I used to be a vegan for almost 8 years (omg, I can't believe I was so damn hungry for years and didn’t know it haha). When made the jump I noticed that I didn’t have the problems adjusting to meat as much as I did to dairy.

You will notice, less problems with cultured dairy products (for obvious reasons, they're cultured). I guess ice cream would be a bit problematic, as it is very rich. The problem is that the body is no longer used to digesting dairy and has stopped producing certain enzymes because they weren’t needed on a vegan diet. The best thing I can recommend from my experience is start out by reintroducing dairy to you body slowly at first, mostly with cultured dairy products as some proteins in them are already partially broken down by the culture. Drinking milk is probably the hardest, which I often experienced cramping and/or gas with. The key is to reintroduce, but slowly, so that your body begins to rebuild its tolerance and ability to digest.

What's interesting is that I was talking with a doctor friend of mine and I mentioned how in middle-eastern, Mediterranean and Latin countries there is a high occurrence with lactose intolerance and dairy related digestive issues. In these cultures there is a legacy of late breastfeeding, sometimes as late at 3 or 4 years old. Interestingly as well is the fact that they groups consume a great deal of goat derived dairy. He seems to agree with me that it's quite possible that dairy intolerance is more common due to lack of introduction to cow derived early in life.