Acute effect of late evening meal on diurnal variation of blood glucose and energy metabolism.

Objective: The notion that late evening meal promotes weight gain is popular, and it may also elicit postprandial hyperglycemia, since glucose tolerance decreases during midnight. Diabetic patients with night-eating symptoms, compared with patients without night-eating behaviors, are more likely to be obese and to have elevated A1c. However, epidemiological analysis adjusted for difference in total energy intake did not identify nighttime eating as the risk of obesity. The present study evaluated the effect of a single loading of late evening meal on diurnal variation of blood glucose and 24-h energy expenditure.

Methods: Ten young adults stayed twice in a room-size respiratory chamber for 24 h, in a randomized repeated-measures design. After the entrance to the chamber at 1700 h, the subjects took normal (1900 h) or late (2230 h) evening meal, breakfast and lunch, and remained in the chamber until 1700 h. Time course of blood glucose was measured by continuous glucose monitoring system.

Results: Late evening meal enhanced postprandial blood glucose response to the evening meal and the subsequent breakfast. Overall 24 h average blood glucose level was also elevated by late evening meal. Late evening meal shifted postprandial increase in energy expenditure toward late at night, but overall 24 h energy expenditure remained almost identical in the two dietary conditions.

Conclusions: The present study under controlled sedentary condition supports the notion that a single loading of late evening meal enhances average blood glucose over 24 h, but does not support that late evening meal reduces 24 h energy expenditure.