I use Whey Protien Isolate from SupplementDirect.com
I have only noticed an increase in the amount of times I shit when I think I injest too much.
I take 1 shake of 1/3 cup of Whey, 1 scoop of glutamine and creatine at 4:30am
I just started mixing in some Whey with my 2% milk during breakfast @ 7:30 (when I added this into the mix... I buy 16oz milks and I put Whey in both and I noticed a defnite increase in how much I shit. However when I only add Whey to 1, and not both... all seems well)
I take a PWO shake of 1/3 cup of whey, 1 scoop of creatine and glutamine, and some Dextrose (varies depending on how I feel that day, cause personally I hate that shit) usually this is around 4:30pm
Then I may have another shake sometime around 8ish depending upon my hunger level at that time.
It seems for me that its relevant to how much I take in.