Global Malnutrition Prevention and Treatment Act of 2021 This act sets out programs and otherwise directs the U.S. Agency for International Development (USAID) to carry out activities to prevent and treat malnutrition globally. Specifically, USAID may leverage resources to address malnutrition through the Global Nutrition Coordination Plan (an interagency effort to strengthen the impact of U.S. investments in nutrition) and its role on the board of directors of the U.S. International Development Finance Corporation. USAID must also select countries based on specified malnutrition-related indicators for purposes of targeting malnutrition prevention and treatment programs and update the selection within five years. Additionally, USAID may establish the Nutrition Leadership Council to coordinate federal government activities to prevent and treat malnutrition; and target resources and nutrition interventions to the populations most susceptible to severe malnutrition and otherwise support efforts to prevent and treat malnutrition globally. The act also requires USAID to provide to Congress an implementation plan and annual reports concerning its programs for treating and preventing malnutrition. The act's provisions terminate seven years after its enactment.