How many calories to lose 1kg per week? Losing 1 kg of fat per week is an ambitious but achievable target for some people — and too aggressive for others. Whether it is right for you depends on your current weight, muscle mass, and how you create the deficit. Here is the precise calculation and the honest limits.
The Maths Behind Losing 1 kg Per Week
One kilogram of body fat contains approximately 7,700 kcal of stored energy. To lose 1 kg of fat in 7 days requires a total weekly deficit of 7,700 kcal — or 1,100 kcal per day.
This is a very large deficit. For context:
| Body weight | Typical TDEE (moderate activity) | 1 kg/week target intake | Feasible? |
|---|---|---|---|
| 60 kg woman | ~1,900 kcal | ~800 kcal | ❌ Too low — muscle loss risk |
| 75 kg woman | ~2,100 kcal | ~1,000 kcal | ⚠️ Borderline — supervision advised |
| 90 kg man | ~2,800 kcal | ~1,700 kcal | ✅ Feasible with resistance training |
| 110 kg man | ~3,200 kcal | ~2,100 kcal | ✅ Achievable and relatively safe |
Who Can Safely Lose 1 kg Per Week?
Generally, people with a BMI above 30 (and therefore a higher TDEE) can create a 1,100 kcal daily deficit without going below safe calorie minimums. People with lower body weights should target 0.5–0.7 kg per week instead — which requires a 550–750 kcal daily deficit.
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Calculate My Calories →A Better Approach: Split the Deficit Between Food and Exercise
Rather than creating a 1,100 kcal deficit purely through eating less, a safer and more sustainable approach is:
- Eat 600–700 kcal below TDEE through food choices
- Burn 300–400 additional kcal through exercise (daily brisk walks, resistance training)
- Total deficit: ~1,000 kcal/day — approaching 1 kg/week without extreme food restriction
This split approach preserves muscle mass better, maintains higher metabolic rate, and is more psychologically sustainable.
Why 0.5 kg Per Week May Be Better
Research comparing aggressive (1 kg/week) vs moderate (0.5 kg/week) fat loss rates consistently shows:
- Moderate deficit groups lose more fat and less muscle relative to total weight lost
- Moderate deficit groups maintain higher metabolic rates throughout the diet
- Moderate deficit groups have higher adherence rates at 6 and 12 months
- Long-term outcomes (weight at 2 years) are better with moderate deficits
Frequently Asked Questions
Is it safe to lose 1 kg per week?
Why do I lose more than 1 kg in the first week?
Find your exact daily calorie needs — personalised and free.
Calculate My Calories →Sources & References
- Hall KD. “What is the required energy deficit per unit weight loss?” International Journal of Obesity, 2008;32(3):573–576. Supports the ~7,700 kcal per kg (3,500 kcal/lb) energy figure and explains why the required deficit varies with body fat and sex. PubMed: 17848938
- National Heart, Lung, and Blood Institute. “Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults” (NIH; NCBI Bookshelf NBK2003). Supports the recommended ~0.45–0.9 kg (1–2 lb) per week rate, the 500–1,000 kcal/day deficit, and low-calorie-diet minimums. NIH/NHLBI Clinical Guidelines
- MedlinePlus (U.S. National Library of Medicine). “Diet myths and facts.” Supports evidence-based guidance favouring moderate, sustainable rates of weight loss. NIH/MedlinePlus: Diet myths and facts
Last reviewed against the above sources: June 2026.