Yo-yo dieting or yo-yo effect, also known as weight cycling, is a term coined by kelly D.Brownell at Yale University, in reference to the cyclical loss and gain of weight, resembling the up-down motion of a Yo Yo. In this process, the dieter is initially successful in the pursuit of Weight Loss but is unsuccessful in maintaining the loss long-term and begins to gain the weight back. The dieter then seeks to lose the regained weight, and the cycle begins again.
The reasons for yo-yo dieting are varied but often include embarking upon a hypocaloric diet that was initially too extreme. At first the dieter may experience elation at the thought of weight loss and pride in their rejection of food.Over time, however, the limits imposed by such extreme diets cause effects such as depression or fatigue that make the diet impossible to sustain. Ultimately, the dieter reverts to their old eating habits. now with the added emotional effects of failing to lose weight by restrictive diet. Such an emotional state leads many people to eating more than they would have before dieting, causing them to rapidly regain weight.