We all know that obesity rates are increasing in the United States, but nobody wants their city to be known as the nation's fattest.

FAT/FIT CITIES 10 Fattest Cities 10 Fittest Cities

But Men's Fitness editors released their fifth annual "America's Fattest Cities" rankings, finding that Houston takes the cake in the fattest city competition.

Texas cleaned up its act somewhat this year, with two cities dropping out of the top 10, but Houston retained its title as "America's Fattest City" for the third year running.

Other cities near the top of the list included Chicago, Detroit and Philadelphia.

As far as fittest cities go, Honolulu climbed to the top of the list after coming in at No. 7 last year. Other healthy cities on the list included Seattle, San Francisco, Colorado Springs, Colo., and San Diego.

The magazine evaluated the nation's 50 largest cities between July 2002 and September 2002. Cities were assessed in 16 categories, including fruit and vegetable consumption, sports participation, smoking, drinking, air and water quality, length of commute, availability of parks/open spaces, and percentage of overweight/sedentary residents.

Roughly one out of three Americans is now obese, and if you factor in those who are overweight, nearly every two of three Americans has a serious weight problem, according to the National Health and Nutritional Survey, reported in the Journal of the American Medical Association in October 2002.

"The increases are across the board for all age groups, both sexes and in all races," said Cynthia Ogden, co-author of the study.

"If these rates continue -- about 1 percent gain per year -- we'll all be overweight by the year 2035 and obese by 2100," said John Foreyt, director of the Nutrition Research Clinic at Houston's Baylor College.

Men's Fitness editors also point out the financial impact obesity has on the nation's health care system. The article says $120 billion is spent annually treating the results of this epidemic of obesity.

The editors said exercise is crucial to lowering people's weight. People tend to blame fast foods, snack foods and round-the-clock consumption for the epidemic, but many experts are convinced that people simply need to exercise more.

"Even moderate exercise, without breaking a sweat, is enough to start reversing the trend," said Jim Hill, director of the Center for Human Nutrition at the University of Colorado.

The editors also said that communities need to rally to overturn citizens' health problems.

"We're finally waking up to the seriousness of it," Foreyt said. "What's needed now is action starting at the local level."

Real effort and funding need to be put into education, public health, parks and recreation, pedestrian-friendly development, and exercise and nutrition initiatives, he added.