You've heard of "defining deviancy down." How about "defining fat up?" Changing the definition of "overweight" can instantly put millions of Americans in that category. Though nothing in that act changes the fundamentals of national health, it does contribute to a sense of panic--and further regulatory actions and nanny-state activity.
Writing for the Mackinac Center, Diane S. Katz a provides a reminder of the federal government's weight guidelines:
A variety of lifestyle factors contribute to our growing girth. But some of the increase can also be attributed to the broader definition of "overweight" adopted in 1998 by the National Institutes of Health. In one day, the combined number of overweight Americans ballooned 29 percent, from 68 million to 96 million
Katz mentions several factors leading to weight gain, including increased use of labor-saving devices and decreased smoking.