Figure 1: Overview at the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The interplay between diet, microbiota, and host genetic variants plays a crucial role in the complex pathogenesis of NAFLD through a variety of mechanisms. The NAFLD patients can now be categorized into different populations based on their insulin sensitivity and genetic predisposition. Insulin resistance is at the center of the NAFLD pathogenic process, and a number of key factors are involved in the development of NAFLD, such as diet, dysbiosis, gut-liver axis, genetic predisposition genes (PNPLA3 and TM6SF2), oxidative stress, MDF (mitochondrial dysfunction), endoplasmic reticulum (ER) stress, de novo lipogenesis, lipotoxicity, and proinflammatory cytokines.