Parents may need to monitor their newborn baby’s weight gain carefully, as part of an ongoing Harvard Medical School study found that significant weight gain during the first six months of life may put a child at risk for obesity by age three.

While the link between birth weight and obesity has previously been investigated, this study is the first to look at weight gain in the first few months of life and brings into question the effectiveness of current health care policies, which are largely aimed at school-age children.

“There is increasing evidence that rapid changes in weight during infancy increase children’s risk of later obesity,” explained lead author Elsie M. Taveras, a professor of Ambulatory Care and Prevention and Pediatrics at HMS and co-director of the One Step Ahead clinic at Children’s Hospital Boston, in a HMS press release. “The mounting evidence suggests that infancy may be a critical period during which to prevent childhood obesity and its related consequences.”

During the past 20 years there has been a dramatic increase in obesity in the United States. Currently, one in three children is overweight or obese–a statistic President Barack Obama and First Lady Michelle Obama are citing in creating the “Let’s Move” program to end childhood obesity. Additionally, one in 10 children under the age of two is overweight or obese.

However, obesity prevention programs for infants and toddlers have been avoided so far.

“It used to be kind of taboo to label a child under five as overweight or obese, even if the child was–the thinking was that it was too stigmatizing,” said Taveras in a New York Times article.

The new evidence suggests that although recent policies have not been incorrect, they could be described as too little, too late.

As Dr. Taveras stated in the press release, “the earliest interventions will have the greatest long-term benefits.”

The study was published in the journal “Pediatrics” last year.