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, as long as they’re already eating enough protein overall.

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.

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.

If guys who already lift weights drink a 20g protein shake after working out for 9 weeks, they’ll gain more muscle and get stronger—even if the protein is a mix of fast- and slow-digesting types.

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 can get noticeably stronger in their legs after 12 weeks of weight training.