If young guys do really intense cycling and don't eat carbs afterward, they lose about half a kilo of lean weight in a day—mostly from lost muscle fuel and water. But if they eat carbs, their lean...

After a really tough bike ride, young guys can lose about half a kilo of 'lean mass' the next day if they don’t eat enough carbs to refuel — but it’s not muscle loss, it’s mostly water stuck to stored fuel in the body.

If untrained guys eat a high-fat diet for 7 weeks, their muscles use less stored sugar during medium-intensity exercise compared to eating a high-carb diet — it’s like saving their fuel — but their legs still take up the same amount of glucose from the blood.

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.

If elite male cyclists don't eat carbs after a hard workout that drains their energy stores, their muscle and liver won't refill those energy reserves for at least 12 hours.

If Japanese male endurance athletes don't eat enough carbs after tough exercise—like less than 7 grams per kilo of body weight—their muscles refill energy slower in the first half-day, especially between 4 to 12 hours after.