Milk may knock you out of ketosis because of the lactose - milk sugar. It's a bit like the citric acid thing, some people are more sensitve than others. I'm not a milk fan at all, and haven't touched a drop since I started at the end of September, including the break week at Christmas. I'm not big on dairy at all and have suffered in the past from the effects of low calcium but have not had anything at all since starting. 4 packs or 3 packs and a multivit seem to be considerably better nutritionally than my previous diet!