What happens to your body when you skip food for 3 days?

Original Title

The cardiovascular, metabolic and hormonal changes accompanying acute starvation in men and women

Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms

Summary

When healthy people don't eat for 3 days, their bodies make changes to use fat for energy instead of sugar.

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Surprising Findings

Metabolic rate increases temporarily during starvation

Common belief is that metabolism slows during fasting to conserve energy, but this study shows a 6% increase at 36 hours — which contradicts the typical 'starvation mode' narrative.

Practical Takeaways

If you're doing intermittent fasting, know that your metabolism might temporarily increase for about 1.5 days before stabilizing — but don't expect continuous calorie burn boost.

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Publication

Journal

British Journal of Nutrition

Year

1994

Authors

J. Webber, I. Macdonald

Open Access
68 citations