Figure 1.

The effect of macronutrients on the gut and liver

(A) normal nutrient metabolism. In health, dietary fiber is metabolized by gut bacteria to produce short-chain fatty acids (SCFAs), which maintain gut barrier function. This protects the liver from gut-derived endotoxins.

(B) altered nutrient metabolism. Dietary imbalance induces gut dysbiosis and increases gut permeability. This increases the translocation of gut content to the liver, promoting the development of nonalcholic fatty liver diseases (NAFLD) and nonalcholic steatohepatitis (NASH). Arrows denote sequential metabolic effects. Broader arrows indicate greater effect. The balance scale indicates the imbalance in dietary consumption. This figure was created with Biorender.com.