The etiology of abdominal obesity is multifactorial and has environmental factors as its most expressive risk factors. This study cross-sectional analyzed the association of abdominal fatness with physical inactivity and food inadequacy of 1,557 subjects, both genders, over 35yrs. old, enrolled in an ongoing epidemiological study. Waist circumference (WC) was the primary variable and demographic, social-economic, anthropometric and dietary intake data, were the co-variables.NCEP-ATP III, WHO, IPAQ-long (version 8) and Healthy Eating Index were used for functional definition of variables. Furthermore, longitudinal data from 50 subjects in an exercise protocol for 10 week receiving either regular diet (G1, n=22) or 30g fiber adequacy (G2; =28), were analyzed. The performed statistical analyses used software SAS for Windows, version 9.1 with p=0.05. In a predominantly female sample (74%), 76% aging 35-60yrs, 64% completed elementary school, 73% were living in a low income household, 77.5% overweight. The 62.5% presenting altered WC values were predominantly older, presented higher body fatness, and were consuming low variety-poor quality diet rich in fat (mainly saturated) and lower in fruit. WC correlated negatively with fruit intake and aerobic capacity (VO2max) but only carbohydrate (positive) and fruit intake (negative) were considered independent risk factors for abdominal obesity. In the longitudinal study, both G1 and G2 groups were similar at baseline and G1 maintained the anthropometry values throughout the experiment. Conversely, G2 decreased total body (4%) and WC (7%) fatness, reducing severe obesity by 16%, minimally affecting overweight and eutrophic rates. G2 presented 211% increase in fiber intake and 150% increase in plasma beta-carotene (colorful-fiber marker). Thus, in conclusion, recommended dietary fiber intake (increased fruit and low CHO intake) and physical activity would be the recommended changes against abdominal obesity and, by associating both physical exercises and dietary fiber there was indeed a decrease in abdominal fatness and obesity, predominantly at its higher grade.