You can eat slowly and in small amounts. First of all, the human body needs protein, that's for sure!

Diarrhea should not be lactose intolerance. Lactose intolerance often occurs when drinking milk. See if there are any dairy products in your protein powder. If there is, eat more!

If not, we should consider our own digestion and absorption. If the protein powder is of good quality and high content, if you eat it suddenly, your stomach can't stand it and you have diarrhea!

I hope it helps you!