Resistant starch and exercise independently attenuate weight regain on a high fat diet in a rat model of obesity.

Janine A Higgins,James O Hill,Amy Steig,Holly R Wyatt,Ginger C Johnson,Ian L Brown,Matthew R Jackman,Paul S Maclean

doi:10.1186/1743-7075-8-49

Abstract

BackgroundLong-term weight reduction remains elusive for many obese individuals. Resistant starch (RS) and exercise may be useful for weight maintenance. The effects of RS, with or without exercise, on weight regain was examined during relapse to obesity on a high carbohydrate, high fat (HC/HF) diet.MethodsObesity-prone rats were fed ad libitum for 16 weeks then weight reduced on a low fat diet to induce a 17% body weight loss (weight reduced rats). Weight reduced rats were maintained on an energy-restricted low fat diet for 18 weeks, with or without a daily bout of treadmill exercise. Rats were then allowed free access to HC/HF diet containing low (0.3%) or high (5.9%) levels of RS. Weight regain, energy balance, body composition, adipocyte cellularity, and fuel utilization were monitored as rats relapsed to obesity and surpassed their original, obese weight.ResultsBoth RS and exercise independently attenuated weight regain by reducing the energy gap between the drive to eat and suppressed energy requirements. Exercise attenuated the deposition of lean mass during relapse, whereas its combination with RS sustained lean mass accrual as body weight returned. Early in relapse, RS lowered insulin levels and reduced the deposition of fat in subcutaneous adipose tissue. Exercise cessation at five weeks of relapse led to increased weight gain, body fat, subcutaneous adipocytes, and decreased lean mass; all detrimental consequences to overall metabolic health.ConclusionsThese data are the first to show the complimentary effects of dietary RS and regular exercise in countering the metabolic drive to regain weight following weight loss and suggest that exercise cessation, in the context of relapse on a HC/HF diet, may have dire metabolic consequences.

Highlights

Long-term weight reduction remains elusive for many obese individuals
In response to the calorierestricted, weight loss intervention, rats lost an average of 17.0 ± 0.5% of body weight
At the end of weight maintenance, the SED and EX groups were similar in weight, total bone mass, bone density, fat free mass (FFM), fat mass (FM), and percent body fat (Table 3)

Summary

Introduction

Long-term weight reduction remains elusive for many obese individuals. Resistant starch (RS) and exercise may be useful for weight maintenance. Weight regain occurs frequently in individuals who have lost weight [1]. Substantial evidence indicates that biological adaptations to weight loss contribute to weight regain. The increase in energy intake and suppressed energy requirements promote the energy imbalance required for weight regain, and, when overfeeding occurs, the peripheral adaptations ensure rapid clearance of ingested nutrients, energetically efficient adipose repletion, and continued signals to the brain that perpetuate the energy imbalance until the lost weight returns. Exercise attenuates weight regain after weight loss from obesity in both humans [13,14] and rodents [12,15]. Treadmill exercise in formerly-obese rodents reduces the rate of regain early in relapse and lowers the steady state weight achieved at the end of relapse [12]. Because exercise affects a number of components in the homeostatic system controlling body weight, it is not surprising that the vast majority of individuals who are successful at keeping weight off long-term include regular, vigorous exercise in their weight maintenance program [16]

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