Continuing my last post about post-run nutrition... some years ago there was a recovery product available by the name of JogMate. It contained whey protein and casein both, plus carbs, and came in a tube.. like a small tube of toothpaste, which was very convenient to take along with you to wherever your workout or race happened to be. Jane and I would make sure we had one after all our long runs, hard workouts, and races (if we remembered); it did seem to make our legs feel more springy and less heavy in the next couple days than before we started using it. At the time, there were no studies on any recovery products, and we didn't know anyone else besides us who used JogMate.
Research began to come out in 2006 that a glass of
low-fat or fat-free chocolate milk provided just the right ratio of carbs to protein
(4:1) that, if ingested within 30 minutes of your workout, was ideal for muscle recovery and glycogen replenishing, better than ingesting carbs alone. You can read a couple articles about it here and here.