Medical Foods Equity Act of 2013 - Amends titles XVIII (Medicare), XIX (Medicaid), and XXI (Children's Health Insurance) (CHIP) of the Social Security Act to provide coverage of medically necessary food and food modified to be low protein formulated to be consumed or administered under the supervision of a qualified medical provider, for the treatment of conditions as recommended by the Advisory Committee on Heritable Disorders in Newborns and Children (the Advisory Committee), and the medical equipment and supplies necessary to administer such food. Provides coverage under the Department of Defense (DOD) TRICARE and Federal Employees Health Benefits (FEHBP) programs for such health benefits.

Defines "medically necessary food" as a food formulated to be consumed or administered through the gastrointestinal tract orally or by tube under the supervision of a physician and intended for the specific dietary management of a disease or condition for which distinctive nutritional requirements, based on recognized scientific principles, are established by medical evaluation. Includes nutritionally modified counterparts of traditional foods and other forms of foods such as formulas, pills, capsules, and bars.

Provides Medicare, Medicaid, and CHIP prescription drug coverage of pharmacological doses of vitamins and amino acids used for the treatment of inborn errors of metabolism, for the treatment of conditions as recommended by the Advisory Committee, and as prescribed by a qualified medical provider. Provides similar coverage of such items under the TRICARE and FEHBP programs, without regard to the age of the patient.