Older guys between 60 and 75 who aren't very active can get a lot stronger in just 12 weeks by lifting weights twice a week—even if they don’t take extra protein right after workouts or before bed,...

Older guys (60–75) who already eat enough protein don’t get stronger or build more muscle from extra protein shakes, even if they drink them after working out or before bed—just lifting weights is enough.

For older guys in their 60s and 70s who already eat enough protein, taking 40 grams of protein right after working out or just before bed doesn’t help build bigger leg muscles any more than just working out — the muscle gains are about the same no matter when they take it.

In young men who lift weights recreationally, eating more than 2.0 grams of protein per kilogram of body weight per day led to slightly greater increases in strength over 8 weeks compared to eating less, even though muscle size increased similarly in both groups. This suggests that strength gains may come from improvements in how the nervous system controls muscles or in lifting technique, rather than just from muscle growth.

If older guys who are already active do full-body strength training three times a week for three months, they’ll get stronger legs and bigger leg muscles—even without adding extra protein to their diet.

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.