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 62·6 % to 50·6 % between 1991 and 2015, while the mean energy intake from total protein increased from 12·6 % to just 13·1 % and the mean energy intake from total fat significantly increased from 24·0 % to 35·8 % (P < 0·001 for trend). Decreases were observed in evaluated mean energy from low-quality carbohydrates (from 53·6 % to 41·7 %) and incomplete protein (from 9·3 % to 7·5 %), while increases were seen in estimated mean energy from high-quality protein (from 3·3 % to 5·5 %), high-quality fat (from 9·1 % to 16·7 %) and low-quality fat (from 14·9 % to 19·0 %). Low-quality carbohydrates, primarily those derived from refined grains, decreased from 52·2 % to 36·2 %. The diet quality as measured by CDGI-2018 improved, with the estimated mean increasing from 41·7 to 52·4 (P < 0·01 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.