Ingestion of an exogenous ketone monoester improves the glycemic response during oral glucose tolerance test in individuals with impaired glucose tolerance: A cross‐over randomized trial

Aims/Introduction As a low‐carbohydrate diet and the use of sodium–glucose transporter‐2 inhibitors are both known to increase D‐beta‐hydroxybutyrate levels, the effect of these levels on glucose metabolism has attracted attention. We investigated the acute effects of ketone monoester (KM) ingestion on blood glucose levels during the 75‐g oral glucose tolerance test (OGTT) in participants with impaired glucose tolerance. Materials and Methods Nine Japanese adults aged 48–62 years (4 men, 5 women) with impaired glucose tolerance participated in this study. After participants fasted overnight, we carried out OGTT for 180 min with and without KM ingestion on two separate days in a randomized cross‐over design. We compared the area under the curve (AUC) of D‐beta‐hydroxybutyrate, glucose, insulin, C‐peptide, glucagon and free fatty acids during OGTT. Results The AUC of D‐beta‐hydroxybutyrate during OGTT was significantly higher with KM than without KM (KM 5995.3 ± 1257.1 mmol/L·h; without KM 116.1 ± 33.9 mmol/L·h, P