Yo-yo Dieting Could Damage Women's Heart Health

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Yo-yo dieting has been linked to an increased risk of heart disease in a study. Getty Images

Women who yo-yo diet risk their damaging their heart health, scientists have warned.

Researchers arrived at their conclusion after carrying out a cross-sectional study on 485 women who took part in a research program for the American Heart Association.

At any given time, almost half of the U.S. population is trying to lose weight. That goal is most common among women, Dr. Brooke Aggarwal, senior author of the study and assistant professor of medical sciences at Columbia University Vagelos College of Physicians and Surgeons in New York, told Newsweek.

"We chose to study women in particular because women are more likely than men to engage in dieting behaviors, and they are more susceptible to fat accumulation during certain time periods, such as pregnancy and menopause, and therefore may be at more at risk for weight cycling," she explained.

The researchers wanted to learn whether a history of yo-yo dieting, or weight cycling, affected a woman's heart health, and whether if she had been pregnant or was post-menopausal made a difference.

Weight cycling was defined as losing and gaining at least 10lbs at least once, excluding during pregnancy. The participants were scored according to the American Heart Association's Life's Simple 7 test, which calculates cardiovascular health according to an individual's BMI, cholesterol and glucose levels, smoking habits and diet and exercise levels. The women were grouped according to whether they scored poorly, moderately or highly on the test.

The results revealed that most women had weight-cycled at least once, and some had done so as many as 20 times.

Those who had yo-yo dieted repeatedly were 51 percent less likely to have scored as moderate or high on the Life's Simple 7 test, with more episodes linked to poorer scores. They also found these women were 82 percent less likely to have the ideal BMI.

Women who had not been pregnant were among the worst scorers, the data suggested.

The findings were presented as a poster at the American Heart Association's Epidemiology and Prevention, Lifestyle and Cardiometabolic Health Scientific Sessions 2019, and therefore has not yet been peer reviewed as studies published in journals are.

Aggarwal explained: "Rapid weight loss may lead to an increased loss of lean mass relative to fat mass; compared to weight regain, which causes an increase in adipose tissue. This change in body composition is one mechanism through weight cycling may increase cardiovascular risk."

As with all studies, the research was limited by a number of factors. Aggarwal said. "This was a cross-sectional analysis, which limits the ability to establish temporality and draw conclusions regarding a causal relation between weight cycling and cardiovascular health. We also used self-reported data to assess weight cycling, which may be subject to recall bias, and the intention behind weight loss and regain is unknown."

However, she stressed that while jumping from diet to diet might be bad for the heart, being overweight or obese carries its own risks.

"The results of this study should not necessarily discourage anyone from trying to achieve a healthy body weight in accordance with national guidelines for the prevention of heart disease, but I do think that it suggests that making small, consistent changes that one can live with, to avoid weight regain, is the way to go," she said. Focusing on preventing weight gain rather than weight loss alone is a wise approach, she said.

Aggarwal advised those who need to shed pounds to aim for modest losses.

Commenting broadly on the potential negative effects of yo-yo dieting, Victoria Taylor, a senior dietitian at the British Heart Foundation charity who was not involved in the research, also highlighted that obesity is a major risk factor for heart and circulatory diseases, and pointed out many people struggle to stick to a healthy weight.

She told Newsweek: "While there are lots of different diet plans available and public opinions as to which are the most effective, the important thing is to make sure the changes you make can work for you in the long term and will fit around your lifestyle."

"Eating to reduce your risk of heart and circulatory disease isn't just about weight. A well-balanced diet with plenty of fruit and vegetables, fish, pulses and whole grains has benefits for a range of risk factors and should also be combined with other lifestyle changes such as increased physical activity, stopping smoking and cutting down on alcohol."

The study is the latest to warn of the potential harms of weight cycling. Last year, a study suggested those who yo-yo diet and also saw fluctuations in their blood pressure, glucose and cholesterol were more likely to suffer from heart attacks and strokes. The findings were published in the journal Circulation.

And the authors of a separate study in mice published in the journal Physiology & Behavior in June 2018 argued such cycles raise the risk of diabetes.

"This study demonstrates that yo-yo dieting is actually worse than no dieting at all," lead author Professor Michael Cowley, of Monash University, said at the time.