To many people, a chubby baby is a healthy baby. But a new study may be calling that age-old belief into question. A group of researchers at Harvard Medical School looked at nearly 45,000 infants and children over a 28-year period, and found that babies who grew very quickly in the first two years of life were more likely to be obese later on. The study, which was published in Archives of Pediatric & Adolescent Medicine, found that babies who jumped two or more height-and-weight percentile milestones by the age of two were twice as likely to be obese by age five as their slowergrowing counterparts. Interestingly, the study also found that the highest obesity rates in later childhood occurred in babies who jumped two milestones in the first six months of life.
While some doctors have lauded the study for calling attention to the much-publicized “childhood obesity epidemic” happening across North America, others say the study itself is cause for concern – could it prompt nervous parents to put their babies on a diet?
“There’s no doubt about it, the trend toward heavier kids in our society is not acceptable,” says Dr. Janine Flanagan, a developmental pediatrician at St. Joseph’s Health Centre in Toronto. “And yes, identifying the problem early is a good thing. But where I got my back up with this study is that they were even looking at the first six months. During that time we actually expect rapid growth – it’s quite normal, and it’s good. And no one would ever, ever put a baby under one year old on a ‘diet.’”
Dr. Flanagan says where she starts to be concerned about obesity is between the ages of one and two, and she says rapid weight gain during that period can almost always be attributed to consuming excessive amounts of liquid from the bottle. “These babies are drinking bottles and bottles of milk or formula. The weight gain is not from the solid food they’re eating. Almost all the time, it’s the bottle that is making them fat. Ideally, you want to get them off the bottle by the time they’re a year old, and focus more on solids, with liquids to wash their food down at mealtimes.” Heavier babies in that age range are often not getting enough exercise, either. “They’re always being carried around or pushed in a stroller, and they need to walk and crawl more.”
While an increased awareness about childhood obesity is a good thing, Dr. Flanagan says this study could cause potential harm. “The unintended consequence is you have parents who stop providing adequate nutrition to their children. There’s a fine line between alerting parents and alarming them so they restrict food in a young baby.”
When should I introduce solid foods?
The Canadian Pediatric Society (CPS) and the World Health Organization – recommend exclusive breastfeeding for the first six months of a baby’s life.
However, the American Academy of Pediatrics (AAP) has recently changed its recommendation to “about four to six months” to allow for the introduction of solid foods, and the CPS is working to follow suit, says Dr. Janine Flanagan. “We’re going back to recommending introducing solids at four months, which is what used to be the recommendation. The main reason for this is that by delaying solids until six months, there is an increased risk of allergies in children.”
Between four and six months is the baby’s “oral tolerance window,” says Dr. Flanagan, in which the body learns to accept most foods and not reject them as foreign. “If a child is not exposed to certain allergens before six months, they are more likely to become allergic to them. We’re breeding this population of highly allergic kids because we’re missing this window.” The concept that introducing solids early causes obesity? “That’s absolutely untrue,” says Dr. Flanagan. "Starting solids earlier has absolutely no link to obesity.”
Originally published in ParentsCanada, May/June 2012