PT - JOURNAL ARTICLE AU - Haldar, Sumanto AU - Egli, Leonie AU - De Castro, Carlos Antonio AU - Tay, Shia Lyn AU - Koh, Melvin Xu Nian AU - Darimont, Christian AU - Mace, Katherine AU - Henry, Christiani Jeyakumar TI - High or low glycemic index (GI) meals at dinner results in greater postprandial glycemia compared with breakfast: a randomized controlled trial AID - 10.1136/bmjdrc-2019-001099 DP - 2020 Apr 01 TA - BMJ Open Diabetes Research & Care PG - e001099 VI - 8 IP - 1 4099 - http://drc.bmj.com/content/8/1/e001099.short 4100 - http://drc.bmj.com/content/8/1/e001099.full SO - BMJ Open Diab Res Care2020 Apr 01; 8 AB - Introduction While circadian control of glucose metabolism is well known, how glycemic index (GI) of carbohydrate-rich meals interacts with time of consumption (breakfast or dinner) to influence postprandial (PP) glucose homeostasis is less well established. The objective of the study was to assess markers of PP glucose homeostasis following high or low GI test meals (TM) consumed either at breakfast or at dinner and following consumption of the subsequent standardized meals (SSM).Research design and methods Randomized crossover trial in 34 healthy, Chinese, elderly volunteers (mean±SEM age, 56.8±0.83 years), who completed 4 separate study sessions per-protocol, consisting of a high-GI breakfast, low-GI breakfast, high-GI dinner and low-GI dinner TM, followed by a SSM at the subsequent eating occasion. Blood samples were taken for 3 hours after each TM and SSM for glucose, insulin, glucagon, free fatty acids (FFA) and triglycerides (TG) measurements.Results Consuming TM at dinner produced greater PP glycemia than breakfast both after TM and SSM (both p<0.0001), irrespective of GI. High-GI TM also produced greater PP glycemia than low-GI TM, both after TM and SSM (both p<0.01), irrespective of time of consumption. No interaction between GI and time were found on PP glycemia, indicating parallel, but independent effects. Combined total areas under the curve of TM+SSM for PP glucose (p<0.0001), PP TG (p<0.0001) and PP FFA (p<0.0001) were all greater when TM taken during dinner compared with breakfast.Conclusions Carbohydrate-rich meals consumed at dinner leads to significantly worse PP glucose homeostasis than when consumed at breakfast, on top of the independent GI effect of the meal. This may have implications to future type 2 diabetes risk. Moreover, future studies investigating GI/glycemic load (GL) and disease risk associations should factor in timing of GL consumption as an additional variable.Trial registration number NCT02927600.