It seems that no one in America is immune to the obesity epidemic – not even infants! A study published in the July issue of the journal Obesity found that the percentage of infants who are significantly overweight rose 73.5% over the past 2 decades. Using medical records of more than 120,000 pre-school children from primarily middle-class families in Massachusetts who visited doctors from 1980-2001, researchers found that the observed prevalence of overweight increased from 6.3% to 10.0%. Most striking, these increases were evident in all groups of children, including infants < 6 months of age! More specifically, the percentage of overweight babies <6 months old (defined as weight-for-length ≥ 95th percentile, specific for gender and age in months) jumped from 3.4% to 5.9%.
Although the rate of overweight infants is still below the rate in older populations, the trend is very worrisome because there is accumulating evidence that accelerated weight gain in early life is a risk factor for weight problems and higher blood pressure later in life. As Dr. Nicholas Stettler, assistant professor of pediatrics and epidemiology at Children’s Hospital of Philadelphia, explained, “If you look at weight gain early in life – during the first year, the first four months, even the first week -- and then you look at weight status in childhood and adulthood, you find a strong association.” Thus, the trend of increasing weight among young infants may predict a continued increase in childhood an adult obesity.
This is an important study because this young age group is seldom included in weight studies. Although this study didn’t examine the reasons behind the increasing rate of fat babies, several other trends may partly explain it. More babies are born large for their gestational age as more women are overweight before they become pregnant and more women develop gestational diabetes. In addition, more babies are rapidly gaining weight during the first few months of life. There are several plausible explanations behind these alarming trends. It could be that overfeeding in early life reprograms a person to overeat by affecting the brain’s neurochemical development. Alternatively, insulin secretion and metabolism could be altered by overfeeding during early development. Another hypothesis is that the genetic component of being overweight may first express itself during infancy and remain a risk factor throughout life. Or, humans may learn to override their innate feeling of being satiated if food is offered even when they are not really hungry.
So, while those chubby cheeks may be cute, they may also indicate that, “even our youngest children are not exempt from the well-documented trends of over-weight seen among our older children and adults in the United Sates,” as this study concludes. As Dr. Gillman, one of the study’s authors, says, “Our obesity prevention efforts need to start at the earliest stages of human development.”