We’ve all either been through it or had at least one friend that went through it: you start a diet, lose weight, but after a while gain it back. The infamous yo-yo effect has become a fierce enemy of dieters and now, a new study reports that it might also increase the risk of heart diseases.

Delicious, but probably not a part of too many diets. Many people rebound after embarking on a too ambitious effort. Image in public domain.

The world is facing an obesity crisis and the best way to tackle that is through a healthier diet. But, too often people embark on a diet that’s too optimistic or just not sustainable in our day to day life. At first, dieters might feel great satisfaction seeing how they lose weight and improve their health, but in time, fatigue or even depression can make the diet much more difficult to sustain. Ultimately, the dieter will revert to old eating habits, with the added mental pressure of failure to keep up with dieting.

The process of losing and then gaining weight was now analyzed in a new study. Researchers studied 485 women, 61% of which are ethnical minorities, and asked them to report how many times they lost at least 10 pounds (4.5 kg), only to regain the weight back within a year (excepting pregnancy). They then assessed their cardiovascular health using the American Heart Association’s Life’s Simple 7, a measure of how well people control important heart disease risk factors (including body mass index, cholesterol, blood pressure, blood sugar, smoking, physical activity and diet).

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Surprisingly, 3 in 4 women (73%) experienced at least one yo-yo diet event — some of them experienced up to 20 such episodes in a single year. Notably, women who experienced at least one such event were 82% less likely to have an optimal body mass index and were also 65% less likely to be rated as having an optimal overall health on the Life’s Simple 7 scale. Furthermore, the more yo-yo episodes they had, the worse their overall health was rated.

“Achieving a healthy weight is generally recommended as heart healthy but maintaining weight loss is difficult and fluctuations in weight may make it harder to achieve ideal cardiovascular health,” said 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.

Of course, this is still a correlation-not-causation type of study, and there are also several limitations. In addition to the population sample, which was rather small and not exactly representative of the population at large, the study also did not differentiate between intentional and unintentional weight loss. However, the results seem convincing and are consistent with what previous studies have shown. Researchers now want to see if the results carry over in larger sample sizes.

“We hope to extend the study five to ten years to confirm these results and look at long-term effects,” Aggarwal said. “However, 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.”

They also want to identify exactly how and when these yo-yo episodes are triggered, so that healthy interventions could be planned, especially in younger women.

“The women without a pregnancy history were likely younger and might be those who started weight-cycling at an earlier age. 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,” said Aggarwal.

Results have been presented at the American Heart Association’s Epidemiology and Prevention and have not yet been peer-reviewed.