Does low-fat milk make kids heavier?

U. VIRGINIA (US) — Preschoolers who drink low-fat milk are more likely to be overweight or obese than kids given 2 percent or whole milk, new research suggests.

The new study evaluates data from 10,700 American children between the ages of 2 to 4 followed in the Early Childhood Longitudinal Study.

The findings, published online in Archives of Disease in Childhood, show that consumption of 1 percent and skim milk is most common among preschoolers who are overweight or obese—possibly reflecting parents’ concern about their children’s weight.

However, the study also shows that the low-fat milk didn’t restrain children’s weight gain between ages 2 and 4. In fact, children given skim or 1 percent milk were more likely to become overweight or obese during that time than their peers who drank whole milk. Over time, the kids drinking low-fat milk gained weight at a similar rate as children drinking 2 percent or whole.


“The association (between the consumption of low-fat milk and obesity) was really striking, in that it was present in every single racial ethnic group and every single social strata. So it was quite consistent,” says Mark D. DeBoer, a researcher at the University of Virginia.

“And it was also (noted) at both 2 years of age and 4 years of age. The children who drank skim were the heaviest, then 1 percent, then 2 percent, and then whole milk. Children who drank whole milk had the lowest weight score.”

Researcher Rebecca Scharf was inspired to evaluate the relationship between milk consumption and children’s weight after noting the growing obesity problem in New York City.

“I thought it would be interesting to run the data and see if the children who drank only high-fat milk are more likely to be obese, because we were seeing lots of obesity in the neighborhoods where skim milk was not readily available,” Scharf says. “As I started to run the data, I found that it was exactly the opposite: Children who drank low-fat milk were heavier.”

To combat the epidemic of obesity among youth, both the American Academy of Pediatrics and the American Heart Association have advocated giving low-fat or skim milk to all children ages 2 and older.

But the new research suggests that tactic may need to be reconsidered in favor of emphasizing more conclusively effective means of weight control, such as increased exercise and decreased television viewing.

“The amount of calories you take in versus the amount you spend—your balance of calories—is going to determine how much you weigh,” DeBoer says. “So the logic has always been, you should drink skim milk because you’re taking in fewer calories.

“The problem is that only applies to the milk portion of your diet. If drinking whole milk makes you full, so that you aren’t hungry to eat a bag of chips, then that overall would cause you to have fewer calories going in. So there is the possibility for whole milk being a better satiety agent and holding down other calorie consumption.”

The message parents should take from the study is that the type of milk children consume matters much less than other lifestyle factors.

“For a long time the American Academy of Pediatrics and pediatricians have been trying to get people to drink skim milk, and that’s probably not a strong strategy,” DeBoer says.

“We should focus on other things, like not eating as many snack foods, not eating foods high in saturated fat, decreasing soda consumption, decreasing television watching. Those are things with a stronger evidence basis.”

Ryan Demmer of Columbia University is a co-author of the study.

Source: University of Virginia