If elite male cyclists eat a super high-fat diet for 6 days before carb-loading for a day, they’ll feel just as fast over a long 100-km ride — but they’ll have less power for short, intense sprints compared to when they eat a high-carb diet first.

If elite male cyclists eat a super high-fat diet for six days and then carb-load for one day, they’ll perform worse in sprints—even though they don’t feel more tired, their heart rate doesn’t change, and their muscles fire the same way.

If a male cyclist eats a super high-fat diet for 6 days and then loads up on carbs for 1 day, it won’t slow them down in a 100-km race compared to eating lots of carbs all along.

If male cyclists eat a super high-fat diet for six days, their body's 'fight or flight' system might get a bit more active — and that change doesn’t go away right after they start eating carbs again.

Whether you eat carbs, protein, or nothing before a hard cycling workout with short bursts of maximum effort, your power output stays the same — your body can still push hard regardless of what you ate beforehand.

For endurance athletes, switching to a high-fat diet for six days and then loading up on carbs doesn’t seem to boost performance in a one-hour cycling test compared to sticking with a high-carb diet.