Yo-Yo Dieting Is Dangerous for Your Health

When you need to lose weight, it can be very tempting to try an extreme, quick-fix diet—even though you know there’s a good chance the results won’t stick. But here is a powerful reminder that a slow, steady approach to dropping unwanted pounds (and keeping them off) remains the healthiest way to manage weight: A recent study found that yo-yo dieting and other forms of back-and-forth weight fluctuations were linked to higher risk for stroke, heart attack, and early death in people with heart disease.

Previous research has found that so-called weight cycling may be harmful for other groups of people, such as postmenopausal women. (Other research has suggested that losing excess weight is always good for the heart, whether it’s gained back or not.) The new study, published in the New England Journal of Medicine, is the first to measure the effects of weight cycling on people with pre-existing coronary artery disease, or hardening of the arteries.

The new study looked at data from a clinical trial that included 9,509 men and women between the ages of 35 and 75, all of whom had been diagnosed with coronary artery disease and high cholesterol. The study participants were prescribed different doses of cholesterol medication, and the original trial was sponsored by Pfizer.

The participants were tracked for about five years and had their weight assessed every six months. In that time, researchers found, repeated shifts in body weight were associated with more cardiovascular problems, although the link was only significant in people who were obese or overweight at the beginning of the study. Yo-yo weight changes were also associated with more newly diagnosed cases of diabetes.

Overall, people with the largest average weight changes (as much as 8.6 pounds between check-ins) experienced 136% more strokes, 117% more heart attacks, and 124% more deaths during the study than those with the smallest shifts (just under 2 pounds) in weight. For every 1.5- to 2-pound change in weight fluctuation, the risk of any coronary or cardiovascular event increased by 4%, and the risk of death by 9%.

These numbers were surprising, says lead author Dr. Sripal Bangalore, director of the cardiovascular outcomes group at NYU Langone Medical Center. “We were expecting that there would be some relationship, but weren’t expecting it to be that strong,” he says.

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The study was not able to determine why people were gaining and losing weight—whether it was intentionally, unintentionally, or the result of an illness. And it was not able to confirm a cause-and-effect relationship between weight cycling and future heart problems.

But the findings do suggest that doctors should be concerned about weight fluctuations in people with heart disease—a group that’s already at high risk of heart attacks, strokes, and other dangerous complications.

“When cardiologists see obese patients with coronary artery disease, we routinely recommend that they lose weight,” Dr. Bangalore says. “But the irony of that is that we know patients don’t just lose weight—they often gain it back quickly. We know this adds significant stress on the body, so we need to figure out how we can prevent that.”

Bangalore says the message here should apply to anyone trying to lose weight, not just people with heart disease. “I often see patients trying to lose a ton of weight, and once they achieve it they try to relax and go back to their old habits,” he says. “Whatever you can do to reduce weight is important, but once you do all that hard work, it’s also important to try to keep it off.”

This type of yo-yo weight cycling may not cause immediate symptoms, Dr. Bangalore adds, so patients may not realize how dangerous it is. “But this study, and others, do suggest that it’s doing real harm,” he says.

This article originally appeared on Health.com