yea i get it when i eat alot of tuna on its own, if you wanna bulk and youre not exactly fat then you can chuck in a load of carbs too, pasta has helped me alot (gained 1 st in 1 month) and seems to neutralise any discomfort if im eatin alot of tuna at the same time
the thing i find with protein is that it fills me up yet i can eat a family sized pack of pasta with a full jar of ragu or whatever and still have room for more food, theres only so much protein your body can digest so you might aswell fill the rest with carbs, you dont have to go mega low fat either (cottage cheese)
just eat what you would normally eat but double it
The pain could also be from a "backup" in your digestive system, a high-protein diet can sometimes cause constipation. If you're eating alot more, you should be *censored* alot more, are you?
Bingo. I get the same thing because I eat a lot of protein. Pick up some metamucil. Or you can do what I do and just get some fiber pills for 5 bucks at the pharmacy. Take two a day and it'll clean that sucker right out. You'll be feeling better in a couple of days.