Two reports released this summer on the prevalence of obesity among Americans had encouraging news, but also showed that there's still much work to be done to trim America's waistline. The Centers for Disease Control and Prevention (CDC) reported that after decades of upsurge, obesity rates among low-income preschoolers have slowed. Between 2003 and 2008, they held steady, and from 2008 through 2011, they declined, albeit modestly, in 19 of 43 states and U.S. territories studied. This still means, however, that one in eight U.S. preschoolers is obese. (See the full CDC report at http://1.usa.gov/14ngmBD.)

Figure. First Lady Michelle Obama sings and dances with staff, parents, and children, as part of her Let's Move! initiative, at the Royal Castle Child Development Center in New Orleans, Louisiana. Photo by Gerald Herbert / Associated Press.

In its annual F as in Fat report (http://bit.ly/1aTLgLh), the Robert Wood Johnson Foundation and the Trust for America's Health noted similar progress: after three decades of increases, adult obesity rates stayed level in 2012 in every state except Arkansas. The report hastened to note that the rates remain very high, with more than two-thirds (68.7%) of the adult population being either overweight or obese.

The report's demographics revealed that, whereas a decade ago the obesity rate in women was higher than in men (33.4% and 27.5%, respectively), the rates today are practically indistinguishable (35.5% and 35.8%). And although obesity rates didn't vary much among male racial and ethnic groups (36.2% in white men, 38.8% in black men, and 36.6% in Mexican American men), they varied significantly among women (32.2% in white women, 58.5% in black women, and 44.9% in Mexican American women).

The authors of F as in Fat write that the success in stopping the increase in the obesity rate among children demonstrates that the United States must act to prevent obesity in all citizens and develop "a truly comprehensive approach" that changes "public policies, community environments, and industry practices in ways that support and promote healthy eating and physical activity." The CDC report, too, has a prescription: physicians and nurses must routinely measure children's weight and height, calculate every child's body mass index, and counsel parents on nutrition and the importance of physical activity.-David Carter