Background: Studies have revealed that time-restricted feeding affects the fat oxidation rate; however, its effects on the fat oxidation rate and hyperlipidemia following high-fat meals are unclear. This study investigated the effects of 5-day time-restricted feeding on the fat oxidation rate and postprandial lipemia following high fat meals. Methods: In this random crossover experimental study, eight healthy male adults were included each in the 5-day time-restricted feeding trial and the control trial. The meals of the time-restricted feeding trial were provided at 12:00, 16:00, and 20:00. The meals of the control trial were provided at 08:00, 14:00, and 20:00. The contents of the meals of both trials were the same, and the calories of the meals met the 24-hour energy requirement of the participants. After 5 days of the intervention, the participants consumed high-fat meals on the sixth day, and their physiological changes were determined.

The experiment was conducted over 6 days. On the first day, the participants arrived at the laboratory at 08:00 and quietly rested for 20 minutes in the supine position; gas analyzers were used to record their energy consumption. Subsequently, the participants were randomly allocated to the time-restricted feeding trial or the control trial. The meals of the time-restricted feeding trial were provided at 12:00, 16:00, and 20:00, and the participants were required to consume all the food during this time. The meals of the control trial were provided at 08:00, 14:00, and 20:00, but the consumption time was not limited. In addition to regular meals, a snack with approximately 200 calories was provided to the participants for consumption. The participants in the time-restricted feeding trial were only allowed to consume the snack from 12:00 to 20:00, whereas no restrictions were imposed on the control trial for snack consumption. The meals of the participants were provided by dieticians. Based on the results of the pretest, the calories of each meal met the daily energy requirement of the participants. The macronutrient consumption for TRF and CON were listed in table 1.

After experiment completion on the fifth day, the participants returned to the laboratory on the eighth day from 08:00 to 09:00. They rested for 10 minutes in the supine position, and gas analyzers were used to collect the gas data of the participants for 20 minutes. Next, a catheter was inserted into the forearm of each participant to collect fasting blood samples. After blood sample collection, the participants were provided with a specific high-fat meal. The participants rested quietly in the laboratory for 4 hours, and their blood lipid changes during this period were observed.

Inclusion Criteria:

• All the participants had not undergone physical training;
• they did not exercise regularly;
• and they did not have any diseases that would prevent them from performing exercises, such as high blood pressure, hyperlipidemia, heart disease, joint disease, and osteoporosis.

Exclusion Criteria:

• Undergone physical training;
• Exercise regularly;
• Have any diseases that would prevent them from performing exercises, such as high blood pressure, hyperlipidemia, heart disease, joint disease, and osteoporosis.