For the study, 439 overweight, postmenopausal women, who were not physically active, were randomly assigned to a weight loss diet and/or moderate or vigorous aerobic exercise for 45 minutes a day, five days a week. Just under one-fifth of the women were classified as ‘severe weight cyclers’, having lost at least 20 pounds 3 times previously and a quarter of the women were moderate weight cyclers, as they’d lost 10 pounds at least 3 times. There was a control group of women who didn’t change their diets or exercise habits for reasons of comparison.
The women with a history of yo-yo dieting were heavier and had less favourable metabolic and hormonal profiles than the other women, but these differences did not stem from weight cycling itself, but rather their higher BMI, larger waistlines, and greater percentage of body fat. The results were that, in terms of weight loss and improvements in their metabolic and hormonal profiles, the women with a history of weight cycling had fared at least as well as the other women.
However, what does this prove? Surely if a weight-cycler has lost and gained weight before, they’ll just gain this weight back again. According to researcher Anne McTiernan, MD, PhD, and a member of the Fred Hutchinson Cancer Centre’s Public Health Sciences Division, the team is in the process of analysing the long-term findings of the study as they ‘have been able to follow many of the women out to a couple of years’ says McTiernan. She concluded that if you are a yo-yo dieter, you should keep trying to lose weight nevertheless, because ‘If nothing else, losing weight again gives you a period of time at a lower weight, which improves your health for however long you keep the weight off.’