Milk consumption is down around the word, with Americans reducing their intake by 37 percent since 1970. And whole milk consumption has dropped by 78 percent in that same time period, according to the Washington Post. It's still an important beverage for child development, though, and new research seeks to answer an important question: which milk is best for you? Well, going against the conventional wisdom, Canadian researchers have found that children who drink whole milk statistically had lower body mass indexes than children who drank one-percent milk or skim. The research also suggests that the children who consumed the higher-fat-content milk had higher levels of vitamin B, too.

The methodology was as follows, according to the New York Times

Researchers collected height and weight data on 2,745 healthy children ages 1 to 6. They took blood samples, and their parents reported how much skim, 1 percent, 2 percent, and whole milk the children drank. 

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.

The Cliffs Notes version: Somehow, drinking milk with higher fat content could help fight childhood obesity.

The study, which appears in the American Journal of Clinical Nutrition, was authored by Dr. Jonathan Maguire, an associate professor of pediatrics at the University of Toronto. Dr. Maguire suggests the reason for this is that vitamin D may be more easily absorbed by the body when in fat, and low-calorie milk may leave children hungrier and thus more likely to seek out high-calorie foods. This makes sense as several cups of 1 or 2 percent milk could take up around 40 percent of a child's daily caloric intake, while leaving them hungry still and causing them to overeat and consume more calories than is recommended.

Now, this is useful because Americans, children especially, drink a lot of milk. This is a good thing because, as Dr. Maguire, told the Times back in October, "Cow's milk has been a staple in the diet of children in North America for a long, long time and is loaded with essential nutrients and energy" like protein, calcium, and the aforementioned fat and vitamin D. These reasons probably account for the worldwide increase in demand for milk, and even though prices have gone up, it's still a really affordable grocery item. The increase in price of milk has lead to people drinking less, but that might not be so bad since you shouldn't be drinking too much milk, anyway. Again, according to Dr. Maguire, children who drink more than two cups a day see increased vitamin D, but also increased iron deficiency. 

Circling back to his new research, it stands to reason that the children who drink two cups of whole milk will also have higher iron levels. So, whether it's with a bowl of cereal, or during dinner, give whole milk another shot. Maybe it's the default milk for coffee for a reason.