The independent associations of protein consumption with body fat and glycaemic control in adult Chinese

Purpose: High-protein diets were popular in weight control. However, the role of protein intake in adiposity and related metabolic conditions among general populations is not clear. We aimed to evaluate the associations of protein intake with adiposity and glycaemic control among adult Chinese in a nationwide population-based survey. Methods: The data were from China Health and Nutrition Survey 2009. A total of 9360 men and women aged 18 years or older were included. Body fat percentage was calculated using validated Chinese-specific equations. Dietary intake levels of macronutrients were evaluated by food-weighing approach combined with a 3-day food intake recall. Results: Averagely, our participants have 12.5% energy intake from dietary protein. With multivariate adjustment including total energy intake, the odds ratios (95% CIs) of excessive adiposity (body fat percentage ≥ 20/30% for men/women), and central obesity (waist circumference ≥ 90/80 cm for men/women) were 1.51 (1.30, 1.75) and 1.40 (1.21, 1.62), respectively, comparing extreme quintiles of relative protein intake, while fat and carbohydrate were not associated with adiposity indices. Moreover, higher relative protein intake was associated with elevated concentration of fasting glucose (β ± SE: 1.233 ± 0.583), fasting insulin (23.211 ± 9.191), glycated hemoglobin (1.057 ± 0.369), and insulin resistance indicated by homeostasis model assessment of insulin resistance (7.558 ± 2.928) (all P < 0.05). Further adjusting for body mass index attenuated the associations. Conclusion: In Chinese adults, higher habitual protein consumption may be associated with higher adiposity and worse glycaemic control, independent of total energy intake.