Anyone else having diahrrea? I thought I would be constipated, but having the opposite problem My pain is getting better, now feels like a chronic stitch in my left side -- but having trouble getting enough protein down. I hate all the protein drinks I've tried except for Atkins. I like Carnation Instant sugar-free breakfast, but wondering if the milk is causing my diahrrea? How do you know if you're lactose intolerant?