(CNN)Yo-yo dieting may increase the risk for coronary heart disease and sudden cardiac death in post-menopausal women, according to a study presented to the American Heart Association on Tuesday.
Although previous research focused on the heart risks associated with obesity, study leader Dr. Somwail Rasla of Memorial Hospital of Rhode Island questioned whether women with normal weights could be putting their hearts in danger by on-and-off dieting.
"Under normal conditions, we shouldn't be putting on or losing weight," Miller continued.
"If someone is a normal weight, keep it stable," Rasla agreed.
If a patient wants to lose some weight, Miller warns not to lose more than a pound a week. Instead of restricting food, he suggests eating a healthy diet and increasing energy output, or physical exercise, by about 300 calories a day.
Dr. Naveed Sattar, a professor of metabolic medicine at the University of Glasgow who wasn't involved in the study, emphasizes that weight loss is still a healthy choice for many people.
"This study does not change the fact that overall evidence shows the value of intentional weight loss where lifestyle changes lead to beneficial weight change," Sattar said. "If we look beyond this study at the totality of evidence, it shows us that if women (or men) try to lose weight intentionally, then there is no evidence from trials that this does anything other than good, even if weight gain recurs."
Dr. Suzanne Steinbaum, director of Women's Heart Health at Lenox Hill Hospital and a Heart Association spokeswoman, says the study "shows the real, true negative effects of what yo-yo dieting can do on our hearts, and this is very, very relevant and important for us to see and understand." Steinbaum was not involved in the research.
However, she continued, "I don't know how much emphasis we can put on this study, because it is an observational study" and is therefore not conclusive about the effects of yo-yo dieting.
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"In observational studies, there are always factors that can't be adjusted for," such as pre-existing unhealthy habits, Miller said. These outside factors may have triggered the women's heart conditions, he explained.
"This study has limitations," Sattar agreed. "Women of normal weight are less likely to be intentionally losing weight than overweight women, so this weight loss in normal weight women is much more likely to be unintentional and could be due to illnesses, and the study cannot rule that out. So, weight cycling in normal weight women may be disguising some underlying illness, and these same illnesses may also in turn increase heart disease risks."
Rasla also noted that the data collected for the study were self-reported, and the participants could have given biased answers. For future studies, he hopes to see participants' weights monitored for better precision.
Miller is hopeful about the study results and future research on yo-yo dieting's effects on heart health. "I think it's a great start," he said.