How Does Energy Intake Change in China? A Life Cycle Perspective

China's population is showing the characteristics of "fewer children" and "aging", which will have a long-term and far-reaching impact on the food and nutritional needs of China and the world. In this paper, adult equivalent scale (AES) variables representing the household population structure were introduced into the energy intake model to quantify the impact of population structure changes on energy intake and reveal the characteristics of energy intake changes in the life cycle of Chinese residents. It is found that the change in the population structure has a significant impact on the energy intake of urban households in China, and the elasticity is 0.446. The energy intake of Chinese elderly over the age of 60 shows a trend of first increasing and then decreasing, especially after the age of 65, which indicates that the aging will promote a decline in food consumption in China. The energy intake of 1-10-year-old children, 22-30 year old, and 40-45 year old women all showed a change of first a decrease and then an increase, which may be related to parents' care for young children and women with children's management of body size. The average household size expressed by the adult equivalent scales of energy consumption is 2.341, which is smaller than the 3.052 calculated by the population number. The conclusion indicates that the prediction of the food and nutritional demand should be adjusted according to the changes and differences in accordance with the intensification of "fewer children" and "aging", as well as the life cycle changes in residents' energy intake, which is conducive to the formulation of food and nutrition security policies.