Despite all the warnings, many Americans continue to be overweight or obese. The numbers are alarming.
One contributor to the obesity epidemic is fast food. But not everyone who eats it gets fat. Researchers took a look at the reason why.
Sixteen year old Tara Searight eats fast food about once a week. She especially loves fries.
Tara Searight: "Every time I eat fast food I keep thinking this is awful for me. I know this is awful for me and I just can't stop because it tastes so good."
Tara is not unique. Three out of four teens eat fast food at least once a week.
New research zeroed in on why some of these teens will remain lean while others gain weight.
American researchers measured how many calories teens consume during a large fast food meal. Then they tracked how many other calories were consumed during the day when teens ate fast food, compared to days when teens did not.
Researchers found that after a fast food meal, lean teens ate fewer calories the rest of the day.
Cara Ebbeling, Ph.D./ Children's Hospital, Boston" "Obese adolescents had a particular problem compensating for the calories in a large fast food meal, such that they consumed 400 more calories on days when they had a fast food meal compared to days when they did not."
The study found that during a single large fast food meal, teens consumed sixty percent of their daily calorie needs.
Lean teens like Tara are more aware, and compensate for the rest of the day.
Tara: "If I have fast food for lunch, I'll definitely try to have something healthier for dinner like a salad, or put in some extra fruits and vegetables."
Researchers say they don't know if teens lose the ability to compensate for eating all those calories once they become obese.
There is no question though, that all teens, and all of us, should eat less fast food.