How yo-yo dieting impacts women's heart health

By Ana Sandoiu 

Fact checked by Isabel Godfrey

New research reveals worrying associations between yo-yo dieting and seven well-established markers of cardiovascular health.

As if losing weight wasn't hard enough, up to 80 percent of people who manage to lose more than 10 percent of their body weight end up regaining the weight within a year.

Losing weight for a short period and then regaining it bears the name of yo-yo dieting, which some people refer to as "weight cycling."

Previous research has pointed out the potentially damaging effects of these repeated cycles of weight loss and weight gain.

Some studies have suggested that yo-yo dieting raises the risk of mortality from any cause, while others have pointed to an increased risk of death from heart disease in particular.

Another study suggested that yo-yo dieting can lead to a cardiometabolic "roller coaster" in which cardiovascular health remarkably improves with just a few weeks of healthful dieting, but the negative cardiovascular effects are immediate once the individual abandons the diet.

Now, scientists have turned their attention to the cardiovascular effects of yo-yo dieting in women.

Dr. Brooke Aggarwal, who is an assistant professor of medical sciences at Columbia University Vagelos College of Physicians and Surgeons in New York, led a team examining the effects of weight cycling on seven heart disease risk factors.

Dr. Aggarwal and her colleagues presented their findings at the American Heart Association's (AHA) Epidemiology and Prevention | Lifestyle and Cardiometabolic Health 2019 Scientific Sessions, which took place in Houston, TX.

Yo-yo dieting and optimal heart health

The researchers examined 485 women who had an average age of 37 years and a median body mass index (BMI) of 26.

The study participants reported how often in their lives they had lost at least 10 pounds and then regained the weight within a year.

The researchers assessed the women's health using "Life's Simple 7" — the risk factors that the AHA use to define ideal cardiovascular health.

"Life's Simple 7" uses seven modifiable risk factors to measure a person's heart health. These factors are: "smoking status, physical activity, weight, diet, blood glucose, cholesterol, and blood pressure."

Overall, 73 percent of the women in the study said that they had experienced at least one episode of weight cycling. These women were 82 percent less likely to have a healthy BMI, which the medical community defines as being between 18.5 and 25, than the women who had not had any episodes of yo-yo weight loss.

These women were also 65 percent less likely to fall within the "optimal" range of "Life's Simple 7." The AHA note that people in the optimal range have a much lower risk of heart disease and stroke than those who fall in the "poor" ranges.

In the current study, the negative effects of yo-yo dieting were more noticeable in the women who had never been pregnant.

"The women without a pregnancy history were likely younger and might be those who started weight cycling at an earlier age," explains Dr. Aggarwal.

"We need to identify critical periods for the effect of weight fluctuation on heart disease risk over the life course to find out whether it is worse when women start on a dieting roller coaster at an early age," she continues.

However, the senior author emphasizes that the study cannot establish causality. The team was unable to determine whether yo-yo dieting negatively affects a person's ability to adhere to "Life's Simple 7" or whether the reverse is true.

"We hope to extend the study 5 to 10 years to confirm these results and look at long-term effects," Dr. Aggarwal says.

Although the current findings are not generalizable to men, "there has been prior research that showed similar results in men, with those who weight cycled having twice the risk of cardiovascular death in middle age," the author explains.

SOURCE: MEDICAL NEWS TODAY