In her book Health at Every Size: The Surprising Truth about Your Weight (reviewed here) Linda Bacon recalls her days as a PhD candidate. This was also when the BMI standards were lowered, and, coincidently enough, her mentor, Judy Stern, was a member of the NIH Obesity Task Force.*
When I expressed my surprise of the standards being lowered, she encouraged me, as an academic exercise, to conduct a review and make recommendations as if I were sitting in her place on the task force.
A careful review confirmed my suspicions. There was significant evidence in support of raising the standards, not lowering them. I presented my review to my mentor, who laughed and congratulated me on my insightful analysis.
I asked the obvous question of why the Obesity Task Force recommended lowering the standards in the absence of supporting data. I paraphrase her response: “We were pressured to make the standards conform to those already accepted by the World Health Organization.”
In other words, this decision was made for political reasons, not because it was supported by science or for the betterment of public health.
Bacon further notes that the WHO report that helped define 25 as the BMI boundary between “normal” and “overweight” was largely the work of the International Obesity Task Force, which is largely funded by the makers of Xenical and Meridia.
*According to the Washington Post, Judy Stern was the only member of the panel to vote against lowering the standards.