this happens to me too. it doesn’t matter which brands of protien powder i use, the quality or anything. i think it happens when you just eat too much protien. people recommend between .5 grams and 2.0 grams of protien per pound of lean body weight depending on who you talk too, yet nobody knows for sure how much is actually enough.
my theory is that recommendations go along the lines of “too much is better than not enough” and many of us wind up eating so much that our bodies just shit it out.
try cutting back a tad on the protien. you’ll still get gains and you may cut back on the shits and gas.
listen to your bodies signs and stop overloading it.
also, try apple cider vinegar. i’m not personally a fan of supps other than whey after a work out and now HOT-ROX, but i tried the stuff when i was sick on my girlfriends, grandmothers suggestion after over the counter medicines didn’t work and it cleared me right up.
i researched it and found it does all kinds of cool shit, mostly it helps with digestion by making your stomach more acidic, which could help breakdown more of the protien you are eating.
it smells like real vinegar and tastes like shit, but once you get used to it, it is ok.
you should look in to it. you’ll be glad you did.
try this link, it is from a retailer due to search optimization, but if you do your own research you’ll find their info is accurate from independent studies too.