"Energy-dense foods rich in starch, sugar, or fat are the cheapest option for the consumer. As long as the healthier lean meats, fish, and fresh produce remain more expensive, obesity will continue to be a problem for the working poor," Drewnowski says.

Fat in America is an economic issue, he says. The highest rates of obesity and type 2 diabetes are found among groups with the highest poverty rates, and the least education. "We think of obesity as being predicted by genetics; believe me, it is also predicted by incomes and zip codes," says Drewnowski. There are many reasons why low-income families have less access to affordable healthy foods. Those reasons may involve food pricing and marketing, school and work schedules, or even transportation and access to the nearest grocery store.

However, Drewnowski says, a combination of nutrition education, cooking skills, and savvy use of food assistance programs may be the way to stem the obesity tide. Through its National Research Initiative Competitive Grants Program, the U.S. Department of Agriculture's Cooperative State Research Education and Extension Service recently awarded funds to address the issue of obesity, with an emphasis on vulnerable groups, including recipients of food assistance. One such grant was awarded jointly to the University of Washington, with Drewnowski as principal investigator, and the Cooperative Extension of the University of California, Davis, with Dr. Marilyn Townsend as lead researcher. The USDA's Human Nutrition Research Center at Davis will also participate in the project.

This multi-state project will explore the relationship between dietary energy density, diet costs, and actual food expenditures in two groups of participants: 120 middle-income men and women in Seattle and 120 low-income women from four California counties. Studies to be conducted in Seattle will develop a new tool to estimate individual diet costs, using local supermarket prices, California food prices and mean national food prices for some 400 foods, as estimated by the Economic Research Service of the USDA.

Trendy weight-loss diets can really slim down the pocketbook. As estimated by USA Today, the daily cost of the Atkins diet was double what the average American spends on food. The salmon-rich South Beach Diet was not far behind.

"Whereas obesity affects minorities and the poor, most of our suggested remedies are resolutely middle-class," says Drewnowski.

All study participants will provide data on shopping patterns, away from home foods, availability and accessibility of preferred foods, participation in food assistance programs, and potential financial and psychosocial barriers to dietary change. Questions on sensory acceptability and satisfaction with the diet will be based on those developed for the USDA's Thrifty Food Plan.

The study goal is to develop ways to offer individualized dietary advice that takes food preferences, usual eating habits, and financial limitations into account, Drewnowski says. A new computer model will be used to develop better diets at an affordable cost. The model will optimize nutrient density, maximize palatability, and minimize diet costs, without departing too far from usual eating habits. Helping low-income consumers obtain high-quality diets at an affordable cost may be the key strategy for stemming the obesity epidemic among the disadvantaged groups.

"We have enough information about which foods are healthy and which foods are not. But affordability and access -- that's a different story," said Drewnowski. "The focus on the cost of healthy diets will help us design better nutrition policies and programs."

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