make it yourself protein powder using gelatin
I make no claims on this because I haven't tried it, but it would be good for HE, def. better than the commercially available protein powders.
Protein Workout Recovery Shake Using Gelatin | Primally Inspired
Also, the brand of gelatin they recommend is kosher and is supposed to melt a lot better in gelatin juice, I'm going to be recommending this type from now on (in the green box, not the red) because i know a lot of gals are struggling with the Knox gelatin. Available for much cheaper from the company, don't order off Amazon
Great Lakes Gelatin | Collagen Joint Care for Consumers