Ready-to-use therapeutic foods (RUTFs) are solid foods that were developed by changing the formulation of the existing liquid diet, F-100, recommended by the World Health Organization (WHO) for the rapid catch-up phase of the treatment of children suffering from severe acute malnutrition (SAM). The resulting products proved highly effective in promoting weight gain in both severely and moderately wasted children and adults, including those infected with HIV. The formulation of the existing RUTFs, however, has never been optimized to maximize linear growth, vitamin and mineral status, and functional outcomes. The high milk content of RUTFs makes it an expensive product, and using lower quantities of milk seems desirable. However, the formulation of alternative, less expensive but more effective versions of RUTF faces difficult challenges, as there are uncertainties regarding the effect in terms of protein quality, antinutrient content, and flatulence factors that will result from the replacement of current dairy ingredients by less expensive protein-rich ingredients. The formulation of alternative RUTFs will require further research on these aspects, followed by efficacy studies comparing the future RUTFs to the existing formulations.