Impact simulation of portion guidance on commonly consumed packaged food to reduce discretionary energy and public health sensitive nutrients in the United States, United Kingdom, and France

Excessive consumption of discretionary food is a global concern linked to obesity prevalence. Providing reference portion sizes and reducing portion size is a potential solution to tackle this issue. The aim of this study was to model the impact of systematically established portion values, without changing food choices, on discretionary energy and public health-sensitive nutrients using nationally representative datasets from the United States (NHANES), United Kingdom (NDNS), and France (INCA3). Diet modeling was used to adjust large portions to reference portion sizes per eating occasion for selected discretionary, energy-dense food categories. Nutritional quality and adherence to World Health Organization guidelines were compared before and after substitutions. Linear regressions assessed whether reductions in daily total energy and added/free sugar were associated with participants’ demographic and anthropometric characteristics. After substitution, daily energy from discretionary foods decreased by 5.4 percentage points for NHANES (mean ± SD from 20.7 ± 13.1 to 15.3 ± 9.8%, p < 0.001), 3.1 percentage points for NDNS (from 15.6 ± 9.8 to 12.5 ± 8.0%, p < 0.001), and 3.6 percentage points for INCA3 (from 16.1 ± 10.7 to 12.5 ± 8.1%, p < 0.001) data. Following portion guidance improved diet quality, reduced public health-sensitive nutrients (e.g., saturated fat, added sugar, sodium) and enhanced adherence to WHO guidelines. Older age was associated with smaller reductions in discretionary energy and added/free sugar among participants in UK and France. Adjusting portion sizes without altering food preferences may decrease energy and public health-sensitive nutrients intakes. Further research is needed to explore these findings in other regions and their potential health outcomes.