The battle this week in San Francisco between fast food giant McDonald’s and the advocacy group Corporate Accountability International has reignited conversation about the various risk factors associated with childhood obesity. To many this seems like the 20th round of the same old fight, as most people are familiar with the major contributors to the childhood obesity epidemic. However, in the November 2011 issue of Archives of Pediatrics & Adolescent Medicine researchers from Harvard Medical School published an article highlighting yet another determinant of obesity in children.
In this study the authors examined patterns of weight gain in infants during the first 24 months of life. Children at this age frequently visit the doctor’s office for routine check-ups. During these visits their child’s weight to length is recorded as a percentile of the national average. For example, if Suzy falls into the 25th percentile that indicates that 75% of children in the country have a higher weight to length ratio than Suzy. The authors examined whether children who experienced dramatic increases in their weight to length percentile during a 6-month interval were more likely to be obese during later stages of childhood.
The experimenters found that 43% of children show dramatic increases in their weight to length ratio during the first 6 months of life. After the first 6 months these substantial increases are less common, with only 14% of children from 12-18 months and 11% of children from 18-24 months experiencing similarly large gains. As expected, children that started out at a very high percentile were more likely to be obese at ages 5 and 10 years. Interestingly, the authors also found that substantial gains in the weight to length ratio is also linked to an increased risk of obesity, particularly in children who started out in a high percentile.
Of course, the purpose of this study is not to suggest that infants should be dieting. Instead, since there is no evidence that infants are prone to overeating, the results of this study may serve as evidence for the role that genetics can play in obesity. Perhaps even at this young age there are differences in metabolism and energy storage that are indicative of problems later in life. In addition, it is important for parents who use baby formula to pay close attention during doctor visits as some formulas are associated with increased weight gain in infants.
