Eating carbs before a workout when you haven't eaten all night might make you feel like you can lift more—but it's probably because you feel less hungry or think you're getting energy, not because your muscles actually have more fuel.

Feeling like you’ve eaten something before a workout — even if it’s just a fake meal with no calories — can make you lift more, not because of carbs, but because you feel less hungry or more ready.

Eating carbs after a super-hard workout helps you perform better — but only if you were starving before. If you ate the same number of calories from protein or fat, carbs don’t help any more.

If you eat before working out, your blood sugar and insulin levels spike more during exercise than if you work out on an empty stomach.

After a tough leg workout, drinking a sugary sports drink instead of water helps your muscles refill their energy stores faster, so you recover better after six hours.