MANGAN: The Victorians were still cleverer than us, or the road to Idiocracy? “There may be biological, non-genetic factors that have contributed to dumber people, for instance the low-fat diet craze, endorsed and promulgated by USG. The human brain is nearly 60 percent fat. Depriving the brain of essential fatty acids up to the age of 5 or 6 – and probably a lot longer if you ask me, but nobody is – means that the brain may very well not develop properly. If you think this is not a problem, take a look at the fat content of typical infant and toddler food, which is pathetically low. The American Academy of Pediatrics says that restricting fat can harm brain development in children, yet I would bet that many parents, especially from the more educated classes, have been doing just that for the past several decades.”

But even the AAP recommends in its own materials to begin restricting fat intake at age two, or even earlier. See the above link, or page 228 of “Bright Futures: Nutrition Tools” [PDF p.8], under the “Milk and milk products” section:

Children ages 1 to 2 need whole milk. After age 2, children should gradually increase the proportion of low-fat foods in their diets. For children older than 2, low-fat (1%) or fat-free (skim) milk is recommended. Reduced-fat milk (2%) is recommended for children ages 1 to 2 years for whom obesity is a concern or who have a family history of obesity.

Surely, if the AAP recommends cutting back on baby’s fatty milk at age two to avoid obesity, there must be good evidence supporting this, right? Wrong:

“Our original hypothesis was that children who drank high-fat milk, either whole milk or 2%, would be heavier because they were consuming more saturated fat calories. We were really surprised when we looked at the data and it was very clear that within every ethnicity and every socioeconomic strata, that it was actually the opposite, that children who drank skim milk and 1% were heavier than those who drank 2% and whole,” says DeBoer, who is also the chair-elect for the AAP Committee on Nutrition.

DeBoer says when they broke down the data into the different types of milk with increasing fat content, the findings were even more striking. As BMI scores went up among the kids, the amount of fat in the milk they were drinking went down. “So the ones drinking skim were by far the heaviest, and those drinking whole milk were the lightest,” he says.