Protein Intake is Inversely Associated with Abdominal Obesity in a Multi-ethnic Population

Abdominal obesity is related to significant morbidity and mortality and differs by ethnicity; however, the relation between diet and abdominal obesity has not been extensively studied. The aim of this study was to evaluate the dietary and lifestyle determinants of abdominal obesity in a multi-ethnic population. We conducted a cross-sectional study among 617 Canadians of Aboriginal, South Asian, Chinese, and European origins, with diet evaluated using validated, culture specific, interviewer-administered FFQs, and abdominal obesity measured as waist-hip ratio (WHR). The mean proportion of energy intake from protein in the diet was 17.4 vs. 15.8% comparing the lowest and highest tertiles of WHR. Energy-adjusted protein substituted for an equivalent amount of carbohydrate was associated with a reduction in WHR (difference in WHR for every g/d increase in protein intake = -0.0005, P = 0.01) after accounting for age, sex, ethnicity, smoking status, BMI, alcohol intake, height, physical activity, and total energy. Fat or total energy were not related to WHR in the same linear regression model. Smoking was positively and physical activity inversely related to WHR in the multivariate model independent of BMI and other potential confounders. Substituting a modest amount of protein for carbohydrate may reduce abdominal obesity in a diverse multi-ethnic population. Smoking was positively related to abdominal obesity after accounting for BMI.