Baby Fat May Not Be So Cute After All

Schools have banned cupcakes, issued obesity report cards and cleared space in cafeterias for salad bars. Just last month, Michelle Obama’s campaign to end childhood obesity promised to get young people moving more and revamp school lunch, and beverage makers said they had cut the sheer number of liquid calories shipped to schools by almost 90 percent in the past five years.

But new research suggests that interventions aimed at school-aged children may be, if not too little, too late.

More and more evidence points to pivotal events very early in life — during the toddler years, infancy and even before birth, in the womb — that can set young children on an obesity trajectory that is hard to alter by the time they’re in kindergarten. The evidence is not ironclad, but it suggests that prevention efforts should start very early.

Among the findings are these:

- The chubby cherub-like baby who is growing so nicely may be growing too much for his or her own good, research suggests.

- Babies whose mothers smoked during pregnancy are at risk of becoming obese, even though the babies are usually small at birth.

- Babies who sleep less than 12 hours are at increased risk for obesity later. If they don’t sleep enough and also watch two hours or more of TV a day, they are at even greater risk.

Some early interventions are already widely practiced. Doctors recommend that overweight women lose weight before pregnancy rather than after, to cut the risk of obesity and diabetes in their children; breast-feeding is also recommended to lower the obesity risk.

But weight or diet restrictions on young children have been avoided. “It used to be kind of taboo to label a child under 5 as overweight or obese, even if the child was — the thinking was that it was too stigmatizing,” said Dr. Elsie M. Taveras of Harvard Medical School, lead author of a recent paper on racial disparities in early risk factors.

The new evidence “raises the question whether our policies during the last 10 years have been enough,” Dr. Taveras said. “That’s not to say they’ve been wrong — obviously it’s important to improve access to healthy food in schools and increase opportunities for exercise. But it might not be enough.” Much of the evidence comes from an unusual long-term Harvard study led by Dr. Matthew Gillman that has been following more than 2,000 women and babies since early in pregnancy.

Like children and teenagers, babies and toddlers have been getting fatter. One in 10 children under age 2 are overweight. The percentage of children ages 2 to 5 who are obese increased to 12.4 percent in 2006 from 5 percent in 1980. Yet most prevention programs have shied away from intervening at very young ages, partly because the school system offers an efficient way to reach large numbers of children, and partly because the rate of obese teenagers is even higher than that of younger children — 18 percent.