Objective: Obesity and its associated chronic diseases are persistent and growing problems in the United States. Dietary fiber can ameliorate risk through several physiological processes, though little research defines fiber types or sources that most efficiently control waistlines. Popular claims argue that wheat and grain fiber source are nutritional culprits for obesity and cardiometabolic risk. Our investigation sought to understand whether higher ratios of grain to fruit and vegetable fiber consumption frequency were associated with increased waist circumference. Design: Cross-sectional analysis, the 2009-2010 National Health and Nutrition Examination Survey. We regressed individuals' waist circumferences on fiber source ratio and relevant covariates. Setting: Nationally representative adults aged 19 to 69 in the U.S. Results: The ratio of grain to fruit and vegetable source did not significantly alter waist circumference when all covariates were controlled (p=0.773). Those of older age (p<.001) and who reported more sedentary activity (p<.001) had significantly larger waist circumference when compared to their counterparts. Males had significantly larger waist circumference than did females (p<.001); Black (p<.01) had larger waist circumference and other race (p<.001) had smaller waist circumference than did non-Hispanic Whites; and college graduates had smaller waist circumference than did high school graduates (p<.01). Conclusions: Significant differences between racial, ethnic, and income categories may be explained by differing health opportunities available to low- and high-SES neighborhoods. The lack of statistical significance in the primary regression suggests that fiber source ratio has no influence on waist circumference, and invites further exploration of fiber source proportions in the diet.