Skipping breakfast is an irregular feeding behavior, typically in young people. In our previous study, we established a 4 h-delayed feeding protocol for rats as a breakfast-skipping model and showed that the 4 h-delayed feeding of a high-fat diet led to body weight gain in rats. Excess sucrose induces metabolic syndrome and fatty liver. Recently, excess sucrose intake has received increased attention. Young people generally consume more sugar than adults do. In the present study, we investigated whether a 4 h-delayed feeding promoted high-sucrose diet-induced abnormalities in lipid metabolism, such as fatty liver and obesity in rats. The 4 h-delayed feeding rats showed increased body weight gain, although it did not induce fatty liver and hyperlipidemia compared to normal feeding rats. Serum insulin concentration during the feeding period was higher than in the control rats, suggesting that slight insulin resistance was induced by the 4 h-delayed feeding. The surge in body temperature was also delayed by 4 h in response to the 4 h-delayed feeding. This delay would result in less energy expenditure to increase body weight. The oscillations of hepatic lipid and glucose metabolism-related gene expression were delayed by almost 2-4 h, and the clock genes were delayed by approximately 2 h. The 4 h-delayed feeding induced weight gain by affecting body temperature, insulin resistance, and circadian oscillation of lipid metabolism-related genes in rats fed a high-sucrose diet, suggesting that a high sucrose intake with breakfast skipping leads to obesity.
