^ Key, T. J.; Fraser, G. E.; Thorogood, M.; Appleby, P. N.; Beral, V.; Reeves, G.; Burr, M. L.; Chang-Claude, J.; Frentzel-Beyme, R.; Kuzma, J. W.; Mann, J.; McPherson, K. (September 1, 1999). "Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies". The American Journal of Clinical Nutrition. 70 (3 Suppl): 516S–524S. doi:10.1079/phn19980006. ISSN 0002-9165. PMID 10479225.
Dairy products contain varying amounts of lactose (milk sugar), which slows down weight loss. What’s more, part of the protein in milk generates a significant insulin response, which can have the same effect. Consequently, cutting back on dairy products may accelerate weight loss. This applies especially to dairy products typically lacking in fat, such as regular milk and various yogurts, but be careful with full-fat dairy such as cream and cheese all the same. And don’t forget whey protein powder, which is pure milk protein.