For overweight people with heart disease, trying and failing to lose weight may be more dangerous than not losing weight at all.
A new retrospective study has concluded that patients whose weight fluctuates the most die twice as quickly or have twice the risk of heart attack or stroke compared to people who maintain a stable body weight.
And their risk of developing diabetes grows by 78 percent.
The findings, which need to be confirmed by further research, suggest a life-and-death conundrum. Being overweight is already known to pose serious health risks. The new research says dropping the pounds and putting them back on again poses additional dangers.
If you are an overweight person with heart disease who lost 20 pounds "you are worse off if you drop your weight and gain it back" than if you didn't lose it in the first place, chief author Dr. Sripal Bangalore, an interventional cardiologist and associate professor of medicine at New York University's Langone Medical Center told Reuters Health by phone.
The study is saying, "If you're going to lose weight, do it right and you need to take it seriously," said Dr. Ira Ockene, a professor of medicine at the University of Massachusetts Medical School in Worcester, who was not connected with the research.
If people use the results as an excuse not to drop unhealthy pounds, "that would be unfortunate," Ockene told Reuters Health. "There's a lot of data that says if you lose weight and keep it off, you do better."
"Hopefully this will be used as a motivation to lose weight and maintain weight," Bangalore said.
Such yo-yo dieting, where a person's weight fluctuates repeatedly, is already known to be unhealthy in people without heart disease.
The new study in the New England Journal of Medicine explored whether that was specifically true for people with coronary artery disease, where fatty deposits have built up in the blood vessels feeding the heart muscle. The researchers recycled data from 9,509 volunteers who were part of a Lipitor study published in 2005 and sponsored by Pfizer.
Another important limitation of the study: It did not examine whether patients lost weight because they tried to, or if their weight fluctuated because they were battling illness.
After adjusting for various factors such as high blood pressure, smoking, race, gender, diabetes, cholesterol levels and treatment with Lipitor, the Bangalore team found that people whose weights fluctuated the most were 2.24 times more likely to die from any cause within about five years, 2.17 times more likely to have a heart attack and 2.36 times more likely to be hit with a stroke than people whose weights were the most stable.
For every 3- or 4-pound change in body weight, their risk of heart attack, cardiac arrest, chest pain, death from heart disease or the need for surgery to open a clogged artery rose by 4 percent.
The dangers posed by shifting weight were least pronounced in people who had a normal weight to begin with.
Ockene said people need to put weight loss in perspective.
"Studies show people set unattainable goals. Heavy people say, 'I need to lose 40 pounds' and they set a goal that is largely unattainable. And when they lose 10 pounds they're disappointed. And they say, 'What the hell' and they just gain it back," he said.
"But if you lose 10 pounds and keep it off, your diabetes will be better, your blood pressure will be better, your lipids will be better, a lot of things will be better. You don't need to lose 30 or 40 pounds," he said. "That's an important issue for people to understand."
As a typical example of patients in the study whose weights fluctuated significantly, the researchers cited the case of a 53-year-old man whose weight went from 231 pounds to 244 pounds three months later, then dropped to 211 pounds eighteen months later before going up to 253 pounds after another 18 months had passed.