Weight Cycling Even In Absence of Obesity Bad for Your Heart
Weight cycling, sometimes call yo-yo dieting, is a condition where a person loses weight and then regains that amount or more. Research is not clear if weight cycling leads to a slower metabolism, making it harder to lose weight in the future, but investigators are linking yo-yo dieting with an increased risk of cardiovascular disease.
Dr. Molly Waring of the University of Massachusetts Medical Center found that even when remaining within a normal range for BMI (19-24.9), those whose weight went up and down over a two year period had a higher risk of cardiovascular disease and death similar to those who were overweight.
Waring and her team used data from the Framingham Heart Study to examine a person’s weight across a spectrum of years rather than a single point in time. The data included 1429 participants aged 40 to 55 years old. Weight cycling was defined as a change of one BMI unit within a two year period, or only about 5 pounds for a woman 5 feet tall.
Those who were normal weight, but whose weight fluctuated at least one BMI point, had a 50% greater risk of cardiovascular disease events and a 40% greater risk of cardiovascular mortality. They were also at a significantly increased risk of cerebrovascular accidents (stroke) when compared to normal weight patients who remained at a steady BMI. For those who were already overweight (BMI 25 to 30), those who fluctuated and those who remained constant were about equal in their risk for cardiovascular or cerebrovascular events.
A recent study published in the February Journal of the American Dietetic Association explored the link on normal-weight, yet high body fat percentage, individuals. Even those who maintained a healthy weight on the scale were at risk for increased insulin resistance and elevated blood lipid levels when body fat was high. These conditions can lead to metabolic syndrome and cardiovascular disease.
Dr. Waring said, "Among people who are overweight, those whose weight varied within the two-year period were not at any higher risk of cardiovascular disease and death than those overweight individuals whose weight remained steady. I think that's a positive finding from the study, because we know how difficult it is for patients to lose weight and to keep it off. It's encouraging in that if they are trying to lose weight but gain it back because they're not able to maintain the lifestyle changes, it's not putting them at greater risk. The message is to keep trying."
The results of the study were presented at the American Heart Association Nutrition, Physical Activity, and Metabolism 2010 Conference.