There was a period of time when I could digest whey shakes (mixed with milk), then all of a sudden it changed and I started getting strange reactions a few times in a row (with the same exact whey, mixed with milk), so I dropped it. I've also tried a protein bar recently and I had the same reaction I had with the whey. I start getting heartburn-like symptoms, and I start producing a shitload of mucus in my throat that I need to spit out multiple times. Very uncomfortable. I used to be lactose-intolerant as a little kid, but for awhile now I've been able to digest milk.