I just had this weird experience once that has been in the back of my mind. Often when I work out after going a long period without doing it, I'll be sore for days. In extreme cases, even a week.
In one instance, I went hiking with my ex and hadn't used my legs in months. We climbed up and down a mountain and my legs were so tired by the time we made it back to our tent at the bottom that I could barely even stand. Usually I would expect that kind of experience to leave me sore for a week.
Even worse, I had forgotten to bring any meat for us to eat. All we had was vegetables, beans, fruits and nuts. I made myself eat the stuff since it was all we had but I fully expected to be sore for an entire week.
The next day, my legs weren't sore at all. I had full range of movement and seemingly of endurance. The only explanation is that beans and nuts etc. did more for me than my usual beef and protein shake combo after such a thing would have. This was one of the experiences which made me really start to wonder about the type of diet I live off of.