To meet nutrient recommendations, most French adults need to expand their habitual food repertoire.

Simultaneous dietary achievement of a comprehensive set of nutrient recommendations is difficult. Our objective was to assess the feasibility of achieving a set of 30 nutrient recommendations at the individual level and characterize factors associated with feasibility. Seven-day food records collected from adults participating in the French national food consumption survey (n = 1171) were modified using an individualized diet optimization approach. For each individual, departure from his/her recorded diet was minimized, using only foods reported in his/her weekly diet record to fulfill a set of nutritional constraints. These constraints aimed to achieve or exceed the French Estimated Average Requirements and varied depending on the individual's gender, age, and observed nutrient intake levels. Acceptability constraints ensured realistic food portion sizes and food patterns. Model feasibility (i.e. percentage of feasible optimized diets) was calculated for all diets and by tertiles of dietary variety (i.e. the number of foods in the weekly food repertoire). Among the 1171 modeled diets, only 22% were mathematically feasible, showing that 78% of French adults would need to expand their weekly food repertoire to fulfill nutrient recommendations. Model feasibility increased from 6.6 to 50.3% and from 2.7 to 42.9% in tertiles 1 and 3 of dietary variety for men and women, respectively. The vitamin D constraint was the most difficult to fulfill (feasibility doubled after its removal), followed by sodium (maximum), magnesium (minimum), and SFA (maximum). The new approach developed in this study provides a method for identifying nutrient levels to carefully evaluate when establishing recommendations.