Seriously.
In 1999 a new exercise recovery drink was introduced: EnduroX R4. I tried it and found, like most, it worked far better than anything on the market. It contained 4 ingredients commonly found in such drinks plus a patented 4:1 ratio of carbohydrates to protein. The drink was expensive. Eventually somebody noticed chocolate milk had the same 4:1 ratio. Turns out it's that ratio, plus drinking immediately after exercise, that accounted for most of EnduroX R4's superiority.
Scientists got interested. They've confirmed athletes' subjective impressions. For example: http://www.ncbi.nlm.nih.gov/pubmed/23075563
I've been pushing my walking distance enough to need some sport drink refueling. Tried flavored milk. It works. Most Thai chocolate milk has too much sugar for the correct ratio. I found a banana flavored milk who's brand I don't remember was the closest to 4:1. Milo was next closest at 4.75:1.