The introduction of more than 5,000 low-fat and non-fat foods over the past decade has contributed to an epidemic of obesity in America, the American Heart Association (AHA).

The trouble comes when people think they can eat unlimited amounts of reduced-fat cookies, frozen yogurt and cakes. While these foods contain less fat than their full-fat versions, they tend to have more sugar and can be even higher in calories.

Choosing fresh produce and other fiber-rich foods allows a person to eat a large volume for relatively few calories because it promotes a feeling of fullness.

The advice from health experts comes at a time when rates of obesity are unprecedented in the US and other countries. While Americans have followed the government's advice and reduced fat intake in the past half-century, they continue to pack on the pounds.

Studies have shown that the rate of obesity has doubled in the US in the last 20 years while the number of people with type 2 diabetes, a disease that can result from excess weight, increased by one-third during the 1990s. Children as young as 10 are now being diagnosed with type 2 diabetes, formerly known as adult-onset diabetes because it affected people in their 40s and older.

The AHA's statement recommends that individuals who want to lose weight and maintain a healthy body weight follow the US government's food guide pyramid and pay particular attention to portion sizes. A serving of meat, for instance, is just 3 ounces or roughly the size of a deck of cards. A half-cup of pasta is equivalent to a serving of carbohydrate.

Circulation June 11, 2002;10.1161/01