While you have to challenge the muscle to get it to grow, what you feed it is just as, if not more, important. You never have to overdo it on protein but it is very important to get it from good sources. NATURAL SOLUTION offers a great list here, even though I would challenge the suggestions on protein powders. As they say in the video, “dairy protein powders, such as whey and casein, are some of the most popular”. Being popular doesn’t make you the best choice. There are plenty of plant based proteins to choose from to stay away from dairy. Of course, my choice is Juice Plus Complete and Juice Plus Perform!