In many populations, a frequent consumption of fast food and convenience food is connected with a range of harmful health outcomes, including obesity (especially an increase in visceral fat tissue), disrupted glucose, insulin and leptin homeostasis, lipid and lipoprotein disorders, intestinal dysbiosis, induction of systemic inflammation and oxidative stress, and an increased risk of metabolic syndrome, type 2 diabetes, hypertension, stroke and other cardiovascular diseases [55,56,57]. This evidence concerns the gene LEP and type 2 diabetes mellitus.