Obesity is becoming increasingly widespread in the United States, and so are a variety of dieting options. Many people who lose weight, however, quickly regain it. New research suggests that rapidly and repeatedly losing and regaining weight may increase the risk of death from heart disease.

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Weight cycling may be dangerous for your heart, new study suggests.

Obesity increases the risk for some of the leading causes of death in the United States, such as heart disease, stroke, diabetes, and some forms of cancer. Being obese or overweight is also linked to an overall lower quality of life and poorer mental health.

The Centers for Disease Control and Prevention (CDC) report that more than one third of Americans are obese, but efforts to lose weight are also significant.

Twenty-four percent of American men and 38 percent of American women have reportedly been trying to lose weight, and the number of obese individuals who are trying to lose weight is five times higher than those of a normal weight.

While some of these people lose weight quite quickly, they may be just as quick to regain it. This is popularly referred to as “weight cycling” or “the yo-yo effect.”

A previous study reported that 7 percent of men and 10 percent of women can be classified as severe weight cyclers, defined as deliberately losing a minimum of 5 kilograms and regaining it at least three different times.

New research suggests yo-yo dieting can be bad for your health; it may have negative effects on your heart, even if you are not overweight.

A new study presented at the American Heart Association’s Scientific Sessions 2016 suggests yo-yo dieting may increase the risk of death from heart disease among older women of normal weight.

Although some rat studies have suggested that weight cycling disrupts metabolism and normal physiology, the effects of rapid weight regain have so far been unclear.

Fast facts about heart disease
  • About 610,000 Americans die yearly of heart disease. That is 1 in 4 deaths every year
  • Coronary heart disease is the most widespread type of heart disease, accounting for 370,000 deaths every year
  • About 735,000 people in the United States have a heart attack every year.

Learn more about heart disease

“Weight cycling is an emerging global health concern associated with attempts of weight loss, but there have been inconsistent results about the health hazards for those who experience weight cycling behavior,” says lead author Dr. Somwail Rasla, of the Memorial Hospital of Rhode Island.

For the study, Dr. Rasla and team divided 158,063 postmenopausal women into four categories: stable weight, steady gain, maintained weight loss, and weight cycling.

They followed up on the participants for 11.4 years and found that women who had a normal weight at the beginning of the study but then lost and regained weight had a much higher risk of sudden cardiac death, compared with women who kept a stable weight throughout the period.

In fact, women of normal weight who subsequently experienced the yo-yo effect were 3.5 times more likely to die from sudden cardiac arrest than women whose weight remained stable.

Women considered overweight or obese at the start of the study, and who experienced weight cycling, presented no increase in any kind of heart disease-related death.

No increase in death was reported by women who gained weight but did not lose it, nor women who lost weight but did not gain it back.

Evidence in this study suggests that being overweight in midlife increases the risk of death from two types of heart disease: coronary heart disease and sudden cardiac death.

In coronary heart disease, fat and other substances gradually block the blood vessels and stop the blood flow from reaching the heart. In sudden cardiac death, the heart’s electrical system to the heart suddenly malfunctions and causes death.

The researchers note some of the limitations of their study.

Firstly, the research is just observational, meaning that it only shows an association between weight cycling and heart problems, but it does not establish a causal relationship. Further research would be needed to explain the mechanism behind the association.

The study also relied on self-reporting, which always runs the risk of being inaccurate.

Finally, the cases of cardiac death were relatively infrequent and the study included older women, so a wider-sized demographic would be needed to clarify the risks of weight cycling.

“More research is needed before any recommendations can be made for clinical care regarding the risks of weight cycling, since these results apply only to postmenopausal women and not to younger-aged women or men,” Dr. Rasla says.

Until more research backs specific recommendations for yo-yo dieting, the American Heart Association remind us of the seven steps for reducing the risk of heart disease: manage your blood pressure, control your cholesterol, limit sugar intake, get active, eat a healthy diet, keep a normal weight, and stop smoking.

Learn about how a high-protein diet may raise heart failure risk for older women.