Flavonoids are a class of natural polyphenolic compounds which cannot be synthesized by humans. These substances possess a series of biological properties, acting on biological systems as antioxidants. The purpose of this study was to analyze the properties of certain foods, determining the total flavonoids as well as their antioxidant activity and fat concentration. We evaluated several foods purchased at the local market, with respect to its antioxidant activity, using two experimental models, the discoloration of DPPH˙ radical and ABTS −. Some foods such as pitanga showed antioxidant activity. The lipid content of fatty foods like açaí, cacao and cupuaçú was determined. Other foods, including pitanga, açaí, cacao and cupuaçú, were evaluated for flavonoid content and antioxidant activity using multivariate statistical analysis (PCA) as a statistical tool to evaluate the correlation between these two parameters. As samples with ED50 up to 500 µg/mL show promising antioxidant activity, several Brazilian fruit and vegetables could be consumed to this end, with a good correlation between flavonoid content and antioxidant activity in most samples. The daily dose of different types of food for antioxidant activity has been calculated based on these results.