Houston. Why - because:
More than 23% of Houstonians are clinically obese (per CDC) and almost 62% are overweight. In Texas - More than 1 out of 4 adults is clinically obese and almost 3 out of 10 haven't been physically active at all for the past 30 days.
Houston's TV-watching rate is the third-highest (per Nielsen Media Research data).
In a measure of doughnut shops per capita, Houston boasts more than twice the national average.
Houston's EPA air quality rating is worse than any other city in our survey except Philadelphia and Fresno, with which it tied for last place.
Others in the top ten: Philadelphia, Detroit, Memphis, Chicago, Dallas, New Orleans, New York, Las Vegas and San Antonio.
Top fittest: Seattle, Honolulu, Colorado Springs, San Francisco, Denver, Portland, Sacramento, Tucson, San Diego, Albuquerque - Boston 11th.
http://www.mensfitness.com/rankings/304 or
http://www.usatoday.com/news/health/2003-01-01-cities-usat_x.htm