Protein-calorie malnutrition is a frequent comorbidity in hospitalized patients and there is evidence that the nutritional status may influence the response to drug treatment, mortality, susceptibility to infections, the patient's functional status, duration of hospital stay and, consequently, overall healthcare costs. The causes of malnutrition are manifold. The underlying disease may in fact lead to an increase in the patient's energy needs, whether or not associated with a reduction in caloric intake. The same therapeutic treatments can further worsen the energy balance without considering that the patient can be kept fasting for the execution of some diagnostic procedures. Therefore, a further deterioration of nutritional status during hospitalization could occur.

International guidelines underline the utility to set a nutritional support whenever this is necessary, not only to prevent or treat malnutrition but also improve clinical outcomes. In this perspective, the improvement of oral diet and the use of oral nutritional supplements (ONS) represent the first-line strategy of intervention. Previous studies have shown that nutritional counseling, with or without the use of ONS, in patients with chronic disease is able to improve the calorie-protein intake, prevent deterioration of nutritional status, as well as to increase to a certain extent body weight. Particularly, energy-dense are more effective in increase energy intake. These data have highlighted the importance of a proper evaluation of the nutritional status of early detection of patients who could benefit of nutritional support. However, the independent role of the ONS in improving clinical outcome still needs to be established.

Inclusion Criteria:

• Nutritional Risk Score [NRS-2002] ≥3
• assessed within 48 hours since admission
• expected length of stay ≥7 days
• written informed consent

Exclusion Criteria:

• age < 18 years
• ongoing or indication to artificial nutrition
• severe hypophagia (intake <50% of estimated requirements)
• scheduled for surgery
• indication to fasting
• physician-based contra-indication to use of liquid oral nutritional supplements (vomitus, severe nausea, diarrhea, dysphagia)
• physician-based indication to the of disease-specific oral nutritional supplements (e.g. kidney failure or pressure ulcers)
• terminal illness
• unavailability to planned measurements