People with prediabetes should avoid high-Carbohydrate Foods in the evening

The effect of diurnal distribution of carbohydrates and fat on glycaemic control in humans: a randomized controlled trial. Scientific Reports 7, 2017

Effect of carbohydrate-emphasized test meal (MTT-HC) and fat-emphasized test meal (MTT-HF) on postprandial glucose (area under the curve) in the morning and afternoon in subjects with normal glucose tolerance (NGT, blue) and with impaired glucose metabolism (IFG/IGT, red). © DIfE

The internal clock influences how people with impaired glucose metabolism react to carbohydrate-rich food. Men with prediabetes, abundant consumption of foods containing starch and sugar in the evening had a negative effect on their blood glucose regulation. These are the results of a nutrition study led by the German Institute of Human Nutrition (DIfE).
Furthermore, in the affected men the researchers observed an altered secretion of the intestinal hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), which contribute to the regulation of the glucose metabolism or body weight and whose secretion is subject to a particular circadian rhythm. Thus, the blood levels of the two hormones decreased significantly parallel to the pronounced decrease of glucose tolerance in the afternoons in the affected persons in contrast to the healthy participants.
“The circadian rhythm of the hormonal release thus influences the way we react to carbohydrates,” said endocrinologist Pfeiffer, who heads the Department of Clinical Nutrition at DIfE.

Original publication:
Kessler, K. et al. The effect of diurnal distribution of carbohydrates and fat on glycaemic control in humans: a randomized controlled trial. Sci. Rep. 7, 44170; doi: 10.1038/srep44170 (2017).