Diet, health, and environment are closely related concepts, and the consumption levels of water-land resources under different dietary patterns are significantly diverse. Figure 1 shows the $WF=\underset{i=1}{\overset{n}{\mathop \sum }}\,\left( V{{W}_{i}}\times C{{Q}_{i}} \right)$relationship between water-land resources consumption under different dietary patterns. Among them, A1 and B are the actual supply and demand relationship, A2 and B are the theoretical supply and demand relationship under the dietary guidelines. We calculated the consumption of water resources and land resources under different patterns separately: 1) Water resources: By using virtual water theory and the WF method proposed, we introduced the virtual water of unit weight food to calculate the water consumption of Chinese urban-rural residents under the actual dietary patterns and the dietary guide patterns, respectively, and then estimated the water resource utilization effect under the evolution of Chinese dietary patterns. 2) Land resources: On the basis of the method of LRF suggested by Kastner and Nonhebel (2010), we introduced the conversion rate of crop to food, the conversion coefficient of grains to animal-based food, the yield per unit area, the multiple-cropping index and other data to calculate the land resources consumption of urban and rural residents in China in the past 33 years under the actual dietary patterns and dietary guidelines and thereafter analyzed the land resource utilization effect under the evolution of Chinese dietary patterns.

In this study, the food categories were defined based on the FAO classification, which includes eight categories of food commodities: 1) cereals; 2) vegetables; 3) fruits; 4) oilseeds; 5) sugar; 6) eggs; 7) milk; 8) meat (pork, beef and mutton, and poultry). The per capita food consumption, population data, the yield per unit area and multiple-cropping index of urban and rural households in China from 1987 to 2020 were obtained from the National Bureau of Statistics. The conversion rate of crop to food (Table 1), the conversion coefficient of grains to animal-based food (Table 2), etc. were obtained from the Prices for the National Development and Reform Commission (2020). Virtual water content per unit weight for various categories of food reference to Mekonnen and Hoekstra (2012) about China (Table 3). The balanced dietary structure was based on the Chinese Dietary Guidelines (CNS, 2021) (Table 4). In addition, a few scholars investigated the consumption cost of water and land resources in different years of aquatic products, but these parameters are difficult to quantify; hence, the categories of food commodities in this study do not include aquatic products. Among them, the unit weight products of livestock products such as cattle, sheep and milk needed both a certain amount of land and a certain amount of grassland. This study only calculated the consumed land resources.

From 1987 to 2020, the Chinese dietary patterns gradually changed from “cereal- vegetable-based consumption” to “diversified consumption,” and dietary quality had improved significantly, but high-quality protein intake was far from enough (Figure 2). In particular, the per capita cereal consumption and total cereal consumption of Chinese continued to decline, from 198.4 kg/year and 249.6 Mt/year in 1987 to 126.3 kg/year and 161.8 Mt/year in 2020, respectively. The per capita cereal consumption decreased by 36.3%, whereas the total cereal consumption decreased by 35.2%, on the basis of a 29.1% increase in population. The per capita consumption of vegetables decreased from 136.3 kg/year in 1987 to 99.5 kg/year in 2020. The per capita consumption of fruits rose 1.6 times from 19.4 kg/year in 1987 to 50.0 kg/year in 2020. The per capita consumption of oilseeds rose from 4.5 kg/year in 1987 to 9.9 kg/year in 2020. The per capita consumption of sugar decreased from 2.1 kg/year in 1987 to 1.3 kg/year. The per capita consumption of eggs increased from 3.9 kg/year in 1987 to 12.7 kg/year in 2020, which was 3.3 times higher than in 1987, but it was still below the minimum intake in dietary guidelines. The per capita consumption of milk increased from 1.9 kg/year in 1987 to 12.1 kg/year, only 11.1% of the milk intake in the dietary guidelines. The per capita consumption of meat increased from 22.5 kg/year in 1987 to 61.1 kg/year in 2020, and the research period increased to 2.7 times in 33 years. The results were basically consistent with the research of Xin (2021). Overall, the consumption of plant-based foods continued to decrease, while the animal-based food continued to grow. From a global perspective, meat consumption increased with the growth of per capita income. As countries turned from poverty to prosperity, diets gradually shifted towards meat- and protein-rich structures, which led to low cereal demand and high animal-based food demand.

