Along the same lines; for the longest time I suspected artificial sweeteners were causing me some kind of harm as it pertains to digestion, bloating, and frequent urination. I stopped my intake of diet drinks a few years ago, but my protein powder is sweetened with sucralose. Almost 20 years of shakes like other people here too. Well, I finally decided to buy unflavoured whey isolate and a few things happened:
I noticed it tastes fine. In fact, I prefer it. None of us knows how much sucralose or whatever is in each scoop. The labels just say what it's sweetened with. So our intakes could be very high.
Within four days I was weighing 3-4 lb less on the scale, my stomach wasn't as bloated visually, and my lifting belt fits tighter. I'm also not running to the bathroom as much either. All sweeteners, even stevia, cause me bladder irritation and I found out other members in my family had the same issue.
So if anyone dropped whey on the hunch that it was the dairy causing them problems, try unflavoured. It may have been the sweetener.