For overweight people with heart disease, trying and failing to lose weight may be more dangerous than not losing weight at all.
A new retrospective study has concluded that patients whose weight fluctuates the most die twice as quickly or have twice the risk of heart attack or stroke compared to people who maintain a stable body weight.
The study, published in the New England Journal of Medicine, found that when compared to heart patients who kept their weight steady, those with the largest weight changes experienced:
117 percent more heart attacks
124 percent more deaths
This is the first study to measure the effect of yo-yo dieting on health in patients with pre-existing heart disease. It's an analysis of about 9,500 patients involved in a different study that didn't examine reasons for weight changes. Weight was measured an average of 12 times over four years and some patients lost and regained several pounds in between each measurement.
Among the 1,900 patients with the biggest weight changes, 37 per cent had fatal or non-fatal heart attacks, strokes or other heart trouble during the study. That compared with 22 percent of the 1,900 patients whose weight changed the least.
Weight changes in the highest-risk group averaged about 10 pounds (5 kilograms) over four years. In the lowest-risk group, weight changes averaged less than 2 pounds (0.9 kilogram) over the same period. Deaths totalled almost 500 and were more common in patients with the biggest weight swings.
"Back in the 90s there was a study done in patients with no heart disease, who were pretty healthy, that found that weight fluctuations over a decade actually increased the risk of death from heart disease," Sripal Bangalore, M.D., director of the cardiovascular outcomes group at NYU Langone Medical Center. "So we wanted to see if in patients who already have heart disease, where there is so much emphasis on weight loss is this weight cycling harmful."