This review examines the impact of diet on gut microbiota and the associated mechanisms in the gut-liver and gut-brain axes. Chronic gut inflammation, driven by dysbiosis in gut microbiota and metabolites, disrupts the intestinal barrier and increases inflammation in various tissues, including the liver and adipose tissues. High-fat and high-carbohydrate diets weaken the adherence of tight junction proteins, leading to increased permeability and the translocation of endotoxins like lipopolysaccharides (LPS) into the bloodstream. This process, known as metabolic endotoxemia, alters gut microbiome composition and reduces the production of beneficial metabolites such as short-chain fatty acids (SCFAs). The review also discusses the effects of artificial sweeteners on gut microbiota and their potential health implications. Additionally, it highlights the role of the gut-liver axis in the development of nonalcoholic fatty liver disease (NAFLD) and the impact of gut microbiota on brain health through the gut-brain axis. The review underscores the need for further research to understand the complex interactions between diet, gut microbiota, and these axes, particularly in the context of obesity, metabolic disorders, and neurological conditions.This review examines the impact of diet on gut microbiota and the associated mechanisms in the gut-liver and gut-brain axes. Chronic gut inflammation, driven by dysbiosis in gut microbiota and metabolites, disrupts the intestinal barrier and increases inflammation in various tissues, including the liver and adipose tissues. High-fat and high-carbohydrate diets weaken the adherence of tight junction proteins, leading to increased permeability and the translocation of endotoxins like lipopolysaccharides (LPS) into the bloodstream. This process, known as metabolic endotoxemia, alters gut microbiome composition and reduces the production of beneficial metabolites such as short-chain fatty acids (SCFAs). The review also discusses the effects of artificial sweeteners on gut microbiota and their potential health implications. Additionally, it highlights the role of the gut-liver axis in the development of nonalcoholic fatty liver disease (NAFLD) and the impact of gut microbiota on brain health through the gut-brain axis. The review underscores the need for further research to understand the complex interactions between diet, gut microbiota, and these axes, particularly in the context of obesity, metabolic disorders, and neurological conditions.