Quick Answer
7,700 calories

One kilogram (1 kg) of body fat contains approximately 7,700 calories

The Science Behind the Number

Body fat isn't pure fat. It's composed of approximately 87% lipids (fat), plus water, protein, and other tissues. While pure fat contains about 9 calories per gram (or 9,000 per kilogram), body fat tissue contains roughly 7,700 calories per kilogram when accounting for its actual composition.

What This Means for Weight Loss

To lose 1 kg of body fat, you need to create a calorie deficit of approximately 7,700 calories. This deficit can be achieved through:

  • Reducing your calorie intake
  • Increasing physical activity
  • A combination of both (most effective)

Practical Examples

Daily 500 cal deficit

Lose 1 kg in ~15 days

7,700 ÷ 500 = 15.4 days

Daily 1,000 cal deficit

Lose 1 kg in ~8 days

7,700 ÷ 1,000 = 7.7 days

Daily 300 cal deficit

Lose 1 kg in ~26 days

7,700 ÷ 300 = 25.7 days

Important Considerations

  • Not all weight loss is fat: Initial weight loss often includes water weight
  • Sustainable deficit: A 500-1,000 calorie daily deficit is generally safe and sustainable
  • Minimum intake: Don't go below 1,200 calories/day (women) or 1,500 calories/day (men) without medical supervision
  • Individual variation: Metabolic rate, activity level, and body composition affect results

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