Based on a lower reported incidence of breast cancer in the Arab population in Israel, nutritional levels were evaluated in a case-control study of 33 Jewish and 10 Arab patients with breast cancer all matched with a first-degree family-related control. Demographic, gynecologic, obstetric, anthropometric, genetically tumor-related, and nutritional data were ascertained through interviews, tests, and questionnaires. Food consumption, calories, protein, fat, and fiber intake, and anthropomorphic measures were calculated. The following results were obtained:1.Calories of food consumption were significantly higher in Jewish and Arab patients than in their controls.2.Jewish patients consumed significantly higher levels of monounsaturated fat; Arab patients consumed significantly higher levels of dietary fiber.3. Animal protein intake was elevated in patients of both ethnic origins as compared with controls.4. Vegetable fat and monounsaturated fatty acids were elevated in Arab patients as compared with Jewish patients.5. Body weight of both Arab and Jewish patients was not significantly higher when compared with their controls.6. Energy consumption and obesity were higher in breast cancer patients than in the controls. This supporting evidence suggests an association between obesity and breast cancer occurrence.