Noncommunicable chronic disorders (NCDs) are multifactorial disorders that share a state of chronic, low-grade inflammation together with an imbalance of gut microbiota. NCDs are becoming increasingly prevalent worldwide, and mainly in Western countries, with a significant impact on global health.

Societal changes, together with the widespread diffusion of modern agricultural methods and food processing, have led to a significant shift in dietary habits over the past century, with an increased diffusion of the Western diet (WD). WD includes foods high in saturated fat, refined sugars, salt, sweeteners, and low in fiber, and is characterized by overeating, frequent snacking, and a prolonged postprandial state.

An increasing body of evidence supports the association between the diffusion of WD and the rising prevalence of NCDs. WD also negatively affects both gut microbiota and the immune system by driving to microbial alterations, gut barrier dysfunction, increased intestinal permeability, and leakage of harmful bacterial metabolites into the bloodstream, with consequent contribution to the development of systemic low-grade inflammation. In this review article we aim to dissect the role of gut microbiota imbalance and gut barrier impairment in mediating the detrimental effects of WD on the development of NCDs, and to identify potential therapeutic strategies.