Working out before eating breakfast burns about 3 grams more fat than working out after eating, because your body has to use stored fat for energy when you haven’t eaten.

Pro

Against

Evidence from Studies

Supporting (1)

Community contributions welcome

Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis

Systematic Review With Meta-Analysis

Human

2016 Oct

Contradicting (0)

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis

Score: 46

DOI: 10.1017/S0007114516003160

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