Yo-yo dieting, the practice of constantly gaining and losing weight of 10 pounds or more, has proven to increase chances of death due to heart disease in normal weight postmenopausal women, according to a new study.
Conducted by the Memorial Hospital of Rhode Island, the study examined the self-reported weight history of 158,063 postmenopausal women and followed it up 11.4 years later. The women were categorized into four groups: stable weight, steady gain, maintained weight loss and weight cycling (or yo-yo dieting).
Researchers found that the women who started the study at normal weight and fluctuated throughout the time period were three-and-a-half times more likely to die of sudden cardiac death than those whose weight remained stable. The high-risk women also displayed a 66 per cent increased threat of dying from coronary heart disease.
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By contrast, there was no heart risk associated with overweight or obese women who reported weight cycling. Similarly, neither stable weight gain nor stable weight loss were factors for concern.
Dr. Somwail Rasla, the study’s lead investigator, attributed weight cycling’s danger to the “overshoot theory.” In the case of yo-yo dieting, he said, weight gain increases cholesterol levels and body fat, and raises blood pressure. Those levels drop in the weight-loss phase, but not to a healthy baseline because the “normal state” was overshot in the weight-gain phase. The more gain-loss cycles a woman puts herself through, the more detriment she’s doing to her health, even if she appears to be a healthy weight.
In an interview with CNN.com, Dr. Suzanne Steinbaum, director of Women’s Heart Health at Lenox Hill Hospital and a Heart Association spokeswoman, said 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.”
This phenomenon is not gender-specific; Rasla reports that 10 to 20 per cent of American men admit to yo-yo dieting compared to 20 to 55 per cent of women.
However, he’s also quick to point out that this was an observational study where data was self-reported by test subjects, therefore the answers could have been biased. It also only studied a specific group.
“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,” Rasla said.
Even so, he says, there’s one important takeaway: “If someone is a normal weight, keep it stable.”