Carbohydrate restriction in the morning increases weight loss effect of a hypocaloric Mediterranean type diet: a randomized, parallel group dietary intervention in overweight and obese subjects.

Abstract

The aim of this study was to examine the effect of carbohydrate restriction in the morning in the framework of a hypocaloric Mediterranean diet on weight loss and metabolic parameters. Seventy overweight/obese individuals were randomized to two hypocaloric dietary regimens: one Mediterranean diet (Med-D) and one morning carbohydrate-restriction diet (MCR-D). Participants assigned to the MCR-D were permitted to consume a breakfast low in carbohydrate content, whereas typical Mediterranean morning meals were allowed in the Med-D group. Both diets were identical from midday on. Participants were followed over a period of 2 mo. Individuals in both groups achieved significant reductions in body weight, body mass index, waist circumference, and body fat mass. These reductions were more pronounced in the MCR-D than in the Med-D group (all P < 0.001). More participants in the MCR-D group achieved loss of 5% to 10% of body weight by the end of the first month, as well as 5% to 10% and >10% of body weight by the end of the second month (all P < 0.001). All participants achieved loss of ≥5% baseline body weight by the end of the intervention. Both groups achieved similar reductions in fasting serum glucose, glycated hemoglobin, and serum triacylglycerols as well as improvement in insulin sensitivity. Individuals in the Med-D group showed reductions in total and low-density lipoprotein cholesterol, whereas no such effect was observed in the MCR-D group. Integration of morning carbohydrate restriction into a Mediterranean-type hypocaloric diet resulted in greater weight loss while retaining metabolic benefits in glycemia-related parameters.