This is a quasi-experimental study on acute medical wards for older inpatient in two UK hospitals, with a before and after comparison. The intervention involves the provision of additional between-meal fortified foods (enhanced with protein, energy, and micronutrients) and meal supplementation. Daily energy and protein intake will be assessed for three consecutive days during the baseline period and then in the intervention period. Likeability of fortified food and food choices (the number, type, and frequency of fortified foods consumed) will be examined. Likeability of fortified food by patients will be assessed using likeability scales. Interviews or focus groups will be conducted with staff to assess the acceptability of fortified food. Costs related to developing, packing and delivering the fortified foods will be calculated.