A new study has found that yo-yo dieting or on-and-off dieting could be harmful to the heart. And the risk is more evident among women with normal weights.

According to a new research presented at the American Heart Association's Scientific Sessions, yo-yo dieting -- a practice wherein a person loses weight quickly and then regains weight by eating as much as he/she used to -- could increase the risk of coronary heart disease in post-menopausal women.

"We found that those with normal weight were the highest at risk for both sudden cardiac death and coronary heart disease death," Dr. Somwail Rasla, internal medicine resident at Memorial Hospital of Rhode Island at Brown University and study author, said in a statement.

The research team analyzed data from158,000 women over the age of 50 categorized as normal weight, overweight or obese. The women also reported their adult weight histories - whether they were maintaining a stable weight, steadily gaining weight, steadily losing weight or weight cycling (lost and regained 10 pounds or more). The women were followed for 11 years, recording sudden cardiac deaths and deaths due to coronary heart disease.

Over the course of the study, the researchers tallied 2,526 coronary heart disease deaths and 83 sudden cardiac deaths. They found that women who had normal weight during the start of the study but who reported a history of weight cycling more than four times were 3.5 times more likely to have sudden cardiac death than those with stable weights. They also had a 66 percent increased risk of coronary heart disease deaths.

The frequency of weight cycling also adds to the risk. The more a person does it, the more it becomes hazardous to his/her heart, Rasla said.

According to Rasla, yo-yo dieting could lead to fluctuations in risk variables like heart rate, blood pressure, cholesterol and blood glucose. It could also lead to insulin resistance, which increases the risk of coronary heart disease death.

In the United States alone, 20 to 50 percent of the female population is weight cycling, compared to only 10 percent to 20 percent of men, CNN reports.