What happens to your body when you skip food for 3 days?
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
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.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
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.
Publication
Journal
British Journal of Nutrition
Year
1994
Authors
J. Webber, I. Macdonald
Related Content
Claims (10)
Intermittent fasting without daily fasting maintains higher metabolic rate while still providing metabolic benefits.
Prolonged fasting (72 hours) impairs glucose tolerance, resulting in higher blood glucose and insulin responses to carbohydrate intake.
Specific intermittent fasting patterns (one 36-hour fast per week, two non-consecutive 24-hour fasts, or three separate 16-hour fasts) increase norepinephrine, fat oxidation, and glucose tolerance while avoiding metabolic downshift.
When people don't eat for 3 days, their heart rate goes up, increasing from about 62 to 69 beats per minute, with most of the increase happening within the first day and a half.
When people don't eat for 3 days, their body burns calories at a slightly higher rate for about a day and a half, then returns to normal levels.