If you're carrying around a few extra pounds, you can spread the blame like butter. Partially at fault is a modern society that values cars more than walking. Today's workers are more likely to use a keyboard than wield an ax. Suburban sprawl has turned us into a nation of 25-minute commuters. And fear of crime is making us keep our children close so they don't do much walking either.

How you feel about your automobile and your neighborhood have a lot to do with your weight, suggest recent studies.

"Obesity is a public health crisis. If the rate of obesity and overweight continues at this pace, by 2015, 75 percent of adults and nearly 24 percent of U.S. children and adolescents will be overweight or obese," said Dr. Youfa Wang, who led the study, in a press release.

Worse, there are patterns for obesity. At high risk are black women over age 40, fifty percent of whom were obese in 2004, according to body mass index definitions. In addition, less educated families are more likely to become obese.

It's a sad thing that children are being drawn into a culture where they're at greater risk for a host of illnesses from diabetes to heart trouble. In fact, overweight and obesity will soon be the leading preventable cause of death in the U.S., more than smoking.

The simple reason is most of us are taking in more calories than we're burning, and we can blame our automobile-loving culture for more than gas gluttony. We can blame it for food gluttony, too.

In an article for the American Journal of Preventive Medicine, fewer than half of American children who live close to their schools walk or ride bikes to class, found the U.S. Centers for Disease Control.

That's a big change from 1969 when about 90 percent of kids used their feet or bikes to get to their neighborhood schools.

Researchers speculate that safety concerns are the reason parents drive their children to school, rather than let them walk or bike, and the more cars the family owns, the more likely the kids are to be driven to school. Some communities have reflected the decades-long enchantment with cars by eliminating pedestrian-friendly safety measures, the experts noted, lacking continuous sidewalks or safe crosswalks.

But unwalkable neighborhoods aren't just a suburban problem. Urbanites are in love with cars, too.

In Dallas, Texas, the banking center for the Texas oil industry, public transportation has been a relatively recent and tough sell. Dallas expanded its light rail exponentially. In 2002, light rail routes increased from 20 to 44 miles, but in the same period, ridership dropped nearly 9 percent. Meanwhile, from 2001 to 2003, roadway use increased 3.1 percent in the Dallas-Fort Worth urban area.

But it's no better in more experienced cities like San Francisco, where the number of people who drive alone in the city has increased from 33.8 percent in 1980 to 40.5 percent in 2000. and those using public transit has dropped to 31.1 percent in 2000 from 38.5 percent in 1980.

In fact, the use of public transportation has declined 60.8 percent since 1960, and walking to work has declined by 70.5 percent, according to figures compiled by Publicpurpose.com .

In a research finding on active living for the Health Promotion Journal, 865 adults in 11 major metropolitan areas participated and demonstrated that their "decisions to walk for travel are more influenced by our attachment to private automobiles, than by the qualities of surrounding neighborhoods," said the report. "We are reminded from these results that built environment changes to support active living must be accompanied by attitude changes. Living in activity-supportive environments will not guarantee a shift in travel mode choice for many individuals."