Baseline Metabolic Variables Do Not Predict Weight Regain in Premenopausal Women

Obesity-induced and weight-loss-induced physiological factors affecting weight regain

Weight regain after successful weight loss resulting from lifestyle interventions is a major challenge in the management of overweight and obesity. Knowledge of the causal mechanisms for weight regain can help researchers and clinicians to find effective strategies to tackle weight regain and reduce obesity-associated metabolic and cardiovascular complications. This Review summarizes the current understanding of a number of potential physiological mechanisms underlying weight regain after weight loss, including: the role of adipose tissue immune cells; hormonal and neuronal factors affecting hunger, satiety and reward; resting energy expenditure and adaptive thermogenesis; and lipid metabolism (lipolysis and lipid oxidation). We describe and discuss obesity-associated changes in these mechanisms, their persistence during weight loss and weight regain and their association with weight regain. Interventions to prevent or limit weight regain based on these factors, such as diet, exercise, pharmacotherapy and biomedical strategies, and current knowledge on the effectiveness of these interventions are also reviewed.

Association between Fat-Free Mass Loss after Diet and Exercise Interventions and Weight Regain in Women with Overweight

PURPOSE

This study aimed to determine if percent fat-free mass loss (% FFML) after diet alone, diet plus aerobic, or diet plus resistance exercise is a predictor of weight regain in women with overweight.

METHODS

One hundred and forty-one premenopausal women with overweight (body mass index, 28 ± 1 kg·m -2 ; age, 35 ± 6 yr) enrolled in a weight loss program to achieve a body mass index <25 kg·m -2 (diet alone, diet plus resistance, or diet plus aerobic exercise) and were followed for 1 yr. Body weight and composition (with dual-energy x-ray absorptiometry) were measured at baseline, after weight loss, and at 1 yr.

RESULTS

Participants lost 12.1 ± 2.6 kg of body weight, 11.3 ± 2.5 kg of fat mass, and 0.5 ± 1.6 kg of fat-free mass during the weight loss intervention, followed by weight regain at 1 yr (6.0 ± 4.4 kg, 51.3% ± 37.8%; P < 0.001 for all). % FFML was -3.6 ± 12.4, and a greater % FFML was associated with more weight regain ( r = -0.216, P = 0.01, n = 141), even after adjusting for the intervention group ( β = -0.07; 95% confidence interval, -0.13 to -0.01; P = 0.017).

CONCLUSIONS

% FFML is a significant predictor of weight regain in premenopausal women with overweight. These results support strategies for conserving fat-free mass during weight loss, such as resistance training. Future research should try to identify the mechanisms, at the level of both appetite and energy expenditure, responsible for this association.

Body mass cycling and predictors of body mass regain and its impact on cardiometabolic health

Caloric restriction (CR) is the first line intervention to reduce adiposity and total body mass (BM) to improve insulin resistance and ameliorate metabolic derangements. However, the lost adipose mass is difficult to maintain reduced in the long term due to several factors including compensatory changes in orexigenic hormones, adipokine release, pro-inflammatory state, adipose tissue morphology, and resting metabolic rate as a consequence of the caloric deficit. Hence, most patients undergoing a BM reduction intervention ultimately regain the lost mass and too often additional adipose mass overtime, which is hypothesized to have increased deleterious effects chronically. In this mini-review we describe the effects of BM cycling (loss and regain) on insulin resistance and cardiometabolic health and factors that may predict BM regain in clinical studies. We also describe the factors that contribute to the chronic deleterious effects of BM cycling in rodent models of diet-induced obesity (DIO) and other metabolic defects. We conclude that most of the improvements in insulin resistance are observed after a profound loss in BM regardless of the diet and that BM cycling abrogates these beneficial effects. We also suggest that more BM cycling studies are needed in rodent models resembling the development of type 2 diabetes mellitus (T2DM) in humans.