Metabolic disturbances due to a high-fat diet in a non-insulin-resistant animal model

OBJECTIVE: Shift workers have metabolic changes more often than day workers. It is also known that night workers prefer foods high in saturated fat. Such data suggest that shift workers are prone to cardiovascular disease. Therefore, the objective of this study was to propose an animal model to test the effect of high-fat diet (HFD) based on shift workers' diet. METHODS: This is an experimental study with 20 Wistar rats. Ten rats were allocated to the control group (CG) and were fed standard diet. Ten rats were allocated to the experimental group (EG) and were fed HFD (45% fat). Serum triglycerides (TG), glucose and high-density lipoprotein-cholesterol (HDL-cho) were measured 5, 10 and 15 weeks after the beginning of the study. The amount of visceral adipose tissue (VAT) was determined. Body weight was assessed weekly, and food and water intake were measured daily. Student's t-test was used for independent samples, and P<0.05 was considered significant. RESULTS: After 15 weeks of intervention, the EG showed increased serum levels of TG (P=0.001) and glucose (P<0.001) and decreased HDL-cho (P<0.001) when compared with the CG. The EG showed increased VAT (P=0.005) and liver weight (P=0.01). Food intake and water intake were higher in the CG (P<0.001 and P<0.001, respectively), whereas energy intake showed no difference (P=0.48). No difference was found in the weight of adrenal glands (P=0.07) and body weight (P=0.63). CONCLUSIONS: The experimental diet was effective to show changes in the serum levels of glucose, TG and HDL-cho and visceral fat in spite of no change in body weight in 15 weeks.