The claimEvidence B · meta-analysis
Fasted cardio burns more fat
The evidence
It confuses proportion with absolute amount. Fat loss is set by the 24-hour energy balance, not by which fuel you burn during the session.
Why the claim spreads
It rests on a real observation: fasted training really does raise the proportion of energy coming from fat. Reading 'higher proportion' as 'more fat lost' is one short step, and almost nobody in a gym stops you taking it.