Weight cycling, also known as yo-yo dieting, is the repeated loss and gain of weight, resembling the up-down motion of a

yo-yo A yo-yo (also spelled yoyo) is a toy consisting of an axle connected to two cylinder, disks, and a string looped around the axle, similar to a wikt:spool, spool. It is an ancient toy with proof of existence since 500 BCE. The yo-yo was also ca ...

. Many dieters are initially successful in the pursuit of

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other con ...

but unsuccessful in maintaining the loss long-term and gain the weight back. The dieter then seeks to lose the regained weight, and the cycle begins again. Other individuals cycle weight deliberately in service of

bodybuilding Bodybuilding is the use of progressive resistance exercise to control and develop one's muscles (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuses ...

or athletic goals. It continues to be debated whether weight cycling causes increased risk of later obesity or cardiometabolic disease.

Causes

Dieting

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

and pride in their rejection of food. Over time, however, the limits imposed by such extreme diets cause effects such as depression or

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

that make the diet impossible to sustain. Ultimately, the dieter reverts to their old eating

habit A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously.

s, 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.

Sports

In some sports where an athlete's weight is important, such as those that use

weight class Weight classes are divisions of competition used to match competitors against others of their own size. Weight classes are used in a variety of sports, especially combat sports (such as boxing, kickboxing, mixed martial arts and wrestling). Alter ...

es or aesthetics, it is common for athletes to engage in weight cycling. Weight cycling is common among competitive

combat sports A combat sport, or fighting sport, is a competitive contact sport that usually involves one-on-one combat. In many combat sports, a contestant wins by scoring more points than the opponent, submitting the opponent with a hold, disabling the oppon ...

athletes, including minors.

Mechanism

The process of regaining weight and especially body fat is further promoted by the high metabolic plasticity of skeletal muscle. The Summermatter cycle explains how skeletal muscle persistently reduces energy expenditure during dieting. In addition, food restriction increases physical activity which further supports body weight loss initially. Such weight regain in the form of preferential catch-up-fat is well documented after weight loss due to malnutrition, cancer, septic shock or AIDS and thus constitutes a general phenomenon related to weight loss.

Health effects

It continues to be debated whether weight cycling has negative health effects. A 2019 systematic review and meta-analysis found that "Body-weight fluctuation was associated with higher mortality due to all causes and CVD and a higher morbidity of CVD and hypertension." A 2019 review found that self-reported weight cycling was correlated with an increased risk of endometrial cancer. Weight cycling is also correlated with

kidney cancer Kidney cancer, also known as renal cancer, is a group of cancers that starts in the kidney. Symptoms may include blood in the urine, lump in the abdomen, or back pain. Fever, weight loss, and tiredness may also occur. Complications can include ...

, independently of whether the person is overweight. A 2021 systematic review and meta-analysis found that "weight cycling was a strong independent predictor of new-onset

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

". Weight cycling is also associated with poorer mental health.

References