Based on the evidence, we know the proportion of children impacted by overweight or obesity increased significantly from the 1970s to 2000s, and approximately one-third of children are currently classified as such.
However, we know much less with regards to recent trends… how has the prevalence of childhood overweight and obesity changed over the past 15 years?
Two recent studies, one on American children and one on Canadian children, have focused on this question. According to Canadian data, the prevalence of overweight and obesity among children has decreased (30.7% to 27.0%) during this period, with obesity rates remaining relatively stable* (13.0%). Conversely, data on American children has reported a “clear statistically significant increase across all classes of obesity in children.”
It should be noted that expert in the field, Bill Dietz, says we need to be cautious when making these conclusions. In his recent commentary, Dietz states that such findings all depend on how the data is ‘anchored’. In other words, the date (e.g., 1999 vs. 2003) that is denoted as the starting year of analysis and therefore the point of reference.