How much weight is safe to lose per week?

What is a sustainable pace?

A practical rule: about 0.5–1% of your body weight per week. For an 80 kg person, that's 0.4–0.8 kg a week. If you're just starting out and your weight is high, you can lean toward the upper end; as you approach your goal, the lower end becomes more realistic.

The number may look small, but combined with consistency it adds up: half a kilo a week is roughly six kilos in three months.

How is a calorie deficit calculated?

Roughly, 1 kg of body fat is equal to about 7,700 kcal. So a deficit of 500 kcal a day means about 3,500 kcal a week and about 0.45 kg.

This calculation is a starting estimate. As you lose weight your body gets smaller, you burn less, and the same deficit gives slower results over time. That's why it's more accurate to track progress with your average weight than with any single number.

Worked example

Why shouldn't you lose weight too fast?

• Muscle loss increases. In a study of elite athletes, the group losing about 0.7% of body weight per week kept their muscle mass and improved strength, while the group losing 1.4% could not.
• It gets harder to sustain. A very harsh deficit means hunger, fatigue and food occupying your mind. The result is usually quitting and regaining.
• The risk of nutrient shortfalls rises. On a very low calorie intake, meeting vitamin and mineral needs becomes difficult.

Safe limits

• Avoid very low calorie diets without professional supervision. Guidelines generally suggest a starting range of 1,200–1,500 kcal for women and 1,500–1,800 kcal for men, with a deficit of 500–750 kcal.
• Don't set your calorie target below your basal metabolic rate.
• Keep protein high (about 1.2–1.6 g/kg) and do resistance exercise a few days a week; it reduces muscle loss.
• If your average weight hasn't moved for three weeks, adjust the target by 100–200 kcal; don't change it every day.

When should you see a professional?

If you are pregnant or breastfeeding, have a chronic condition such as diabetes, kidney or thyroid disease, take regular medication, are under 18, or have had an eating disorder in the past, build your weight loss plan with a doctor or dietitian.

Sources

1. Hall KD et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826–837.
2. Garthe I et al. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011;21(2):97–104.
3. Jensen MD et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults. Circulation. 2014;129(25 Suppl 2):S102–S138.
4. World Health Organization. Healthy diet fact sheet, 2020.

This content is for information only and is not medical advice. Last updated: October 12, 2026.