ScienceContemporaryglobalhigh confidence

Short-term fasting may temporarily increase metabolic rate by increasing the release of norepinephrine, a fat-burning hormone.

Notes on verification

Confirmed by peer-reviewed studies (Zauner et al. 2000, AJCN; adipose norepinephrine spillover studies) showing short-term fasting raises norepinephrine and metabolic rate, with effect reversing after a few days.

Sources