Study Links Fluctuations in Weight to Heart Disease : Health: Research suggests that dieters who repeatedly lose and then regain pounds are adding to the risk of dying from cardiac problems.

Yo-yo dieters who go through life taking off weight and putting it back on appear to significantly increase their risk of dying from heart disease, a study concludes.

Being overweight clearly raises the chances of heart trouble, but the new research suggests that repeated weight swings might be just as bad.

“People should take dieting seriously,” said Kelly D. Brownell, a psychologist at Yale University who was senior author of the study. “They should try to ensure that chances of success are high before they begin.”

The study found that the risk of dying from heart disease is about 70% higher in those with fluctuating weight than in those whose weight stays reasonably steady.

Results of the study were published in today’s New England Journal of Medicine.

Dr. George Blackburn, a diet expert at New England Deaconess Hospital, said he will ask the National Institutes of Health to reconsider recommendations that everyone achieve ideal body weights, even when they are obese.

“The Brownell data are enough for us to say, ‘Let’s not do any radical dieting until we sort this out, because we might be worse off than if we did nothing at all,’ ” he said.

Blackburn said people should be especially careful about trying to lose more than 25 pounds or 10% of their body weight.

“Don’t panic if you’ve lost 25 pounds and put it back on,” he said. “But if you’ve done it twice, you shouldn’t do any more in this area without professional help.”

The potential dangers of up-and-down weight have become a subject of concern over the past few years. Until now, however, doctors have warned against the habit largely because of the risk that dieters will put back on more pounds than they take off.

Brownell’s study raises the possibility that they might also heighten their risk of heart disease, the nation’s No. 1 killer.