What do food prices and childhood obesity have in common? The relationship is more mixed than you might think.

When researchers in Washington, DC analyzed food prices and their relationship to childhood obesity, they found that lower prices for fruits and vegetables and higher-priced soft drinks both helped keep children's weight in a healthier range.

The lack of affordable fruits and vegetables in a neighborhood is one factor that not only promotes obesity among children, but increases the risk of food insecurity as well. American University researchers used data from a national study of children from birth to age five together with information on local food prices.

Children in areas where fruits and vegetables were expensive had higher body mass indexes (BMI) than those in areas where fruits and vegetables cost less. The opposite was true among children in areas where the price of soft drinks was high: in those neighborhoods there was a lower likelihood of children being overweight.

Frozen fruits and vegetables are picked at their nutritional peak and then sent directly from the field to a nearby food processor. Because they are processed so quickly, they are nutritionally equivalent to their fresh counterparts.

“Results suggest that policies that subsidize the cost of fresh fruits and vegetables may be effective in improving the health and weight outcomes of young children,” the authors write.

SNAP, the Supplemental Nutrition Assistance Program, is testing incentives that reduce the cost of fruits and vegetables, including offering financial incentives for purchases at farmer’s markets.

There are healthy alternatives to fresh produce when the price of fresh fruits and vegetables can be out of the budget, such as during the cold winter months. Frozen and canned fruits and vegetables can be cost effective ways of including nutritionally-rich, healthy foods in family meals and snacks.

Frozen fruits and vegetables are picked at their nutritional peak and then sent directly from the field to a nearby food processor. Because they are processed so quickly, they are nutritionally equivalent to their fresh counterparts.

Canned foods lose some vitamins and minerals in the canning process, but not so much that they are not a good alternative when fresh produce is scarce or flown in from distant locations at great expense. The main drawback to canned vegetables is the salt added for preservation.

Rinsing canned foods before cooking will help to remove some of the salt. "No salt added" or "low sodium" canned vegetables are good choices, but usually cost more. Canned fruits should be packed in their own juice or in water, not syrup.

You can stretch your food dollars to include more fresh produce if you buy in season when prices are lower and can or freeze them yourself. In the dead of winter, when frozen or canned fruits and vegetables will likely be a better bargain at the store, watch for them to go on sale and stock up.

The study is published in Pediatrics