Assessing served portions plate waste and student acceptability in the Indonesian Free Nutritious Meal Program at a vocational high school

Background The success of school meal programs is determined not only by the food distributed, but also by portion accuracy, nutritional quality, student acceptance, and the amount actually consumed. Objectives This study aimed to (1) describe the portions actually served and their conformity with the guidelines of Indonesia’s Free Nutritious Meal Program (Makan Bergizi Gratis, MBG); (2) quantify observed consumption and component-specific plate waste; (3) assess student acceptability and eating behavior; and (4) integrate data from the same individuals to set menu improvement priorities. Methods A repeated cross-sectional observational evaluation was conducted over one complete 20-day menu cycle at a public vocational high school in West Java, Indonesia. Pre-meal portion weights and before–after photographs scored with modified Visual Comstock categories were obtained daily, and acceptability was assessed using a five-point Likert questionnaire administered after the menu cycle to the students whose trays were observed. The portion and photographic dataset comprised 240 student/tray observations (12 per day). Menu nutrient content was calculated with NutriSurvey, and actual portions were compared with MBG portion standards. Results Overall acceptability was 3.47 ± 0.58 on a 1–5 scale; fruit scored highest (3.88 ± 0.90) and vegetables lowest (3.20 ± 0.97). Mean consumed proportions were highest for animal-source dishes (90.6%) and staple foods (85.6%), and lowest for vegetables (34.0%) and plant-based dishes (45.7%). Staple portions averaged 71.0% of the MBG standard. Served meals provided 477 ± 94.0 kcal, or 66.9% of the 713 kcal lunch target, with protein closest to target (19.9 ± 6.9 g; 94.8%) and fat furthest from it (10.3 ± 3.5 g; 44.8%). In total, 88.8% of students reported not finishing or not consuming MBG meals, and 72.5% added external condiments. Conclusions Vegetables and plant-based side dishes are reformulation priorities due to lower acceptability, high portion variability, and plate waste above 50%. Staple foods require portion standardization, whereas animal-source dishes can serve as a serving-practice benchmark.