MAST4HEALTH is set on the concept of a multidisciplinary approach to assess a non-pharmacological intervention for managing NAFLD/NASH, one of the most common complications of obesity and diabetes mellitus in Western populations affecting approximately 50% of diabetics and 76% of obese patients. Because of limitations in current NAFLD treatment therapies, many new efforts focus on exploring non-pharmacologic means for managing the disease and in particular through dietary substances or bioactive phytochemicals in fruits, vegetables, and plants or their products. MAST4HEALTH aims at exploring the effect of Mastiha, a natural product of Greece which was recently shown to possess antioxidant/anti-inflammatory and lipid lowering properties. We designed a multicenter randomized double blind placebo controlled (parallel arm) clinical trial to test the effectiveness of Mastiha supplement as new non-pharmacologic strategy for NAFLD/NASH treatment. MAST4HEALTH will explore gene-diet interactions, more specifically the potential personalized activity of the Mastiha, and correlate genetic and epigenetic markers with metabolomic and intestinal microbiota profiles pre- and post-intervention. The effectiveness of the proposed intervention will be evaluated via clinical and laboratory markers of the disease. To this end, MAST4HEALTH will train a number of researchers and PhD students in multidisciplinary approaches of this survey. MAST4HEALTH is expected to build and enhance cooperation among partners meanwhile strengthening the interaction between our academic and non-academic sectors