Metabolic effects of two intermittent fasting protocols compared to caloric restriction in rats

Intermittent fasting (IJ) has been the target of scientific research to improve health and increase longevity. The present study aimed to evaluate the metabolic effects of two IJ protocols, 6 and 12h, compared to dietary restriction. Twenty-eight adult male Wistar rats were used, divided into 4 groups (n=7): Control (C) - standard ad libitum diet; Fasting 12h (J12); Fasting 6h (J6) - Fasting for 6h and Group Dietary restriction of 20% (DR). Body weight, food intake, water intake, urinary and fecal excretion were collected. In the fourth week the behavioral tests for motor system, depression and memory were performed. At the end of the five weeks of the study, euthanasia was performed with blood, organs and abdominal fat collection. Oxidative stress was measured by the determination of thiobarbituric acid reactive substances and reduced hepatic glutathione (SHG). The 6h and 12h fasting as well as the DR did not influence weight gain, CEA, water intake, urinary excretion and behavioral tests. However, both fasting protocols resulted in lower fecal bolus, serum creatinine, hepatic SHG concentrations, and brain weight without altering behavioral tests compared to the DR Group. The 6h fasting promoted higher serum total cholesterol and AST concentrations. It is noteworthy that Group J12 had higher liver weight and Group R12 had higher abdominal fat. It was concluded that the 6h and 12h fasting protocols presented better metabolic effects compared to the caloric restriction of 20%.