Most people know that get-thin-quick diets don’t work and just lead to a cycle of weight gain and loss. But these schemes are not only ineffective — yo-yo dieting can raise the risk of dangerous health problems for people with coronary disease.

For a study published today in the New England Journal of Medicine, researchers looked at data from almost 10,000 men and women with coronary artery disease. All of the participants were between 35 and 75 and half were taking a drug to lower cholesterol.

Over the four years they were monitored, people who repeatedly gained and lost weight were more likely to have an entire slew of health problems. The group with the biggest weight changes had 124 percent more deaths than those whose weight remained the most stable. In addition, they had 117 percent more heart attacks and 136 percent more strokes.

It’s important to note it’s not clear that weight cycling actually causes the bad outcomes. Also, because they were looking at preexisting data from a different study, the researchers people didn’t know whether the subjects lost weight because they were sick or dieting or for any other reasons. That said, more than a third of Americans are obese, according to the Centers for Disease Control and Prevention, and half of them are trying to lose weight at any time. Because obesity itself puts people at risk for heart disease, it’s not uncommon for those with heart disease to be overweight.

Perhaps the most sobering thing about this study is that people in the “high-fluctuation” weight group didn’t even see the numbers budget that much, usually only about nine pounds. In contrast, to be in the group with the smallest shift in weight, your weight had to be almost entirely stable, changing by only about two pounds.