Limited knowledge currently exists regarding the dynamics of generational shifts in food consumption among adult residents in China. This study aimed to investigate the generational differences in dietary status among different generations of Chinese adult residents aged 20 years and older. Survey participants from four waves (1991, 2000, 2009, and 2018) of the China Health and Nutrition Survey (CHNS) cohort were included in the study (N = 40,704), providing three-day 24 h dietary data. Participants were categorized into six age groups (20–29, 30–39, 40–49, 50–59, 60–69, and ≥70 years old), each corresponding to specific generations (Gen 10, 20, 30, 40, 50, 60, 70, 80, and 90) based on their age at the time of the survey. This study examined generational differences in the intake of cereals, animal-based foods, vegetables, fruits, dairy, energy, and the contribution of macronutrients to energy using chi-square tests and Kruskal–Wallis tests. All analyses were stratified by gender. Our findings revealed that younger generations exhibited lower daily intake of cereals, vegetables, energy, and contribution of carbohydrates to energy, compared to their older counterparts, regardless of gender. Conversely, regardless of male or female, younger generations showed higher daily consumption of animal-based foods, average fruit and dairy intake, fruit and dairy consumption rates, as well as contributions of protein and fat to energy, compared to older generations. The magnitude of generational differences in food consumption varied by age and gender. In addition, cereal and vegetable intake, energy intake, and contribution of carbohydrates to energy declined with age across all generations, while average dairy intake, fruit and dairy consumption rates, and the contribution of fat to energy tended to increase, regardless of gender. In conclusion, generational differences in food consumption were evident among different generations of Chinese adult residents, characterized by an increase in animal-based food intake and the contribution of fat to energy among generations. Attention should be directed towards addressing the eating behavior of younger generations.