With rising incomes and urbanization, high-fat and high-sugar diets have replaced traditional dietary patterns exerting, negatively impact on both public health and global environmental costs. To evaluate the rationality of dietary structure and greenhouse gas (GHG) emissions among urban and rural residents in the Yangtze River Economic Belt, this study utilized per capita consumption data of meat, poultry, aquatic products, eggs, dairy, grains, and vegetables provided by the National Bureau of Statistics from 2015 to 2023. Referring to the Dietary Guidelines for Chinese Residents (2022) and GHG emission factors determined by the Food and Agriculture Organization of the United Nations, the characteristics and environmental impact of dietary structure of urban and rural residents in the Yangtze River Economic Belt were analyzed. The results indicated that: (1) From 2015 to 2023, the consumption of plant-based foods remained 3-4 times higher than animal-based foods, through absolute consumption of animal-based foods is rapidly increasing. Among them, the consumption of red meat increased by 34.2% (urban) and 60.3% (rural), respectively. Revealing structural irrationality and insufficient intake level overall. Dairy consumption remained below 15% of the recommended amount in the dietary guidelines. It is recommended to reduce the intake of the red meat and other food, while increasing the intake of low-carbon foods such as eggs, milk, fresh and dried fruits and vegetables. (2) The GHG emissions from the diets of urban and rural residents in the Yangtze River Economic Belt increased from 235.8 and 254.9 kgCO2eq/(a.person) in 2015 to 265.6 and 299.9 kgCO2eq/(a.person) in 2023, respectively. The overall emissions remained below than 1/2 of the recommended carbon budget implied by the “Dietary Guidelines for Chinese Residents (2022)”. To archeive recommended intake levels without technological or behavioral changes would double China's agricultural GHG emissions. Therefore, China's agricultural system faces huge pressure of GHG emissions. (3) During 2015 to 2023, the GHG emissions from grain consumption in the Yangtze River Economic Belt accounted for 43.0%-44.8% (urban) and 53.6%-62.0% (rural) of the total dietary emissions, respectively. The GHG emissions from animal-based foods increased from 86.0 and 62.3 kgCO2eq/(a.person) in 2015 to 111.0 and 105.7 kgCO2eq/(a.person) in 2023, respectively, with an increase of 29.0% and 69.6%. By 2023, grain consumption respectively contributed to accounted 39.3% (urban) and 49.5% (rural) of the overall dietary carbon emissions, and the carbon emissions from red meat consumption accounted for 21.8% and 29.5%, respectively. The results provide critical insights for promoting the health of urban and rural residents in the Yangtze River Economic Belt and reducing the impact of the agricultural system on the global environment.