Losing weight then gaining it back again in a pattern may be bad for the health, particularly for normal-weight women, research presented at the American Heart Association’s Scientific Sessions reports.
Dr. Somwail Rasla, an internal medicine resident at Memorial Hospital of Rhode Island at Brown University and lead author on the study, says,
We found that those with normal weight were the highest at risk for both sudden cardiac death and coronary heart disease death.
Rasla and his team examined data from 158,000 women older than 50, who had reported their own weight history, and had been categorized as normal weight, overweight or obese. The women were tracked for 11 years to check on sudden cardiac death and death from coronary heart disease, TIME reports.
Women who were of normal weight at the start of the study, but reported a repetitive loss-gain cycle – shedding over 10 pounds then regaining it more than four times over – were 3.5 times more likely to experience sudden cardiac death than women with stable weights. Women with yo-yo weights were also at a 66% increased risk of dying from coronary heart disease.
However, weight cycling did not appear to increase the risks for overweight or obese people.
There are many theories as to why weight fluctuations court such drastic consequences, the researchers say. One is that when weight is gained then lost, variables like heart rate, blood pressure, cholesterol and glucose also waver. If this pattern is repeated enough, these factors are less likely to return to normal levels. Yo-yo weights may also cause insulin resistance, which heightens the risk for coronary heart disease.
Rasla says the reason these health problems appear to affect woman of normal weight more is likely due to their vulnerability. Other studies have shown that women of health weight are more likely to die from heart failure compared to obese women. He explains, “Obese people have higher blood pressure, high diabetes but over a long period of time, and it’s been found that their bodies develop a compensatory adaptive mechanism to different diseases.” Women who don’t get sick as often don’t have the same defenses, and may be more susceptible to these health conditions.
Rasla says the research needs to be replicated in men and in different age groups before definitive conclusions can be made. In addition, there could be other factors at work when it comes to heart health.
The study does not discourage people from losing weight, Rasla emphasizes. However, it does pay to be cautious, and the best way to stay healthy is to maintain a normal weight, he adds.