Effect of meal timing on postprandial glucose responses to a low glycemic index meal: A crossover trial in healthy volunteers

Glucose metabolism is, in part, regulated by the circadian rhythm. Postprandial glucose response is exaggerated and insulin sensitivity is reduced at night compared with the morning. Sustained poor glucose tolerance may be related to the increased risk of type-2 diabetes mellitus and cardiovascular disease experienced by shift workers. Manipulation of meal type may be able to dampen such postprandial excursions. Therefore, the study's aim was to investigate postprandial glucose and insulin responses to a low glycemic index (GI) meal in the morning compared to night in healthy volunteers. An oral glucose tolerance test (OGTT), was undertaken to confirm diurnal glucose response. Participants consumed a glucose solution at 0800h (morning) and 2000h (evening). In a separate trial, participants consumed a low GI meal (3.3 MJ, 48% energy (E) from carbohydrate, 40%E from fat and 11%E from protein, 22 g fiber) at 0800h, 2000h and 0000h (midnight). Postprandial glucose and insulin were collected over 3 h. Incremental area under the curve (iAUC) was calculated and significance tested using Wilcoxon-signed rank. A p-value