Trends in dietary carbohydrates, protein and fat intake and diet quality among Chinese adults, 1991-2015: results from the China Health and Nutrition Survey

Objective: Dietary transitions in China have undergone rapid changes in over the last three decades. The purpose of this study is to describe trends in the macronutrient consumption, the sources of those nutrients and the diet quality among Chinese adults. Design: Longitudinal China Health and Nutrition Survey (CHNS) cohort analysis. Main outcomes are dietary energy intake from total carbohydrate, protein and fat and their subtypes, as well as food sources of carbohydrates, protein, and fat, and the China Dietary Guidelines Index 2018 (CDGI-2018). Setting: CHNS (1991, 2000, 2009 and 2015). Participants: Data from the longitudinal 1991, 2000, 2009 and 2015 CHNS of adults aged 18 years or older who had complete demographic information. Results: The estimated mean energy intake from total carbohydrate decreased from 62 center dot 6 % to 50 center dot 6 % between 1991 and 2015, while the mean energy intake from total protein increased from 12 center dot 6 % to just 13 center dot 1 % and the mean energy intake from total fat significantly increased from 24 center dot 0 % to 35 center dot 8 % (P < 0 center dot 001 for trend). Decreases were observed in evaluated mean energy from low-quality carbohydrates (from 53 center dot 6 % to 41 center dot 7 %) and incomplete protein (from 9 center dot 3 % to 7 center dot 5 %), while increases were seen in estimated mean energy from high-quality protein (from 3 center dot 3 % to 5 center dot 5 %), high-quality fat (from 9 center dot 1 % to 16 center dot 7 %) and low-quality fat (from 14 center dot 9 % to 19 center dot 0 %). Low-quality carbohydrates, primarily those derived from refined grains, decreased from 52 center dot 2 % to 36 center dot 2 %. The diet quality as measured by CDGI-2018 improved, with the estimated mean increasing from 41 center dot 7 to 52 center dot 4 (P < 0 center dot 01 for trend). Conclusion: For Chinese adults, there was a significant change in the macronutrient composition over the previous few decades. The percentage of energy consumed from carbohydrates significantly decreased; however, the percentage of energy consumed from total fat significantly increased. Additionally, the diet quality remains suboptimal.