Association between glucose dips and the feeling of hunger in a dietary intervention study among students with early and late chronotype-secondary analysis of a randomized cross-over nutrition trial.

Consumption of foods with high glycaemic index (GI) can cause hyperglycemia, thus increasing postprandial hunger. Since circadian rhythm differs inter-individually, we describe glucose dips after breakfast/dinner with high/medium estimated meal GI among students with early (n = 22) and late chronotype (n = 23) and examine their relation to the feeling of hunger in a secondary analysis of a randomized cross-over nutrition trial. Glucose dips reflect the difference between the lowest glucose value recorded 2-3 h postprandially and baseline, presented as percentage of average baseline level. Associations between glucose dips and the feeling of hunger were analyzed using multilevel linear models. Glucose dips were lower after medium GI meals than after high GI meals among both chronotype groups (p = 0.03). Among early chronotypes, but not among late chronotypes, glucose dip values were lower after breakfast than after dinner (-4.9 % vs. 5.5 %, p = 0.001). Hunger increased throughout the day among both chronotypes but glucose dips were not related to the feeling of hunger at the meal following breakfast. Interestingly, lower glucose dip values 2-3 h postprandially occurred particularly after medium GI meals and were seen after breakfast among early chronotypes. These glucose dips did not predict hunger at meals after breakfast.