The study feed is a high energy (1.5kcal/ml), high protein (7.5g protein/100ml) peptide-based feed, available as a 500ml enteral tube feed, and a 200ml Vanilla-flavour oral nutritional supplement. The study will investigate the gastrointestinal tolerance, compliance and acceptability of the high energy, high protein peptide-based feed in 60 adult patients requiring a peptide-based feed, in several NHS sites across England. Patients will be asked to take the study feed for 28 days. Data will be recorded using questionnaires with no invasive measures.