Genetic Predisposition and Body Weight Regulation. Evaluation of Target-genes in Overweight and Obese Adults, Under Different Dietary Interventions.

Increased body weight leading to the development and the establishment of overweight and obesity, has a growing detrimental effect on overall health status and quality of life. Latest research has been focusing on the direct influence of dietary habits on body weight regulation and its synergistic effect with genetic predisposition. The synergistic effect of genetic makeup and dietary habits constitute a major contributing factor, specifically in its manifestation on parameters of the cardiometabolic profile of individuals with elevated body weight.

In this context, the aim of the present study is to investigate the effect of two hypocaloric diets with different macronutrient content (a high-carbohydrate/low-fat and a high-protein one) on the body weight loss of an overweight and/or obese adult, Greek population. Moreover, the study aims to explore gene-diet interactions between obesity and weight loss- related target genes and adherence to the proposed dietary schemes. It will further examine influences of the aforementioned factors on body composition, anthropometric indices, such as waist circumference, biochemical biomarkers related to cardiometabolic control and parameters of lifestyle, such as sleep quality.

More specifically, 300 participants will be allocated into two groups, following either the high-carbohydrate/low-fat diet or the high-protein diet, for a duration of 3 months. Volunteers will participate in in-person meetings, at baseline and at three months after the beginning of the intervention. Anthropometric measurements and collection of blood samples will take place in each meeting. Demographic data and data on family and medical history, dietary habits, adherence to the Mediterranean diet, overall health status and physical activity will be collected at baseline. Participants will be provided with nutritional counselling and support both at the beginning and throughout the intervention. Participants will further report their monthly progress by completing online questionnaires (namely concerning their body weight, overall health status, physical activity and sleep quality), via use of an online assessment tool developed by our team.

The effect of the intervention will be evaluated using anthropometric indices, body composition markers and biochemical biomarkers of cardiometabolic control, pre- and post- intervention. Gene-diet interactions will be assessed via genotyping of DNA samples and statistical analyses will take place via statistical packages, such as PLINK v.1.9.