The lack of dietary fiber may be a contributing factor in obesity. This study examined the fiber intake of three weight groups: normal (20.0 < or = BMI < or = 27.0), moderately obese (27.1 < or = BMI < or = 39.9) and severely obese (BMI > or = 40.0). Each group contained 50 subjects. Detailed 3-day food records were used to gather the nutritional data. Fiber intake in the normal weight group was 18.8 +/- 9.3 grams, the moderately obese consumed 13.3 +/- 5.8 grams of fiber and the severely obese 13.7 +/- 5.7 grams. Total fiber intake in grams was found to be significantly higher in the lean group (p < 0.05) and was positively associated with sex and education level with men and more highly educated individuals consuming more fiber. Using regression analysis total fiber in grams and fiber in g/1000 kcalories was inversely associated with BMI after adjusting for sex, age, education level and income (p < 0.01). A high fiber diet may help to promote a negative energy balance by causing early satiety secondary to gastric distention. Dietitians and physicians need to emphasize the importance of a high fiber diet to their obese patients.