A serving of filet mignon is typically 3 oz., so eating an 8-oz. serving, with 558 calories and nearly 41 g of fat, with 16 g being saturated, may be overdoing it. In addition, a diet that is too high in fat and calories can result in weight gain. Meat is an important source of iron, and 8 oz. of filet mignon contains just over 3 mg. The daily intake recommendation for iron is 8 mg per day for men and 18 mg daily for women. Iron aids in transporting oxygen through your blood and plays a role in cell growth.