To lose 1 kg a week you need a daily deficit of about 1,100 kcal (7,700 kcal per kg ÷ 7 days). If your maintenance calories are 2,500, that means eating about 1,400 kcal a day. For many women with maintenance under 2,300 kcal, 1 kg a week would mean eating fewer than 1,200 kcal, so 0.5 kg a week is more suitable.
Calories to lose 1 kg a week
Is 1 kg a week right for you?
| Maintenance calories | For 1 kg/week | For 0.5 kg/week |
|---|---|---|
| 1,800 kcal | 700 kcal – too low | 1,250 kcal |
| 2,000 kcal | 900 kcal – too low | 1,450 kcal |
| 2,400 kcal | 1,300 kcal | 1,850 kcal |
| 2,800 kcal | 1,700 kcal | 2,250 kcal |
| 3,200 kcal | 2,100 kcal | 2,650 kcal |
1 kg a week is most realistic if you have a higher starting weight, are male, or are very active. For everyone else, 0.5 kg a week is safer and easier to keep up.
Making a 1,100 kcal deficit work
- Combine food and activity: e.g. 800 kcal less food + 300 kcal from a daily 45–60 minute walk.
- Prioritise protein (about 1.2–1.6 g per kg of body weight is often used) to protect muscle.
- Fill up with vegetables and high-fibre foods.
- Cut back alcohol and sugary drinks first – easy calories to lose.
- Review after 3 weeks; slow down if you feel unwell.
Frequently asked questions
How many calories should I eat to lose 1 kg a week?
About 1,100 kcal less than your maintenance calories each day.
Is losing 1 kg a week safe?
The NHS says 0.5 to 1 kg a week is safe for most adults, so 1 kg is the upper end.
How many calories is 1 kg of fat?
Roughly 7,700 kcal.
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Medical disclaimer: this tool gives an estimate for adults and is not a diagnosis or medical advice. bmicalculatornhs.net is independent and not affiliated with the NHS. Speak to your GP, pharmacist or another qualified health professional about your own health. Full disclaimer.