American children are eating slightly less than they did a decade ago, according to a new study released by the Centers for Disease Control (CDC). Experts say the small decline, 7% to 2,100 calories a day for boys and 4% to 1,755 calories a day for girls, suggests that we may be getting over our collective weight problem, though it's too early to tell.
It's certainly a good thing that children are eating less, but what's more important is that they're eating fewer carbohydrates, which are arguably the most fattening part of their diets.
The CDC found that, “Among children and adolescents aged 2–19, the percentage of kilocalories from carbohydrate for boys decreased from 55% in 1999–2000 to 54.3% in 2009–2010 and for girls from 55.8% in 1999–2000 to 54.5% in 2009–2010.”
The numbers by themselves aren't all that impressive, but they're still significant. In the three decades preceding the period studied by the CDC, childhood obesity in America tripled while consumption of carbohydrates increased drastically, according to a study published in 2000. Interestingly, all of the foods typically blamed for childhood obesity — soda, candy, and fast food — are loaded with carbohydrates.
That's certainly an interesting correlation, but the clinical evidence also suggests that carbohydrate consumption drives childhood obesity. In a trial published last July, researchers put 58 adolescents on a low-calorie or low-carbohydrate diet. The latter group lost more weight and experienced bigger improvements in their metabolic health. A 2003 study similarly found that adolescents on a low-carbohydrate diet lost more weight than those on a low-fat diet. A third study, published in 2010, also found that severely obese adolescents fared better on a low-carbohydrate diet. And there are plenty more studies (18 so far) demonstrating that overweight and obese people, however old they are, do well on low-carbohydrate diets.
Backed up by these clinical trials, the declines reported by the CDC are encouraging, but there's one important caveat worth mentioning: the agency's results are based on food recall surveys. The “information on nutrient intake was obtained from one 24-hour dietary recall interview administered in-person...” which makes it likely that some of those surveyed underestimated how much they eat in a day. But as New York University researcher Brian Elbel told the New York Times, even if people underestimated how much they eat, there was still a decline between the numbers reported in 1999 and 2010, so the trend is probably real.
The CDC say they'll continue to collect data on childhood obesity to see if the trend continues. And since we have decent evidence that carbohydrates are the problem, hopefully people will continue to eat fewer of them. In the meantime, perhaps we should all do our part by eating more bacon and fewer Snickers bars.