Influence of Dairy Protein Breakfast on Glycemia, Weight Loss and Clock Genes in T2D

Increased circadian glucose excursions and overall postprandial glycemia (PPG) are linked to HbA1c and cardiovascular risk in T2D. Most of the metabolic pathways involved in PPG i.e. secretion of insulin and glucagon-like peptide-1 (GLP-1), are controlled by circadian clock genes (CG). However, the CG regulation is bidirectional, indeed high protein breakfast (B), by increasing insulin and GLP-1 upregulate CG expression leading to reduced overall PPG, HbA1c and weight loss (WL) in T2D. Furthermore in recent study the investigators have shown that in type 2 diabetic patient treated with insulin a diet with 3 Meal Diet consisting in high energy and protein breakfast, medium sized lunch and low energy dinner, with selective time restriction from carbohydrate consumption after 15:00, designed as Bdiet; was more effective approach for reduction of overall PPG, HbA1c and for upregulation of Clock Genes (CG) mRNA expression compared to isocaloric 6 Meal Diet, with calories and macronutrient evenly distributed along the day in three main meals and 3 snack in between. As the beneficial effects of high energy and protein breakfast in 3Meal diet on the reduction of body weight, overall glycemia and up regulation CG expression, have been demonstrated, in recent studies, we hypothesized that some sources of protein in the breakfast may exert be more beneficial than other source of protein on body weight, PPG, HbA1c and on CG expression Milk consumption is linked to lower risk for obesity and T2D. In acute studies, the addition of milk to carbohydrates in B, displayed greater lowering effect of glucose response after breakfast, lunch and dinner compared with other protein sources. However the effect of a diet 3Mdiet with high energy and dairy protein breakfast (MBdiet), on overall PPG, weight loss HbA1c, the effect on effect on circadian clock genes and AMPK mRNA expression and on the postprandial glucose, insulin, C-peptide, GLP-1, PYY, CCK, ghrelin, DPP4 plasma activity and appetite has never been explored and never were compared to isocaloric 3Mdiet with other then dairy protein source of protein (OBdiet) in long term study in T2D individuals . The investigators hypothesize that a diet with high energy and protein breakfast consisting on milk and dairy proteins (MBdiet), by enhancing clock gene expression will lead to more efficient weight loss reduction of overall PPG, and glucose control (HbA1c), compared to a diet with other (non dairy) proteins in the breakfast (OBdiet). The investigators also hypothesize that the dairy breakfast effects in MBdiet may be mediated, at least in part, by integration of events that promote greater postprandial glucose insulin, C-peptide, GLP-1, PYY, and CCK, and greater suppression of ghrelin appetite and DPP4 plasma activity,