I'm not really gaining weight, but I am putting muscle back on, slowly, in the gym four-five days a week. Part of the reason I'm not gaining is that some pockets of flab are falling away as I regain strength.
In any case, I've found I tolerate the PaleoMeal Whey Protein powder very well (http://www.amazon.com/Designs-...Powder/dp/B000ML917K)