By collecting data directly from 20,000 patients and care-givers in hospitals in 31 countries the initiative, now in its second year, is a bid to improve awareness and knowledge of the importance of nutrition in illness recovery - and ultimately reduce health care costs.
While certain illnesses and conditions require specific nutritional interventions to aid recovery, the initiative could also highlight opportunities for companies in the medical nutrition sector to tackle more broad nutrition gaps.
Professor Michael Hiesmayr of the Medical University of Vienna, coordinator of the project, said that preliminary information from last year's NutritionDay indicates that as many as 47 per cent of patients questioned had been hospitalised with signs of disease-related malnutrition.
Once they arrive in hospital, there may be barriers to remedying their nutritional status - such as the illness itself, or the very stress of being in hospital. One in three patients reported eating all that they were served, while one in five said they ate less than a quarter of what they were served or nothing at all.
Only 11 per cent of those who ate little reported that they did not like the food they were given; rather, they cited nausea or lack of appetite as the reason. Not eating properly when recovering from illness can result in hospital stays being extended by as long as six days.
The NutritionDay project was conceived to run for at least three years. By collecting data on one single day each year it audits actual nutrition care and nutrition monitoring, and should facilitate the tracing of changes in local practice and international trends.
The problem of malnutrition in certain sectors of Western populations - especially the elderly - is also being flagged by the European Nutrition for Health Alliance (ENHA), which is lobbying for public health action at EU level.
The multi-disciplinary alliance comprising stakeholders from health care professions, patient groups, non-governmental organisations, governments and industry says that more than 50m Europeans are at risk of malnutrition.
The scope of ENHA's campaign covers the general population, but the largest target group is the over-60s; one third of older people are thought to suffer from malnutrition, which is described as "an imbalance of energy, protein, and other nutrients that causes measurable adverse effects on tissue and body form and function, as well as on clinical outcomes".