Quotes of the Day

It's already a tough decision for any parent, but opting for child care may have just become an even weightier issue. Researchers at the University of Illinois and the Harvard School of Public Health report that toddlers who spend time in day care tend to gain more weight than those who are cared for by their parents at home.

After scouring a national database of more than 8,000 infants who were nine months old between 2001 and 2002, researchers Juhee Kim and Karen Peterson found that about 55% of infants were regularly cared for by people other than their parents — in other words, relatives or professionals at a child-care facility. Half of those children were in full-time day care, 40% of them beginning at younger than three months of age. The researchers found that the babies who received day care gained, on average, 175 g (about 0.4 lb) more over nine months than babies being raised exclusively by their parents. In addition to being heavier, these infants also started eating solid foods earlier than babies under parental care. "We were surprised by the quantity of weight gain," says Kim, a kinesiologist at University of Illinois and an author of the study published this month in the Archives of Pediatrics & Adolescent Medicine.

Kim notes that babies enter a critical period between three and six months, when parental bonds are firmly established and when many infants begin transitioning from milk to solid foods. Kim acknowledges that it's still not clear what causes weight gain in babies in day care, but she speculates that it may have something to do with their irregular eating patterns and caregivers' different feeding habits. Infants who are cared for at home, for example, can expect a constant and consistent feeding pattern. But a baby who spends her days in day care may get fed every time she cries, as a soothing mechanism. "We need to look at feeding practices more carefully — not just what the babies are eating, but the feeding environment," says Kim. "If children are cared for by their parents, they are exposed to only one environment. But if they are put in a child-care setting, then they have two different environments and two different feeding patterns. That might be a factor for more weight gain."

Past studies have shown that day care can enhance or accelerate babies' cognitive development; it may even boost their academic performance later in life. But eating habits established during this same time may also have long-lasting — and unhealthy — effects. Kim believes early feeding habits may contribute to the growing obesity epidemic among the youngest infants. "We need to answer the next questions that this study asks," she says. "What types of food are babies in child care eating? When are they fed? How are they fed? Are they eating higher calorie foods or just eating more often? We don't know anything about this yet." The answers to those questions might lead to some much needed guidance for shrinking the expanding waistline of American children.

• Alice Park