A peripheral perspective of weight regain

2014 AAHA weight management guidelines for dogs and cats

Communicating and implementing a weight management program for dogs and cats can be a challenging endeavor for veterinarians, but a rewarding one. An effective individualized weight loss program provides a consistent and healthy rate of weight loss to reduce risk of disease, prevent malnutrition, and improve quality of life. Weight loss is achieved with appropriate caloric restriction, diet selection, exercise, and strategies to help modify behavior of both the pet and client. This document offers guidelines and tools for the management of weight loss and long-term maintenance of healthy weight.

Repletion of TNFα or leptin in calorically restricted mice suppresses post-restriction hyperphagia

The causes of post-restriction hyperphagia (PRH) represent a target for drug-based therapies to prevent obesity. However, the factors causing PRH are poorly understood. We show that, in mice, the extent of PRH was independent of the time under restriction, but depended on its severity, suggesting that PRH was driven by signals from altered body composition. Signals related to fat mass were important drivers. Circulating levels of leptin and TNFα were significantly depleted following caloric restriction (CR). We experimentally repleted their levels to match those of controls, and found that in both treatment groups the level of PRH was significantly blunted. These data establish a role for TNFα and leptin in the non-pathological regulation of energy homeostasis. Signals from adipose tissue, including but not limited to leptin and TNFα, regulate PRH and might be targets for therapies that support people engaged in CR to reduce obesity.

Low-carbohydrate high-fat diets: regulation of energy balance and body weight regain in rats

The aim of the current investigations was to examine the effects of a low-carbohydrate high-fat diet (LC-HFD) on body weight, body composition, growth hormone (GH), IGF-I, and body weight regain after stopping the dietary intervention and returning the diet back to standard laboratory chow (CH). In study one, both adolescent and mature male Wistar rats were maintained on either an isocaloric LC-HFD or CH for 16 days before having their diet switched. In study two, mature rats were maintained on either LC-HFD or CH for 16 days to determine the effects of the LC-HFD on fat pad weight. LC-HFD leads to body weight loss in mature rats (P < 0.01) and lack of body weight gain in adolescent rats (P < 0.01). Despite less body weight, increased body fat was observed in rats maintained on LC-HFD (P < 0.05). Leptin concentrations were higher (P < 0.05), and IGF-I (P < 0.01) concentrations were reduced in the LC-HFD rats. When the diet was returned to CH following LC-HFD, body weight regain was above and beyond that which was lost (P < 0.01). The LC-HFD resulted in increased body fat and had a negative effect upon both GH and IGF-I concentrations, which might have implications for the accretion and maintenance of lean body mass (LBM), normal growth rate and overall metabolic health. Moreover, when the LC-HFD ceases and a high-carbohydrate diet follows, more body weight is regained as compared to when the LC-HFD is consumed, in the absence of increased energy intake.

Peripheral metabolic responses to prolonged weight reduction that promote rapid, efficient regain in obesity-prone rats

Weight regain after weight loss is the most significant impediment to long-term weight reduction. We have developed a rodent paradigm that models the process of regain after weight loss, and we have employed both prospective and cross-sectional analyses to characterize the compensatory adaptations to weight reduction that may contribute to the propensity to regain lost weight. Obese rats were fed an energy-restricted (50–60% kcal) low-fat diet that reduced body weight by 14%. This reduced weight was maintained for up to 16 wk with limited provisions of the low-fat diet. Intake restriction was then removed, and the rats were followed for 56 days as they relapsed to the obese state. Prolonged weight reduction was accompanied by 1) a persistent energy gap resulting from an increased drive to eat and a reduced expenditure of energy, 2) a higher caloric efficiency of regain that may be linked with suppressed lipid utilization early in the relapse process, 3) preferential lipid accumulation in adipose tissue accompanied by adipocyte hyperplasia, and 4) humoral adiposity signals that underestimate the level of peripheral adiposity and likely influence the neural pathways controlling energy balance. Taken together, long-term weight reduction in this rodent paradigm is accompanied by a number of interrelated compensatory adjustments in the periphery that work together to promote rapid and efficient weight regain. These metabolic adjustments to weight reduction are discussed in the context of a homeostatic feedback system that controls body weight.