Research
Macro partitioning
Increasing fat availability before exercise (via high-fat diet or fat infusion) reduces carbohydrate utilization but does not improve exercise performance.
Do not rely on high-fat diets or fat infusions to improve your endurance performance. While it changes how your body burns fuel (less carbs, more fat), it does not make you faster and may even make you slower compared to a high-carb diet.
GoodRefutesHIGH confidence
Interventions to increase fat availability before exercise have been shown to reduce carbohydrate utilization during exercise, but do not appear to have ergogenic benefits.
Why this rating
Consistent findings across multiple studies (Starling, Burke, Carey, Hawley) showing no performance benefit.
Source
Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance
Mark Hargreaves et al. · Journal of Sports Sciences · 2003
narrative_reviewCited 178×
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