Taking protein supplements for several weeks might help athletes perform better than taking them just once, but we’re not totally sure because the studies didn’t control for total calorie intake.

Taking about an extra gram of protein per pound of body weight every day — mostly from supplements — might help athletes perform their best, but it's hard to be sure because most studies don’t account for total calories.

Protein supplements might give athletes a small boost in endurance, especially when taken with carbs—but it could just be because they're eating more calories overall.

Athletes taking protein might get stronger, but it could just be because they're eating more total calories — not because of the protein itself.

If you eat protein and carbs right after working out, you might recover faster, feel less tired, and refill your energy stores better than if you wait more than 2 hours.

If young guys lift weights hard and do intense workouts while eating less for a month, chugging 2.4 grams of protein per pound of muscle each day helps them gain more muscle and lose more fat than eating half that much protein.