RESUMEN
BACKGROUND: The trolley meal system allows hospital patients to select food items and portion sizes directly from the food trolley. The nutritional status of the patient may be compromised if portions selected do not meet recommended intakes for energy, protein and micronutrients. The aim of this study was to investigate: (1) the portion size served, consumed and plate waste generated, (2) the extent to which the size of meal portions served contributes to daily recommended intakes for energy and protein, (3) the predictive effect of the served portion sizes on plate waste in patients screened for nutritional risk by NRS-2002, and (4) to establish the applicability of the dietary intake monitoring system (DIMS) as a technique to monitor plate waste. METHODS: A prospective observational cohort study was conducted in two hospital wards over five weekdays. The DIMS was used to collect paired before- and after-meal consumption photos and measure the weight of plate content. RESULTS: The proportion of energy and protein consumed by both groups at each meal session could contribute up to 15% of the total daily recommended intake. Linear mixed model identified a positive relationship between meal portion size and plate waste (P = 0.002) and increased food waste in patients at nutritional risk during supper (P = 0.001). CONCLUSION: Meal portion size was associated with the level of plate waste produced. Being at nutritional risk further increased the extent of waste, regardless of the portion size served at supper. The use of DIMS as an innovative technique might be a promising way to monitor plate waste for optimizing meal portion size servings and minimizing food waste.