Carbohydrate Intake and Dietary Fiber Ratio as Diagnostic Tool for Diet Quality and Prognostics of Insulin Resistance in Brazilian Free-living Adults

In major food-questionnaires the consumption of refined products (sugars and/or cereals) and whole grains are computed as total carbohydrate (CHO). Therefore, CHO to fiber ratio would be a correcting tool offering an indirect way to discriminate the actual risk of a high glycemic meal. This study aimed first to identify the CHO to fiber ratio in free-living adults and, secondly verify its relationship with the presence of either Metabolic Syndrome (MetS) and/or insulin resistance. Cross sectional study with 600 subjects (54.6 ± 11yrs) enrolled from an ongoing dynamic cohort study. Diet quality (Health Eating Index-HEI) and food intake were correlated with gender, age, anthropometry, plasma biochemistry, blood pressure and presence of MetS (ATP III-NCEP) and insulin resistance (HOMA-IR). Data on CHO to Fiber ratio were divided into quartiles. CHO to Fiber ratio showed a significant positive association with the daily servings of sugar and cereals, and a negative association with servings of legumes and HEI. When adjusted by age, gender, BMI and kcal/day, the lower quartile (Q1) of CHO to fiber ratio was discriminated by the fewer servings of sugar, higher servings of legumes and higher HEI score. Moreover, Q1 showed lower HOMA-IR than any other quartiles; however, without any significant relationship with the presence of MetS and neither with its components. Dietary CHO to fiber ratio associates strongly with insulin resistance (HOMA-IR) but weakly with altered glycemia. Thus, CHO to fiber ratio may be a useful, single, handful and costless dietary tool for diagnosing poor quality CHO-diets and insulin resistance risks.