What caloric surplus to gain muscle without fat?

It's physiologically impossible to gain muscle without any fat (except in special cases: beginners, recomposition at maintenance). But you can get close with a lean bulk: 200–300 kcal/day surplus, protein at 2.0–2.2 g/kg, strength training 4–5×/week, sleep ≥ 8 h. Under these conditions, the muscle-to-fat ratio reaches 50–60% muscle for an intermediate lifter, 60–70% for a beginner.

How much protein during a surplus?

1.8 to 2.2 g per kg of body weight is enough. Beyond 2.5 g/kg, studies (Schoenfeld 2018) show no additional benefit. For a 75 kg lifter: 135–165 g/day, spread across 4–5 servings.

How many kg of muscle can you gain per month?

The scientific literature converges on these estimates: beginner 0.5–1 kg of muscle/month during the first months, intermediate 0.2–0.4 kg/month, advanced 0.1–0.2 kg/month. Anything above that is water, glycogen or fat.

What's the difference between BMR and TDEE?

BMR is the minimum energy spent at complete rest. TDEE adds all of your daily physical activities on top. The surplus is applied to TDEE to calculate your muscle-gain calorie target.

How long should a bulk last?

For a beginner, 4–6 consecutive months. For an intermediate lifter, 8–16 week cycles followed by 4–6 week mini-cuts work better long-term. For an advanced lifter, short 6–10 week cycles with more frequent mini-cuts.

Lean bulk vs dirty bulk: which one to choose?

Lean bulk (moderate surplus of 10–20%) for almost all lifters. Recent meta-analyses (Iraki, Aragon, Schoenfeld 2019) confirm it produces better results at 12 months. Dirty bulk only remains relevant for extreme ectomorphs.

When should you end a bulk phase?

When your body fat exceeds 18% (men) or 25% (women), or if your waist circumference grows faster than your arm/thigh measurements. Switch to a 4–6 week mini-cut before starting a new bulk.

What if I'm not gaining weight despite the surplus?

Three causes: (1) underestimating TDEE — your expenditure is higher than expected, add 200 kcal/day, (2) overestimating intake — weigh your food for a week to check, (3) unconsciously high NEAT. Recalibrate over 14 days and adjust by 250 kcal if the plateau persists.

Personne courant sur une colline au coucher du soleil

TrainingSourced · Mifflin-St Jeor formula

Calorie surplus calculator

Get your daily calorie target and macros in seconds for effective muscle gain, tailored to your level.

By Adrien Grusse · Micron 創業者

Published 2026年4月27日 · Updated 2026年4月28日

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Age

yrs

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Weight

Activity level

Surplus type

The recommended approach for most lifters: clean muscle gain with an optimized muscle-to-fat ratio.

Strength training experience

Enter your age, height and weight

to get your muscle-gain calorie target

最も充実した栄養アプリ

カロリーを写真から記録。

食事を撮るだけで、カロリー・マクロ・30種類以上の微量栄養素を即座に計算します。

4.8 · 2,300件以上の評価

How does the calculation work?

Step 01

Basal Metabolic Rate (BMR)

The Mifflin-St Jeor formula, considered the most accurate by current scientific literature. It calculates your minimum calorie needs at rest from your sex, age, height and weight.

Step 02

Total Daily Energy Expenditure (TDEE)

We multiply your BMR by a physical activity coefficient (1.2 to 1.9) to estimate your actual daily calorie expenditure. This is your maintenance threshold.

Step 03

Calibrated surplus + macros

We apply a surplus of +10%, +15% or +20% depending on the mode you chose. Macros are calibrated for muscle gain: protein at 2.0 g/kg, fat at 28%, carbs as the remainder.

What is a caloric surplus?

A caloric surplus is the opposite of a deficit: you eat more calories than your body burns. Combined with resistance training and adequate protein intake, this surplus provides the energy needed for muscle protein synthesis — the physiological foundation of any muscle-gain phase.

The key isn't to eat "a lot," but to eat "just enough" to maximize muscle gain while limiting fat gain. A moderate surplus of 200–400 kcal/day is enough for most lifters.

For a deeper dive — lean bulk vs dirty bulk, realistic muscle-to-fat ratios per training level, when to stop, considerations for women, mistakes to avoid and 12 common questions: read the complete guide on caloric surplus →

What muscle-to-fat ratio can you expect?

Whatever the size of your surplus, your body can only build 0.2 to 0.5 kg of muscle per month on average (Helms et al., 2014). Any extra calories not used for muscle protein synthesis are stored as fat. That's why calibrating matters.

4 tips to optimize your muscle gain

Aim for 2.0 g/kg of protein

Spread across 4 servings of 30–40 g, 3–4 hours apart. Beyond 2.2 g/kg, studies show no additional benefit.

Progress in the gym

A surplus only makes sense paired with progressive overload. Your loads and/or volume must increase over 8–12 weeks, otherwise the surplus turns into fat.

Sleep 7–9 hours

Muscle protein synthesis peaks during sleep. Truncated sleep (< 6 h) reduces protein synthesis by 18% (Dattilo et al., 2011).

Weigh yourself weekly

Always under the same conditions (fasted, in the morning). If you gain more than 0.7 kg/week, cut the surplus by 100–150 kcal. If you stall for 2 weeks, add 100 kcal.

Frequently asked questions about caloric surplus

科学的な出典

この記事は、以下に挙げる査読済みの研究・刊行物7件にもとづいています。各リンクは一次情報（PubMed、NIH、政府機関、学術誌）に直接つながります。

[1]Helms ER, Aragon AA, Fitschen PJ (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition. 出典を見る ↗PMID : 24864135
[2]Schoenfeld BJ, Aragon AA (2018). How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Journal of the International Society of Sports Nutrition. 出典を見る ↗PMID : 29497353
[3]Iraki J, Fitschen P, Espinar S, Helms E (2019). Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 出典を見る ↗PMID : 31247944
[4]Dattilo M, Antunes HK, Medeiros A, et al. (2011). Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis. Medical Hypotheses. 出典を見る ↗PMID : 21550729
[5]Phillips SM, Van Loon LJ (2011). Dietary protein for athletes: from requirements to optimum adaptation. Journal of Sports Sciences. 出典を見る ↗PMID : 22150425
[6]Morton RW, Murphy KT, McKellar SR, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. 出典を見る ↗PMID : 28698222
[7]Garthe I, Raastad T, Refsnes PE, et al. (2013). Effect of nutritional intervention on body composition and performance in elite athletes. European Journal of Sport Science. 出典を見る ↗PMID : 23574396

About the author

Adrien Grusse

Micron 創業者

アドリアン・グリュスは、15万人以上のユーザーが日々の微量栄養素を記録するアプリ「Micron」の創業者です。Micron以前は、Finary（Y Combinator）のグロースチームに在籍していました。アドリアンは有資格の管理栄養士ではありません — ここでの役割は、科学的な文献を正確に、わかりやすく伝えることです。すべての記事は査読済みの文献（PubMed、Cochrane、近年のメタアナリシス）を出典として明示しており、検証可能な根拠のない主張は掲載していません。個別の医学的なフォローアップについては、医療専門家にご相談ください。

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