©REUTERS/Lucy Nicholson
A hamburger is displayed in Hollywood, California October 3, 2007.

Eating a high-fat, high-carb fast food meal produces damaging cellular changes that are greater and longer-lasting in obese people than in normal-weight people, a new study shows.

Dr. Paresh Dandona and colleagues from Kaleida Health in Buffalo, New York looked at inflammation and oxidative stress, which occurs when levels of normal byproducts of metabolism known as free radicals exceed the body's ability to neutralize them.

In previous research they found that obese individuals have higher levels of oxidative stress and inflammation than normal-weight individuals. They also demonstrated that eating a high-fat, high-carb meal increased oxidative stress and inflammation in normal-weight people.

To test whether these increases might be greater in obese people, Dandona and his team had 10 normal-weight and 8 obese people eat a 1,800-calorie meal consisting of a large hamburger, a large serving of fries, a large cola, and a slice of apple pie.

Both groups showed increases in oxidative stress two hours after eating the meal. By three hours, oxidative stress had returned to baseline levels in the normal-weight individuals, but it continued to climb in the obese individuals. The same pattern was seen for inflammation.

"If obese people who already have oxidative and inflammatory stress take the same meal, they get far greater and more prolonged levels of oxidative and inflammatory stress," Dandona told Reuters Health. "Since oxidative and inflammatory stress predispose you to atherosclerosis (hardening of the arteries), heart attack and stroke, this risk is far greater in obese people."

In another study, Dandona and his colleagues demonstrated that a high-fruit, high-fiber meal with the same calorie content as the fast food meal tested in the current study produced no increase in oxidative or inflammatory stress.

The findings provide yet more evidence that people should avoid high-fat, high carb fast food meals and consume as much fruit and vegetables as possible, Dandona said.

SOURCE: The Journal of Clinical Endocrinology & Metabolism, November