SKIM MILK WAS ALWAYS SHADY: Regular Milk May Beat Low Fat for Kids. “After controlling for age, sex, outdoor play and other factors that affect both vitamin D levels and weight, they found that children who drank one cup of whole milk per day had a vitamin D level comparable to that of children who drank 2.9 cups of 1 percent milk, but their body mass index was lower by 0.79 points. The higher the fat content of the milk they drank, the lower the children’s B.M.I. and the higher their vitamin D levels.”