According to the difference of Chinese urban-rural dietary patterns, urban residents’ dietary structure tended to be diversified steadily and rural residents’ dietary structure had been greatly improved, but the imbalance between urban and rural development led to significant differences in the total dietary demand between urban and rural residents in China (CNS, 2021). During the 30 years of the study period, with the rapid development of economy and the continuous advancement of urbanization, income had increased substantially and a large number of people had flowed from rural areas to urban areas, which had led to the rapid growth of urban residents’ food consumption and the continuous decline of rural residents’ food consumption. In addition, the per capita and the total consumption of animal-based food in urban-rural residents showed a rapid increase trend from 1987 to 2020, but the intake of animal-based food and fruits in rural residents was far lower than that of urban residents, and the cereal consumption was much higher than that of urban residents, resulting in the insufficient intake of nutrients such as vitamins and high-quality proteins in rural residents. Studies had shown that the incidence of vitamin A deficiency in rural residents was always higher than that in urban residents (CNS, 2021). Therefore, on the basis of following the principle of dietary balance in China, much attention should be paid to the dietary patterns of residents in rural areas. In particular, in underdeveloped areas, the consumption of animal-based food should be increased and the consumption proportion of animal-based food should be optimized. We should promote urban residents to reduce the consumption of animal-based food and oilseeds and solve the practical problems of urban residents’ overnutrition.

To further explore the utilization effect of water-land resources under the evolution of Chinese dietary patterns, we calculated the theoretical demand of water-land resources based on the Chinese Dietary Guidelines 2021, and the results were compared with the actual consumption of water-land resources in results of the previous section (Table 5). The findings showed that the theoretical demand for water resources of China increased from 674.9 to 871.9 Gm³ between 1987 and 2020, while the theoretical demand for land resources increased from 132.1 to 170.7 Mha. In fact, from 1987 to 2020, the actual consumption of water resources for food consumption in China increased from 471.2 to 848.8 Gm³, while the land resources increased from 88.8 to 129.9 Mha. Furthermore, the actual consumption of water-land resources in urban and rural areas from 1987 to 2020 was lower than the theoretical demand of water-land resources under the balanced diet.

Subsequently, to evaluate the consumption of water-land resources of various categories of food comprehensively, we took the consumption of water-land resources under the nutritional goal as a benchmark to calculate the overall and eight categories of food waste rate of water-land resources (Figure 5, positive value represented the waste rate, negative value represented the saving rate). The results showed that: 1) Overall, waste was not documented for water-land resource consumption with respect to the food consumption of urban-rural residents in China between 1987 and 2020. However, the consumption of water resources would gradually approach the resource cost under the balanced diet patterns and would eventually break through the critical value and reach the state of resource waste. 2) From the perspective of internal structure. In 1987, the WF (LRF) for cereals of urban-rural residents, oilseeds of urban residents, and meat of urban residents showed different degrees of waste of resources, and the water-land resource waste rate of cereal consumption of rural residents was as high as 118.3%. In 1998, the urban residents had shown high resource waste in oilseeds consumption and meat consumption. With the improvement of people’s living standards, there were also significant resources waste of oilseeds and meat consumption in rural areas in 2009. Notably, the WF (LRF) for cereals of rural residents in the 33 years of the study period was still higher than the cost of water-land resources in the balanced diet, which indicated that rural residents still have high demand for cereals, and that the income level of rural residents in China still has greater potential for improvement. Besides, from 1987 to 2020, the water-land resources cost of Chinese consumption of vegetables, fruits, sugar, milk and eggs did not exceed the balanced dietary patterns. In the future, China should actively adjust the dietary patterns, reduce the consumption of oilseeds and meat, and advocate for residents to eat more vegetables, fruits, and high-quality proteins to achieve the sustainable development goal of minimized utilization of water-land resources for food supply as a means of meeting the nutritional needs of residents.

Knowing how to deal with the relationship between the evolution of dietary patterns and the utilization of agricultural water-land resources scientifically is the key to ensuring national food safety and regional sustainable development. In contrast to other studies, we discussed the evolution characteristics of Chinese dietary patterns for 30 years, from 1987 to 2020. Based on dietary balance patterns, this study comprehensively analyzed the utilization effect of water-land resources on food consumption in China, which provided a scientific basis for sustainable food consumption.

From 1987 to 2020, the Chinese dietary patterns gradually changed from cereal-vegetable-based consumption to diversified consumption and meat consumption improved significantly. The global average per capita meat consumption and the total amount consumed is rising, driven by increasing average individual incomes and population growth (Xu et al., 2021). Growth rates varied across different regions, with consumption in high-income countries (the USA and European countries) static or declining and in middle-income countries (India, China) moderately to enormously increasing. In contrast, meat consumption in low-income countries (African countries) was, on average, low and stable (Godfray et al., 2018). Global poultry and pork consumption growth were particularly pronounced in China, too. A well-established empirical relationship known as Bennett’s law showed that as people become wealthier, their diets changed from being primarily based on starchy staples to diets that incorporate increasing amounts of refined grains, fruits, vegetables, meat, and milk. According to the forecast, five billion people (nearly two-thirds of the global population) will become middle class in 2030. Almost all the growth in the number of intermediate classes will occur in Asia (AASSA, 2018). Demand for high-value foods such as meat, dairy, and eggs will continue to increase from an expanding middle class. FAO predicted that the total meat consumption would increase by 76% in the middle of this century compared with 2005 (Tilman et al., 2011).

