Nutrition & supplements
How long will it take to lose weight at your calorie deficit?
Days and weeks to reach your weight goal from daily calorie deficit — 7,700 kcal per kg of fat.
Quick answer
Fat loss obeys energy balance: about **7,700 kcal per kilogram** of fat tissue. Lose **5 kg** with a **500 kcal/day deficit** → **5 × 7,700 ÷ 500 ≈ 77 days** (~11 weeks) — not "5 weeks" unless the deficit is much larger.
Days to goal
77 days
- Weeks (approx.)
- ~11
- Total deficit needed
- 38,500 kcal
Rule of thumb: 1 kg of fat ≈ 7,700 kcal. A 500 kcal/day deficit loses about 0.45 kg/week — sustainable for many adults. Faster deficits need medical supervision; muscle loss rises below ~1,200 kcal intake for women / 1,500 for men.
How it works
A 500 kcal deficit is the classic sustainable target (~0.45 kg/week). Faster cuts lose more muscle and rebound harder; pair the timeline with adequate protein (1.6–2.2 g/kg) and resistance training. Track on a smart scale weekly, not daily — water masks real fat loss.
Frequently asked questions
How long to lose 10 kg at 500 kcal deficit?+
10 × 7,700 ÷ 500 = 154 days — about 22 weeks. Plateaus and logging errors stretch real timelines; treat this as math, not a guarantee.
Is a 1,000 kcal deficit safe?+
Only for very heavy individuals under supervision. For most adults it risks muscle loss, binge cycles and micronutrient gaps. 300–500 kcal is the usual sustainable range.
Why am I not losing weight on 500 kcal deficit?+
Common causes: underestimated eating, overestimated burn, water retention from new training, or metabolic adaptation. Re-check intake for two weeks with a scale; adjust deficit modestly, not drastically.
Does the 7,700 kcal rule include water weight?+
It approximates fat tissue only. Early diet weeks drop glycogen and water fast — the scale moves quicker than 7,700 kcal/kg predicts; fat loss rate stabilizes after 2–4 weeks.
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