For at least the last four decades, we’ve watched obesity rates skyrocket, first in the developed world, and subsequently across the globe. The United States have been leaders in this department, with some of the highest rates of obesity in the world. For the first time, it appears that the rate of obesity has finally achieved a plateau in our southern neighbors.

In last week’s issue of the Journal of the American Medical Association, Katherine Flegal and colleagues published a study examining the trends of obesity and overweight in the US from 1999 through 2008. Using a representative sample of over 5,000 people from the National Health and Nutrition Examination Survey in 2008, they found that 72.3% of American men were overweight, and 32.2% qualified as obese (by BMI >30). Women weighed in with a slightly lower rate of overweight at 64.1%, but a numerically higher rate of obesity at 35.5%. When these numbers are compared to data over the years previous, there is no significant rise in the rate of obesity over the last 10 years for women, or over the last 3 years for men.

In the same issue of JAMA, a similar study by Ogden and colleagues suggested similar stability in the prevalence of obesity in children, except amongst the very heaviest of boys, where the obesity rates do continue to increase.

So, does this mean that the world can breathe a sigh of relief that the obesity epidemic may be slowing? Well, it is surely a good thing that the rates in the US are topping out – if the rates of obesity in America had continued on its previous track, the World Health Organization predicted that almost half of US adults would be obese by the year 2020. Having said that, at the current prevalence of obesity of one third of the American adult population, the impact is still staggering. With obesity comes an increased risk of diabetes, heart disease, and cancer, to name a few; in 2008, obesity related disease was estimated to account for 10% of total American health care expenses. Thus, a plateau in obesity rates is not enough – the next necessary step is to effect a decrease in rates of obesity, in order to decrease the rates of these other dangerous diseases and create a healthier population overall.

The above data is not a sign for the rest of us in the world to relax, either. Obesity rates remain staggering in many countries around the world, and the prevalence continues to increase in many places, particularly in developing nations, where the introduction to unhealthy western eating habits is still relatively new. One also wonders whether the plateau in American obesity rates reflect a positive impact of health care initiatives to educate and prevent a further rise in obesity rates, or whether this may reflect a genetically determined saturation of obesity in that population. Regardless, one lesson that we can all take home from these observations is that in a sedentary environment with oversize portions and a plethora of unhealthy food choices, the majority of us will become overweight; let us hope that education, motivation and inspiration are truly powerful enough to stop it.

Dr. Sue © 2009