[Main food intake prediction of Chinese residents based on grey model]

To predict the main food intake trend of the China's urban and rural residents from 2022 to 2030.

Data was collected from the China Health and Nutrition Survey(CHNS), which was carried out on a stratified, multistage, clustered, and random sampling method. And the average daily food intake in the survey was continuously collected by a 24-hour dietary review method for 3 consecutive days. The sample sizes aged 20 years or older of seven rounds survey were 9794, 9425, 9313, 9726, 12 760, 15 446 and 15 051, respectively. Based on the seven rounds of average food intake, the main food intake of urban and rural residents in China from 2022 to 2030 was predicted by the Grey model.

(1)The mean absolute percentage error of average food intake prediction in urban and rural ranged from 1.6% to 38.4%. (2)In terms of the trends of food intake from 2022 to 2030, the grain and vegetable average intake of plant food in urban and rural residents showed a decreasing trend, while the average intake of fruits showed an increasing trend. The average intake of animal food, such as poultry and aquatic products in urban, livestock, poultry, eggs in rural areas showed an upward trend. Meanwhile, the average intake of animal food, such as livestock and eggs in urban and aquatic products in rural showed a downward trend. (3)Compared with the 2018, the fruits, poultry and aquatic product intake of urban and rural residents in 2030 will increase by 60.7%, 29.4% and 6.6%, the intake of grain, vegetables, livestock and eggs in urban areas will decrease by 36.9%, 19.4%, 8.7% and 12.4%, respectively. In 2030, the intake of fruits, livestock, poultry and eggs of rural residents will increase by 88.9%, 31.8%, 71.9% and 9.2%, respectively. While the intake of grain, vegetables and aquatic products of rural residents will decrease by 32.5%, 24.8% and 2.2%, respectively. (4)By 2030, the average intake of poultry in urban and rural areas will be within the recommended range of dietary guidelines. But the average intake of grain, vegetables, fruits, eggs and aquatic products in urban and rural areas will remain below dietary recommendations. While the livestock average intake will be far higher than the recommendations.

The model accuracy is different when applied to different kinds of food. According to the prediction result of the grey model, residents should be guided to maintain the current grain intake level and increase the intake of vegetables, fruits, poultry, eggs and aquatic products in order to get balanced diet, while reducing the intake of livestock.