History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women, a study from researchers at the Fred Hutchinson Cancer Research Center, published in Metabolism, claims to have shown that people who "yo-yo diet" do not suffer any lasting metabolic changes as a result. That is, according to the study, if you diet then gain weight repeatedly, you will not find it more difficult to lose weight on subsequent diets.
The analysis aimed to determine whether women with a history of moderate or severe weight cycling were at a disadvantage compared to non-weight-cyclers when it came to losing weight. Of the study participants overall, 18 percent (77 women) met the criteria for severe weight cycling (having reported losing 20 or more pounds on three or more occasions) and 24 percent (103 women) met the criteria for moderate weight cycling (having reported losing 10 or more pounds on three or more occasions).
Although severe weight cyclers were, on average, nearly 20 pounds heavier than non-cyclers at the start of the study, at the end of the study the researchers found no significant differences between those who yo-yo dieted and those who didn't with regard to the ability to successfully participate in diet and/or exercise programs. The cyclers also did not differ from the non-cyclers with regard to the impact of diet or diet-plus-exercise on weight loss, percentage of body fat and lean muscle mass gained or lost. Other physiological factors such as blood pressure, insulin sensitivity, and blood concentrations of hormones such as leptin (which helps make one feel full) and adiponectin (which helps regulate glucose levels) also did not differ significantly among those whose weight fluctuated and those whose did not.