Undernutrition among older adults is a multifaceted challenge where the palatability, availability and cost of food intersect with metabolic effects and health outcomes. The research partners representing six different countries in EAT4AGE will focus on some of the most important age-related changes that should be overcome to prevent undernutrition and avoid impaired muscle function; i.e. decline in digestive functions, oral processing, sensory perception and appetite. EAT4AGE will investigate how food reformulation can be used to combat undernutrition and improve the health of older people. The project will specifically address the choice of protein source and type of processing in developing innovative nutrient-dense foods with improved acceptability, as protein source may affect digestibility in older adults as well as appetite and satiety. Initial screening will result in formulation of innovative energy- and nutrient-dense food prototypes based on cereals, dairy and meat. Palatability, and appetite/satiety of nutritionally enhanced innovative products will be tested in older adults in all countries with culturallyrelevant food prototypes. In-vitro testing of selected prototypes for textural roperties will be performed to develop a textural ingredient toolbox for developing innovative food products for older adults. The digestive processes change with increased age, thus, food prototypes will be tested using a semidynamic in vitro digestion model. This will provide new knowledge for older adults, that will be disseminated with the INFOGEST network as discussion partner and dissemination platform. Selected food prototypes will also be tested for anabolic response in skeletal muscle among older adults. This will provide further knowledge on how the different protein sources in the selected food prototypes are processed in older adults.