[Effect of high-fat diet and food restriction on energy metabolism in obesity-prone and obesity-resistant rats].

Objective: To explore the effect of high-fat diet and food restriction on energy metabolism in obesity-prone (OP) and obesity-resistant (OR) rats.

Methods: Sixty male Sprague-Dawley (SD) rats were divided into OP, OR and control groups according to their body weight gain after fed with high-fat diet for 3 wk. OP and OR groups were fed with high-fat diet in the following 12 wk to promote the development of obesity. Then one-half of the rats of each group began to food restriction and were allowed access to 50% of their individual baseline mean daily food intake each day, while the other half were maintained on ad libitum food for 2 wk. Basal metabolic rate (BMR), resting metabolic rate (RMR) of each group were measured by indirect calorimetry during the high-fat diet feeding and food restriction conditions. After the rats were sacrificed, body fat content was measured.

Results: OR rats had significantly higher BMR and RMR than the other two groups during high-fat diet feeding condition. There was no significant difference between OP and control group. Food restriction led to a reduction in BMR and RMR in all groups. OR rats showed a significantly greater reduction. OP group showed a significant decrease in body fat weight and fat content during the food restriction period, while there was no significant differences in OR rats.

Conclusion: There are significant differences between OP and OR rats in BMR and RMR either in high-fat diet feeding condition or food restricted state. OR rat has the ability to sense and respond to energy imbalance more accurately than OP rat.