Application of the ≤ 10:1 carbohydrate to fiber ratio to identify healthy grain foods and its association with cardiometabolic risk factors

Optimal metrics to assess healthfulness of carbohydrate-rich products are not well established. We investigated how the content per 10 g of carbohydrate of at least 1 g of fiber (≤ 10:1-ratio) related to nutritional quality in grain foods as well as cardiometabolic risk factors in Sao Paulo, Brazil. Data were from the cross-sectional population-based study 2015 Health Survey of Sao Paulo, including a probabilistic sample of urban residents in the city. Participants (n = 1188) aged 20 + years completed a 24-h dietary recall and a subsample of 603 participants had blood samples, anthropometrics, and blood pressure measurements collected, and answered a second 24-h recall. Energy and nutrient contents of grain foods meeting or not meeting the ≤ 10:1-ratio were evaluated using linear regression models. The association between consumption (percent energy, %E) of grain foods meeting the ≤ 10:1-ratio and cardiometabolic risk factors were investigated using linear regression models. Foods meeting the ≤ 10:1-ratio had less available carbohydrate (− 3.0 g/serving), total sugar (− 7.4 g/serving), added sugar (− 7.2 g/serving) and saturated fat (− 0.7 g/serving), and more dietary fiber (+ 3.5 g/serving), protein (+ 2.1 g/serving), potassium (+ 100.1 mg/serving), iron (+ 0.9 mg/serving), selenium (+ 4.2 µg/serving), magnesium (+ 38.7 mg/serving), and zinc (+ 1.1 mg/serving). Each increase in 1%E consumption of grain foods meeting the ≤ 10:1-ratio was associated with lower levels of blood triacylglycerol (− 10.7%), the triacylglycerol/high-density lipoprotein cholesterol ratio (− 14.9%), fasting insulin (− 13.6%), and homeostasis model assessment for insulin resistance (− 14.0%). The ≤ 10:1-ratio identified grain foods with higher nutritional quality and higher intakes of these foods were associated with cardiometabolic risk factors related to atherogenic dyslipidemia and insulin resistance.