Excessively overweight teenagers face a slew of heart disease–causing conditions, such as inflammation, insulin resistance and metabolic system problems, because of bad diet and lifestyle choices, according to a study presented at the American Heart Association scientific sessions in Atlanta and reported by HealthDay.

For the study, researchers compared the diets of 33 obese teens, ages 11 to 19, to 19 normal weight people in the same age group. (Researchers determined participants’ weight category using their body mass index, a ratio of height to weight.) In addition, scientists also examined each participant’s blood test results.

According to the findings, obese teens showed signs of inflammation, insulin resistance (a precursor to diabetes) and oxidative stress (which can lead to blood vessel damage).

“The metabolic abnormalities suggest that the process of developing heart disease has already started in these children, making it critical for them to make definitive lifestyle and diet changes,” said senior study author Ashutosh Lal, MD.

While researchers noted that both groups of teens struggled with maintaining a healthy diet, obese teens in particular ate less dairy and fewer servings of fruit. In particular, obese teens’ diet lacked potassium and vitamins A, C and D, found in fortified dairy products and deeply colored fruits and veggies.

Explained Lal, “For their heart health, obese teens need to eat better, not just eat less.”

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