If young guys who don't usually lift weights eat about 1.6 grams of protein per kilo of body weight every day—whether from plant-based foods and soy protein or from regular mixed diets with whey—they...

If young adults who aren't used to working out eat a bit more protein—especially from whey or soy—and lift weights 3 times a week for 3 months, they’ll likely gain more muscle and get stronger, even if they weren’t eating enough protein to start with.

If young guys who don’t work out much eat a plant-based or meat-based diet with the same amount of protein and lift weights for 12 weeks, they’ll gain about the same amount of leg muscle and strength.

If female college athletes who lift weights drink a protein shake with 24 grams of protein before and after workouts for eight weeks, they’ll get stronger in their upper body — especially if they use whey protein instead of casein.

Young men who lift weights for muscle growth and eat more than 2.0 grams of protein per kilogram of body weight each day tend to get stronger on average than those who eat less than that amount, based on improvements in their squat, bench press, and deadlift numbers over 8 weeks.

For young guys lifting weights, eating 1.8 grams of protein per kilo of body weight each day is enough to gain muscle and get stronger in 10 weeks — it doesn’t matter if they take a 35g casein protein shake during the day or before bed.