Numbers guideSourced · Hall 2011 · Helms 2014

How many calories to lose weight?

Quick estimate across 3 paces (slow, moderate, fast). For a full personalized calculation (Mifflin-St Jeor + macros), use the dedicated calculator.

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By Adrien Grusse

Published on 2026年4月29日 · Updated on 2026年4月29日

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Optional — to estimate duration. Leave empty if you only want kcal/day.

Activity level

TDEE estimate based on FAO/WHO multipliers. For exact figures (Mifflin-St Jeor + macros), see the calculator below.

Target

2,040kcal/d

Moderate · Recommended

Duration

23wks

−0.46 kg/wks

Other paces

Slow

2,168

31 wks

Fast

1,913

19 wks

Mifflin-St Jeor BMR + activity-based TDEE + macros (protein, carbs, fat) in 30 seconds.

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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。

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4.8 · 2,300件以上の評価

The scientific formula: 7,700 kcal = 1 kg of fat

The principle is simple: 1 kg of adipose tissue contains ~87% pure lipids (the remaining 13% is water, protein and cellular structure). Since 1 g of lipid = 9 kcal of energy, we get:

1 kg of fat = ~7,700 kcal

(1,000 g × 87% × 9 kcal/g ≈ 7,830 kcal, rounded to 7,700 kcal in clinical practice)

This rule (Wishnofsky 1958) is still useful as a first approximation. Modern models (Hall 2011) show that reality is more dynamic — metabolic adaptation lowers TDEE during a deficit, slowing weight loss. But for setting a daily target, the 7,700 kcal/kg rule works very well over 8 to 12 weeks.

How many calories by profile

Concrete examples for the most common profiles. The deficit shown is moderate (-20%, the recommended equivalent in most cases).

ProfileTDEETargetPace
Male 60 kg, sedentary1 8001 440−0,33 kg/wks
Male 80 kg, sedentary2 4001 920−0,44 kg/wks
Male 80 kg, sport 3-5×/week3 2002 560−0,58 kg/wks
Female 60 kg, sedentary1 6201 296−0,29 kg/wks
Female 65 kg, sedentary1 7551 404−0,32 kg/wks
Female 70 kg, sport 3-5×/week2 5902 072−0,47 kg/wks

TDEE = Total Daily Energy Expenditure. Estimates based on FAO/WHO multipliers; for exact figures (Mifflin-St Jeor), use the calculator.

How many calories to lose 1, 5, 10, 20 kg?

For a given daily deficit, here is the theoretical duration to reach a weight loss goal. Note: for large losses (10-20 kg), add +20-30% duration due to metabolic adaptation.

GoalCumulative deficitSlow paceModerate paceFast pace
1 kg7,700 kcal~4 wks~2 wks~1.5 wks
2 kg15,400 kcal~9 wks~4 wks~3 wks
5 kg38,500 kcal~22 wks~11 wks~7 wks
10 kg77,000 kcal~44 wks~22 wks~15 wks
20 kg154,000 kcal~88 wks~44 wks~29 wks

Paces calculated on an average deficit of -300 kcal/day (slow), -500 kcal/day (moderate), -750 kcal/day (fast). For goals > 10 kg, split into 8-10 week blocks + 2-week diet breaks at TDEE (Byrne 2018).

5 traps that derail 80% of diets

Knowing your calorie target is not enough — here are the recurring mistakes that sabotage results, identified by weight-loss meta-analyses.

01

Underestimating intake

Lichtman (1992, NEJM) showed a -47% gap between declared and actual intake in overweight individuals. Solution: weigh all foods over 7 days to calibrate.

02

Not recalculating TDEE after losing 5 kg

Your expenditure drops with your weight (~25 kcal/kg lost) AND with metabolic adaptation. At -10 kg, your new kcal target is ~250 kcal below the previous one.

03

Going below 1,200 kcal (women) or 1,500 (men)

Risks: deficiencies (iron, B12), muscle loss, persistent metabolic slowdown. If the calculation falls below, increase output rather than cutting intake.

04

Neglecting protein

Without 1.8-2.2 g/kg of protein, you lose 30-40% muscle mass instead of 10-15%. The scale result is misleading — you lose muscle, not fat.

05

Bouncing back too fast after reaching the goal

Returning to your old maintenance = +3-5 kg in 2 weeks (60% as fat). Solution: reverse diet, +100 kcal/week over 4-6 weeks to stabilize.

Frequently asked questions about calories for weight loss

Scientific sources

The figures and recommendations on this page are based on 6 peer-reviewed studies listed below. All links point to the original source (PubMed, scientific journals).

  1. [1]Hall KD, Sacks G, Chandramohan D, et al. (2011). Quantification of the effect of energy imbalance on bodyweight. The Lancet. View source ↗PMID : 21872751
  2. [2]Hall KD (2008). What is the required energy deficit per unit weight loss?. International Journal of Obesity. View source ↗PMID : 17848938
  3. [3]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. View source ↗PMID : 24864135
  4. [4]Lichtman SW, Pisarska K, Berman ER, et al. (1992). Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. New England Journal of Medicine. View source ↗PMID : 1454084
  5. [5]Byrne NM, Sainsbury A, King NA, et al. (2018). Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study. International Journal of Obesity. View source ↗PMID : 28925405
  6. [6]Heymsfield SB, Thomas D, Bosy-Westphal A, et al. (2012). Evolving concepts on adjusting human resting energy expenditure measurements for differences in body size. Obesity Reviews. View source ↗PMID : 22862434
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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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