycling around your Katch-McArdle TDEE: on resistance training days you eat a 10% caloric surplus with higher carbohydrates to drive muscle protein synthesis, and on rest days you eat a 15% caloric deficit with lower carbs while keeping protein high (2.2–2.4 g/kg LBM).
A lean bulk adds a modest, controlled surplus of +200 to +300 calories above TDEE (~8%–12% surplus), matching the biological rate limit of human skeletal muscle synthesis (~0.25 to 0.5 lbs of contractile tissue per week). Eating +1,000 kcal ('dirty bulking') does not accelerate muscle growth—it only stores excess triglycerides.
Multiply grams of protein by 4 kcal/g, grams of carbohydrates by 4 kcal/g, and grams of fat by 9 kcal/g, then add the three values together. If alcohol is included, multiply grams of alcohol by 7 kcal/g.
Yes. Because our engine uses the Katch-McArdle Lean Body Mass formula rather than generic scale weight, female lifters get accurate training-day and rest-day calorie targets tailored to their exact lean muscle mass.
Compute Katch-McArdle BMR, training-day and rest-day calorie cycling for body recomposition, controlled lean bulk surpluses, and Atwater macro-to-calorie conversions.
Adjust your measurements or load a preset scenario at the top of the page to export your personalized breakdown.
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