Tackling the global burden of acute malnutrition in children remains a major public health challenge and is essential for achieving sustainable development. Despite having effective treatment options, most wasted children go untreated; treatment coverage for severe acute malnutrition (SAM) children is only about 20%. Milk is currently an essential component of effective SAM treatment, incorporated into ready-to-use therapeutic food (RUTF). Reaching the untreated children, as well as preventing SAM, requires investment in innovative and cost-efficient approaches. To date, attempts to replace or remove milk from RUTF have been either unsuccessful or unpersuasive. This is likely because milk provides the highest protein quality and density of all typical RUTF ingredients. However, alternative protein sources could provide cost savings. Alternative protein sources, especially plant-based protein alternatives, have had shown more promising progress for the treatment of children with moderate acute malnutrition. Acknowledging that cost is a major barrier to the scale-up of treatment of acute malnutrition and that alternative protein sources are a practical means to reduce cost, continued research focusing on alternative proteins is necessary.