I've always tried to keep fit by adding weights (curls, bench, etc.) 4-5 times/wk since I was a young teenager. I always tried to eat healthy and my wife does a good job ensuring that now.
However, I have noticed my body muscle mass has "shrunk" a bit over the last few years but at 60yo (now) that's to be expected somewhat.
I recently started adding a serving of whey isolate powder into my daily routine and have to admit that my work-outs the last 4 wks have been more positive. ie less aches, more endurance, quicker recovery etc.
May be just in my head but I'm going to continue taking the whey isolate as a supplement to my meals.....