We tend to blame the obesity epidemic in the United States on people making the wrong lifestyle choices -- for example, eating a Big Mac instead of carrot sticks or Twinkies instead of an apple.
New research shows, however, that the price of healthy food may be too high for many low-income families to afford, and experts say the government needs to step in.
A new study published in the journal of the American Dietetic Association finds that a low-income family would have to devote 43 to 70 percent of its food budget to fruits and vegetables to meet the 2005 Dietary Guidelines, which recommends five to nine servings of fruits and vegetables a day.
"Most Americans fall short of the recommended servings," says Milton Stokes, a registered dietitian and a spokesman for the American Dietetic Association.
"The lower their economic status, the more of their income is spent toward food," he says. "Someone making $20,000 is going to spend a larger percentage of dollars on food than someone making $200,000, even if they buy the same amount."
Currently, researchers say that American families spend 15 to 18 percent of their budget on fruits and vegetables.
"It seems unlikely that consumers would be able to increase their spending on fruits and vegetables by 200 percent to 400 percent without substantial changes elsewhere in the food budget, or from other household expenditures," the authors of the report note. "For low-income consumers this may be especially challenging, because there are few discretionary funds available in these other accounts."
Fruits and vegetables tend to be more expensive than processed foods for a number of reasons.
Fresh produce has a short shelf life, which means that it spoils and therefore can't be bought in bulk and stored in the same way processed or preserved foods can.
Fruits and veggies also lack the backing of government subsidies, such as those for products like high fructose corn syrup, and they can't be mass produced in an automated assembly line. We just have to wait for nature to ripen the apples.
However, reducing the price of fruits and vegetables will not necessarily cause people to eat them more often. Dr. David Katz, director of the Prevention Research Center at the Yale University School of Medicine, explains how the problem is cultural as well as financial.
"If you took the price of fruits and vegetables down by 10 percent, consumption would not increase," he says. "There are barriers that go beyond the issue of price. For example, if you pay for health insurance, it doesn't mean that health care improves.
"The same holds true with fruit consumption. If the cost of fruits and vegetables is cut in half, you are still going to have people who aren't used to eating them and who don't know how to incorporate them into their diets. Habits have to change. Reducing the financial barrier is only the first step."
And even if people are able to afford produce, a bag of carrots isn't going to fill you up the way a Snickers bar does.
"The major concern for low-income groups is not to be hungry at night," says Adam Drewnowski, director of the Center for Obesity Research at the University of Washington in Seattle. "They gravitate to foods that fill them up -- foods that are high in fat and sugar. For them, vitamins and minerals are a luxury."
Furthermore, availability can also present a problem for low-income families.
"The neighborhood you live in affects consumption because supermarkets in low-income neighborhoods may have less-appealing produce, so people are less likely to buy it, or people may shop at a bodega instead of a supermarket where produce is less available," says Katz.
Experts say that the problem can be solved only by eliminating financial barriers, creating incentives to buy healthy foods, and cultivating changes in peoples' attitudes.
"One idea is to place a small tax on foods with low nutritional value, like soda, for example, and to use the revenue collected to subsidize fruits and vegetables," says Katz. "A tax on low nutritional foods could be the funding source to subsidize foods with a higher nutritional value."
Another solution might be to link the purchasing power of food stamps to the nutritional quality of the food.
"For example, if people are buying junk food, a $1 food stamp is worth $1 of food," Katz explains. "But that same $1 could be worth $2 if people are purchasing fruits and vegetables."
Drewnowski believes that the government needs to play a larger role in subsidizing fruits and vegetables.
"This problem no longer lies with individuals," he says. "There needs to be a concerted government initiated policy to deal with the issue."
In addition to a larger governmental role, the authors believe education is necessary.
"There is a need to educate consumers about the importance of increasing their consumption of fruits and vegetables, yet these education programs must consider the tradeoffs required for families to purchase more fruits and vegetables," the authors say. "Education on household budgeting and follow-up with consumers may be needed as people work to change spending habits to eat more healthfully," they write.
In the long run, paying more for fruits and vegetables now holds long-term savings for both families and the government in the future. The reason experts recommend so many servings of fruits and vegetables is that they offer the best way to prevent chronic diseases such as diabetes and cancer.
"The more fruits and vegetables you include in your diet, the lower your risk for all the major chronic health problems, such as heart disease, diabetes, many cancers, high blood pressure, the list goes on," says Keith-Thomas Ayoob, associate professor of pediatrics at the Albert Einstein College of Medicine in New York.
"I think of it as spending $65 every two weeks to help prevent a family of four from getting cancer, heart disease and diabetes. That's cheap prevention. No medication can do that so this is money that is well spent."
"Both food stamps and health insurance for the poor are government subsidized programs," he says. "The government is paying people to eat poorly and then is paying to deal with the health consequences.
"It would be more economical to pay people to eat well so that you don't have to treat them in the hospital when they have heart disease and diabetes."