Jeanette Gehrig and colleagues have designed a diet that can help digestive tracts damaged by acute childhood malnutrition develop a mature gut microbial community, necessary for proper growth and functioning. Disruption of the normal gut microbiota is common in malnutrition, and recent research suggests that without fixing this "immature" microbiota, even children given supplementary food may not be able to thrive. Using a machine-learning technique demonstrated by Arjun Raman and colleagues, Gehrig et al. were able to pinpoint the main types of bacteria present in the healthy gut of Bangladeshi children ages one to 60 months. In a series of experiments in mice and pigs with bacteria-free digestive tracts, the researchers were able to determine which sets of foods were associated with certain bacterial communities, and which could nudge an immature gut microbiota toward a mature configuration that could support a child's growth after severe malnutrition. Their findings suggest that protein-rich plant foods such as chickpeas, bananas and peanut flours support this microbial transition. Children who were fed these items as part of their nutritional recovery increased their levels of protein biomarkers related to growth, immune function, neurodevelopment and bone formation.