Effects of repeated weight cycling on non-alcoholic steatohepatitis in diet-induced obese mice.

Lifestyle interventions remain the treatment of choice for patients with obesity and metabolic complications, yet are difficult to maintain and often lead to cycles of weight loss and regain (weight cycling). Literature on weight cycling remains controversial and we therefore investigated the association between weight cycling and metabolic complications using preexistent obese mice. Ldlr-/-.Leiden mice received a high-fat diet (HFD) for 20 weeks to induce obesity. Subsequently, weight-cycled mice were switched between the healthy chow diet and HFD for four 2-week periods and compared to mice that received HFD for the total study period. Repeated weight cycling tended to decrease body weight and significantly reduced fat mass, whereas adipose tissue inflammation was similar relative to HFD controls. Weight cycling did not significantly affect blood glucose or plasma insulin levels yet significantly reduced plasma free fatty acid and alanine transaminase/aspartate transaminase levels. Hepatic macrovesicular steatosis was similar and microvesicular steatosis tended to be increased upon weight cycling. Weight cycling resulted in a robust decrease in hepatic inflammation compared to HFD controls while hepatic fibrosis and atherosclerosis development were not affected. These results argue against the postulate that repeated weight cycling leads to unfavorable metabolic effects, when compared to a continuous unhealthy lifestyle, and in fact revealed beneficial effects on hepatic inflammation, an important hallmark of non-alcoholic steatohepatitis.

A Qualitative Model of Weight Cycling.

Weight cycling is a likely consequence of striving to lose weight after internalizing body image ideals, making upward social comparisons, and experiencing weight stigma. Despite weight cycling's potential physical and psychological consequences, the interplay of weight cycling, social pressures, and experienced and internalized stigma have not been qualitatively explored. Thus, through in-depth interviews of 36 weight-cycling adults, this study sought to understand how people negotiate weight cycling. Interviews informed the development of a qualitative model of weight cycling, which was derived from a theory-neutral inductive analysis. The model's stages included entering the cycle, undergoing the cycle, and challenging the cycle. Participants were triggered to enter the cycle due to weight stigma caused by social pressures. Within the cycle, interviewees internalized weight stigma and engaged in disordered weight management behaviors. Some participants challenged the cycle by becoming more self-aware and mitigating their toxic dieting behaviors. However, it was very difficult, if not impossible, for many to fully exit weight cycling and the restraints of previous weight management thinking and patterns. Our investigation underscores the seriousness of weight cycling and suggests ways to combat weight cycling on both macro and individual levels. It may also be useful to consider weight cycling as disordered eating in hopes of shifting society's dangerous focus on rapid weight loss.

The Physiological Effects of Weight-Cycling: A Review of Current Evidence.

PURPOSE OF REVIEW: There is a common perception among the public that yo-yo dieting, defined as repeated cycles of weight loss followed by weight regain, results in accumulation of fat in the body and lower metabolic rate, thus hindering subsequent attempts to lose weight. We evaluated the effects of weight-cycling on body weight and body mass index (BMI), body composition including fat mass (FM) and lean body mass (LBM), and resting metabolic rate (RMR), by systematically reviewing existing scientific literature. RECENT FINDINGS: Twenty-three cross-sectional and cohort studies (including subjects with a history of weight-cycling compared to those without such history) and interventional studies (evaluating physiological effects during one or more cycles of weight loss and regain) were identified, conducted in generally healthy adults across various age groups, races, and both genders, who had normal weight, overweight, or obesity. Eighteen studies investigated the association between weight-cycling and body weight or BMI, and thirteen of them found no significant association. Fifteen out of twenty studies also found no increase in FM, and none of eighteen studies found a decrease in LBM. Twelve out of fourteen studies reported no adverse changes in RMR either. The overwhelming majority of evidence suggests that weight-cycling (yo-yo effect) is not associated with any adverse effects in body weight, body composition, and metabolic rate. Accordingly, healthy individuals who struggle with overweight or obesity should not be discouraged from repeated attempts to lose the excess weight.

An adaptive response to uncertainty can lead to weight gain during dieting attempts.

BACKGROUND AND OBJECTIVES: Peoples' attempts to lose weight by low calorie diets often result in weight gain because of over-compensatory overeating during lapses. Animals usually respond to a change in food availability by adjusting their foraging effort and altering how much energy reserves they store. But in many situations the long-term availability of food is uncertain, so animals may attempt to estimate it to decide the appropriate level of fat storage. METHODOLOGY: We report the results of a conceptual model of feeding in which the animal knows whether food is currently abundant or limited, but does not know the proportion of time, there will be an abundance in the long-term and has to learn it. RESULTS: If the food supply is limited much of the time, such as during cycles of dieting attempts, the optimal response is to gain a lot of weight when food is abundant. CONCLUSIONS AND IMPLICATIONS: This implies that recurring attempts to diet, by signalling to the body that the food supply is often insufficient, will lead to a greater fat storage than if food was always abundant. Our results shed light on the widespread phenomenon of weight gain during weight cycling and indicate possible interventions that may reduce the incidence of obesity.