This review explores the effects of dietary interventions on various diseases, focusing on their potential as adjunctive therapies. Diet, as a critical source of nutrients, significantly influences human health and disease progression. Recent studies have highlighted the therapeutic potential of dietary interventions in cancer, neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions can modulate metabolism, disease trajectory, and therapeutic responses. The review discusses various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet. Each intervention is explored in terms of its immunomodulatory effects, biological impacts, and underlying molecular mechanisms. For instance, calorie restriction can reduce tumor growth and enhance the efficacy of cancer treatments by altering metabolic pathways and immune responses. Fasting-mimicking diets and ketogenic diets can also modulate tumor metabolism and immune function, potentially improving treatment outcomes. The review emphasizes the complex interplay between dietary interventions and disease pathogenesis, highlighting the need for further research to understand the underlying mechanisms. Despite encouraging results, many dietary strategies remain underutilized in disease management due to incomplete understanding of their therapeutic mechanisms. Additionally, the review delves into the metabolic characteristics and nutrient availability in tumors, particularly in the tumor microenvironment (TME). It discusses how dietary interventions can influence the TME, affecting cell metabolism and immune function. For example, glucose metabolism in immune cells and cancer cells plays a crucial role in energy production and immune suppression. Lipid metabolism in Tregs and macrophages also impacts tumor progression and immune tolerance. Finally, the review examines organ-specific metabolic profiles and their dysregulation in cancer, suggesting that targeted therapeutic strategies can be developed by exploiting unique metabolic dependencies of tumors. Overall, the review provides valuable insights into the potential application of dietary interventions as adjunctive therapies in disease management, emphasizing the need for further research to optimize their use in clinical settings.This review explores the effects of dietary interventions on various diseases, focusing on their potential as adjunctive therapies. Diet, as a critical source of nutrients, significantly influences human health and disease progression. Recent studies have highlighted the therapeutic potential of dietary interventions in cancer, neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions can modulate metabolism, disease trajectory, and therapeutic responses. The review discusses various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet. Each intervention is explored in terms of its immunomodulatory effects, biological impacts, and underlying molecular mechanisms. For instance, calorie restriction can reduce tumor growth and enhance the efficacy of cancer treatments by altering metabolic pathways and immune responses. Fasting-mimicking diets and ketogenic diets can also modulate tumor metabolism and immune function, potentially improving treatment outcomes. The review emphasizes the complex interplay between dietary interventions and disease pathogenesis, highlighting the need for further research to understand the underlying mechanisms. Despite encouraging results, many dietary strategies remain underutilized in disease management due to incomplete understanding of their therapeutic mechanisms. Additionally, the review delves into the metabolic characteristics and nutrient availability in tumors, particularly in the tumor microenvironment (TME). It discusses how dietary interventions can influence the TME, affecting cell metabolism and immune function. For example, glucose metabolism in immune cells and cancer cells plays a crucial role in energy production and immune suppression. Lipid metabolism in Tregs and macrophages also impacts tumor progression and immune tolerance. Finally, the review examines organ-specific metabolic profiles and their dysregulation in cancer, suggesting that targeted therapeutic strategies can be developed by exploiting unique metabolic dependencies of tumors. Overall, the review provides valuable insights into the potential application of dietary interventions as adjunctive therapies in disease management, emphasizing the need for further research to optimize their use in clinical settings.