A Three-Year Assessment of Food Waste in Rio de Janeiro Municipality (Brazil): A First Step Toward Understanding the Issue in Brazil

Household food waste remains a huge challenge for solid waste management in municipalities worldwide, especially in the Global South. Existing studies that measure food waste (FW) in cities are scarce, have limited geographic scope, and have limited timeframes. In that direction, the current investigation provides data on the FW composition of nine regions of the municipality of Rio de Janeiro (Brazil), based on a three-year sampling across 155 neighborhoods. Waste samples were collected from 2021 to 2023. In total, about 24,038 kg (fresh weight) was analyzed. Results showed that FW accounts for an average of 47.7 ± 1.9% of household waste in the study period. The FW composition in the city of Rio de Janeiro ranged from 60.3–76.5% for fruits, vegetables, and salads, 15.0–25.1% for fine aggregate (small-sized food residues < 2.54 cm, like rice, beans, grains, and fragmented food particles), and 3.2–5.8% for proteins (discarded animal-based protein foods like chicken and meat). The chi-square goodness-of-fit test was applied to evaluate whether the FW composition in each of the nine regions differed from the mean FW composition of the Rio de Janeiro municipality. The findings revealed statistically significant differences ( p -value < 0.05) in the average FW fractions in specific regions and years compared with the city’s average composition. Thus, one of the key takeaways of this investigation was that the percentages of discharged food waste fractions vary over time and across locations, even within the same municipality. The present research took a first step toward understanding the food waste problem in Rio de Janeiro (Brazil) and underscores the importance of monitoring food waste data to guide the development of locally specific strategies for sustainable urban food systems, including waste prevention, recycling, and food recovery.