Plant-based Versus Animal-based Oral Nutritional Supplements

Background information: Many people who are admitted to the hospital are at risk of malnutrition. In some patient groups, this can be as high as 40%. When someone is not eating enough, the dietitian often recommends oral nutritional supplements (ONS). These are energy- and protein-rich drinks that help patients get enough nutrition. They can reduce complications, lower the chance of being readmitted to the hospital, and help improve body weight and physical functioning. In the Netherlands, the Ministry of Health and the Dutch Federation of University Medical Centers have signed the Green Deal "Working together on sustainable care." One of the goals is to make healthcare greener and climate-neutral by 2026. This also applies to medical and non-medical nutrition, including ONS. Because of this, there is increasing attention on developing ONS that contain more plant-based proteins, which may be more sustainable. What do will the investigators find out? It is unknown how plant-based ONS work when patients use them for a longer period of time. For example: * Do they help patients get enough energy and protein? * What are the effects on physical and clinical outcomes? Before a large study with many patients is started, it is important to first test whether this type of research is feasible. Feasibility in terms of * Recruitment rate * Drop-out rate * Adherence to the ONS advice * Study measurements (succesfull vs unsuccesfull measurements) To answer these questions, a smaller pilot study will be conducted in which plant-based ONS will be compared to animal-based ONS. What does this study look like? Inclusion criteria: Patients from the departments of medical oncology, lung diseases, cardiology, cardiothoracic surgery, and orthopedics at Maastricht UMC+ and Radboudumc. These are patients who are currently not eating enough. These patients receive advice from the dietitian to take at least two bottles of ONS per day. If they want to participate in the study, they will be randomly assigned to one of two products: * Animal-based (milk protein): Fresubin YoDrink Raspberry© * Plant-based (soy protein): Fresubin Plant-Based Drink Vanilla© Measurements will be performed at the start of the study and again after three months. In the meantime, the researcher will contact the patient twice by phone to ask how things are going.