Moreover, meat is a resource-intensive product, and its production efficiency depends on natural resources (water, land, etc.) sustainable supply, hence the problems related to global sustainable consumption. Uncertainties such as socio-economic changes, COVID-19, trade frictions, natural disasters, etc., may affect these forecasts, especially the exact relationship between meat demand and income growth and food culture in different geographic regions. Moreover, dietary guidelines are a dynamic system, and they are also changing with the continuous progress of social and economic development and cognition. For example, the previous nutritional guidelines in the United States emphasized the income of meat and milk in contrast to the increase in the incidence of malignant diseases, but the situation is slowly changing. In recent years, the United States Dietary Guidelines have also advocated more intake of fresh fruits and vegetables. However, the transformation process is complicated, and the political and economic barriers are plenty, including the mighty meat and dairy industries (Stoll-Kleemann and O’Riordan, 2015; Delabre et al., 2021). Overall, researchers generally believe that meat consumption growth occurs mainly in low- and middle-income countries, especially in China, an emerging economy experiencing rapid shifts in food consumption patterns (HLPE, 2020). Therefore, an essential and challenging task is to clarify how the dietary patterns of residents in different regions evolve.

In contrast to the balanced diet patterns, there was no waste of water-land resource consumption for the food consumption of urban-rural residents in China between 1987 and 2020. However, the consumption of water resources would gradually approach the resource cost under the balanced diet patterns. It would eventually break through the critical value and reach the state of resource waste. As a country with a shortage of agricultural resources, approximately 35% of China’s land is severely degraded, and only 7% is suitable for food crops. China’s per capita cultivated land resources are less than half the global average. Still, the current food consumption of cultivated land has exceeded domestic supply and has become the world’s largest net importer of virtual cultivated land in recent years (Liang et al., 2022). By 2050, the global population is expected to reach 9.8 billion people. The need for global crops will increase by 100% to 110% compared with the data in 2005 (Tilman et al., 2011), which requires improved agricultural land or productivity. However, the productivity increases have not kept up with increasing demand, suggesting that the continued expansion of agricultural land is inevitable. As the world’s largest net importer of virtual cultivated land, China’s cultivated land had minimal space for food production and a severe shortage of national reserve land resources (Wang and Li, 2021). Survey data in 2017 showed that the total area of national reserve land resources was 5350 thousand hectares, of which only 627 thousand were concentrated and contiguous (Zheng et al., 2022). Therefore, the supply of cultivated land resources for food consumption will become an essential bottleneck in China’s food security. It is imperative to alleviate the pressure on agricultural resources by adjusting the food consumption patterns. In addition, global water competition is intensifying, with approximately 1 billion people in Asia likely to face water shortages over the next 35 years (AASSA, 2018). However, as a populous country with per capita water resources less than one-fourth of the global average level, China’s overall agricultural water resource utilization efficiency is low.

The effective utilization coefficient of China’s cultivated land irrigation water in 2020 was only 0.565, and the country is still lagging compared with the level of 0.7-0.8 in developed countries. Furthermore, the irrigation water output per unit is still far behind that of developed agricultural countries (Zheng et al., 2022). Compared with the balanced diet, the resource waste rate of meat consumption of Chinese in 2020 was as high as 134.1%, and the resource waste rate of meat consumption of urban residents increased by 142.3% compared with that in 1987. Meat production will need conversions of natural habitats to grassland and grazing and conversion to cultivated land to produce grain and soya for livestock consumption. The WF of meat production is more than three times that of plant-based food. In the High Plains aquifer in the central United States, where increasing production of cattle fed with irrigated corn resulted in severe aquifer depletion (Steward et al., 2013). Changes in global meat consumption in the future will have a significant impact on water-land resources and ecological and environmental systems. A world that can provide 10 billion or more people with the amount of meat currently consumed by most high-income countries without having a significant negative impact on resource and environmental sustainability is difficult to imagine. Therefore, an urgent task is to comprehensively analyze China’s water-land resource utilization effects on food consumption.

