This systematic review and analysis examine the role of food prices and diet cost in socioeconomic disparities in diet quality and health. The review finds that healthier diets generally cost more than unhealthy ones, which contributes to social inequalities in diet quality and health. Lower-income groups tend to choose cheaper, lower-quality foods, often with higher energy density and lower nutritional value. Nutrient-rich foods, while available at low cost, may not be palatable or culturally acceptable to low-income consumers. Acceptable healthier diets are typically more expensive, and food budgets in poverty are insufficient to ensure optimal diets. The review highlights that the higher cost of healthy diets is a key factor in socioeconomic disparities in diet quality. Identifying affordable, nutrient-rich, and culturally acceptable food patterns is crucial to reducing these inequalities. The analysis also shows that food prices and dietary choices are closely linked, with lower-income groups often facing greater financial barriers to accessing healthier foods. Studies indicate that energy-dense, low-nutrient foods are cheaper per calorie, while nutrient-rich foods are more expensive. This cost difference influences dietary choices, with lower-income groups often opting for cheaper, less nutritious options. The review also discusses the limitations of cross-sectional studies in establishing causality and emphasizes the importance of longitudinal studies. It highlights that food prices and dietary patterns are influenced by various factors, including cultural preferences, availability, and preparation methods. The analysis shows that lower-income groups often have limited access to affordable, nutritious foods, leading to poorer diet quality and health outcomes. The review concludes that addressing socioeconomic disparities in diet quality requires not only improving access to healthy foods but also promoting affordable, culturally acceptable, and nutritious food patterns.This systematic review and analysis examine the role of food prices and diet cost in socioeconomic disparities in diet quality and health. The review finds that healthier diets generally cost more than unhealthy ones, which contributes to social inequalities in diet quality and health. Lower-income groups tend to choose cheaper, lower-quality foods, often with higher energy density and lower nutritional value. Nutrient-rich foods, while available at low cost, may not be palatable or culturally acceptable to low-income consumers. Acceptable healthier diets are typically more expensive, and food budgets in poverty are insufficient to ensure optimal diets. The review highlights that the higher cost of healthy diets is a key factor in socioeconomic disparities in diet quality. Identifying affordable, nutrient-rich, and culturally acceptable food patterns is crucial to reducing these inequalities. The analysis also shows that food prices and dietary choices are closely linked, with lower-income groups often facing greater financial barriers to accessing healthier foods. Studies indicate that energy-dense, low-nutrient foods are cheaper per calorie, while nutrient-rich foods are more expensive. This cost difference influences dietary choices, with lower-income groups often opting for cheaper, less nutritious options. The review also discusses the limitations of cross-sectional studies in establishing causality and emphasizes the importance of longitudinal studies. It highlights that food prices and dietary patterns are influenced by various factors, including cultural preferences, availability, and preparation methods. The analysis shows that lower-income groups often have limited access to affordable, nutritious foods, leading to poorer diet quality and health outcomes. The review concludes that addressing socioeconomic disparities in diet quality requires not only improving access to healthy foods but also promoting affordable, culturally acceptable, and nutritious food patterns.