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.

Scientific Claim

Acute starvation in healthy young adults is associated with a transient increase in resting metabolic rate, with a peak increase of 6% at 36 hours (from 4.60 to 4.88 kJ/min) followed by a return to baseline levels by 72 hours.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The study design (cohort study) can describe associations between starvation and physiological changes. The claim uses 'is associated with' which appropriately reflects the observational nature of the study.

Source Excerpt

“RMR rose from 4.60 kJ/min at 12 h to 4.88 kJ/min at 36 h and then fell again to a value of 4.72 kJ/min at 72 h (time effect P < 0.001, ANOVA). The 36 h value was significantly greater than that at 12 h (P < 0.001), but the 72 h value was not significantly different from the 12 h value (P = 0.06).”

Evidence from Studies

Supporting Evidence (1)

Why it supports

The study measured resting metabolic rate at multiple time points during starvation and found a statistically significant increase at 36 hours followed by a return to baseline levels by 72 hours.

Score

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

Cross-Sectional Study

Supported

Source Study

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

Score: 50

DOI: 10.1079/bjn19940150

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