We believe that the relationship between dietary patterns and water-land resource utilization should be examined from multiple dimensions in the future, focusing on the discussion from a “system perspective-global perspective-regional perspective-resource perspective,” as follows: 1) From a system perspective, we can incorporate the existing researches about diet and resources into the “food system.” A food system is an “open and complex giant system” composed of subsystems such as food production, processing, circulation, consumption, and waste disposal; it is influenced by factors such as resources, capital, technology, culture, and institutions. On the one hand, the food system is related to the utilization of agricultural water-land resources, and on the other hand, it affects human consumption and health. Exploring the organic connection between the multiple elements of the food system behind the evolution of residents’ dietary patterns entails far-reaching significance for sustainable food consumption. 2) From a global perspective, trade in agricultural products is a virtual transfer of water-land resources. Under the new patterns, we should organically combine food security with building a human community with a shared future. To make a system of high-quality agricultural development and sustainable utilization of water-land resources in China, we should scientifically coordinate the balance between domestic and international imports and comprehensively adjust the residents’ dietary patterns. 3) From a regional perspective, as the essential medium of the human-land relationship, the relationship between food consumption and resource utilization is a typical geographical issue that focuses on showing humans’ demand for land and land supply to humans. In the future, we can explain the evolution of dietary patterns from the aspects of planting structure, mode of production, and spatial allocation of water-land resources in different regions of China, and the geographical practices of the agricultural output should be scientifically delineated. 4) From the perspective of resources, water resources and land resources include multiple attributes (quantity, quality, ecology, space, and time) with multiple values (economic output, social security, food security, and ecological security. We need to establish a “comprehensive elements” value realization approach and a long-term compensation mechanism and promote the sustainable use of agricultural water-land resources and national food security by division and classification. The above discussion provides many research topics for the future, for example, knowing how to promote the ecologically sustainable development of resources and reduce the environmental and ecological costs of food security while ensuring food security. In relation, learning how to ensure food security while maintaining other services for ecosystem safety. In addition, we can solve the contradiction between upgrading dietary consumption and water-land resources from the perspective of “Production-Living-Ecological-Life” space (Figure 6). We can use National Land and Space Planning to co-ordinate the land-ocean food system, adjust the planting structure with the help of Multifunctional Agricultural Production Areas, and regulate and control different levels of stakeholders from the international market, government, agricultural management, and individuals and families.

However, this study also has certain limitations. One limitation is related to the virtual water, which selected in this study does not consider the difference in time. Second, because few studies mention the virtual water content of aquatic products, and the land demand for aquatic products is difficult to quantify, this study does not include aquatic products in the dietary structure for discussion. Another limitation is that this study mainly estimates the land demand for animal-based food consumption through the ratio of feed to meat, and does not discuss the land use of grassland, which needs to be further discussed and analyzed in future research. Fourth, related research indicated that the average daily demand for food nutrition in China showed a downward trend, which reflected the aging problem of China’s population. Therefore, nutrition security further extends China’s food security research. In the future, we should gradually shift the quantitative analysis about weight form to the equilibrium research under nutrition.

Water-land resources are the key factors to ensure the sustainable development of food consumption of Chinese. Therefore, knowing how to minimize the utilization of water-land resources in food supply to meet the nutrition demand has become a significant subject of sustainable consumption. Our study focused on the analysis of changes in WFs and LRFs under the evolution of Chinese dietary patterns in the 33 years from 1987 to 2020, and discussed the utilization effect of water and land resources from the perspective of nutrition balance. The results showed that the Chinese dietary patterns gradually changed from cereal-vegetable-based consumption to diversified consumption, and the imbalance between urban and rural development led to significant differences in the total dietary demand between urban and rural residents in China. From 1987 to 2020, the LRF and the total LRF in China showed an upward trend, the changes in LRF and WF in China were basically consistent, which indicated that the evolution of dietary patterns had overall consistency with the WF and LRF. In contrast to the balanced diet patterns, waste was not documented for water-land resource consumption with respect to the food consumption of urban-rural residents in China between 1987 and 2020. However, the consumption of water resources would gradually approach the resource cost under the balanced diet patterns and would eventually break through the critical value and reach the state of resource waste. Notably, the WF (LRF) for cereals of rural residents in the 33 years of the study period was still higher than the cost of water-land resources in the balanced diet, which indicated that rural residents still have high demand for cereals, and that the income level of rural residents in China still has greater potential for improvement. Besides, from 1987 to 2020, the water-land resources cost of Chinese consumption of vegetables, fruits, sugar, milk and eggs did not exceed the balanced dietary patterns. Therefore, on the basis of following the principle of dietary balance in China, much attention should be paid to the dietary patterns of residents in rural areas. In particular, in underdeveloped areas, the consumption of animal-based food should be increased and the consumption proportion of animal-based food should be optimized. We should promote urban residents to reduce the consumption of animal-based food and oilseeds and solve the practical problems of urban residents’ overnutrition. Furthermore, all Chinese residents should be encouraged to consume more vegetables, fruits and high-quality protein.