Assessing dietary exposure or nutrient intakes requires detailed dietary data. These data are collected in France by the cross-sectional Individual and National Studies on Food Consumption (INCA). In 2014–2015, the third survey (INCA3) was launched in the framework of the European harmonization process which introduced major methodological changes. The present paper describes the design of the INCA3 survey, its participation rate and the quality of its dietary data, and discusses the lessons learned from the methodological adaptations.

Two representative samples of adults (18–79 years old) and children (0–17 years old) living in mainland France were selected following a three-stage stratified random sampling method using the national census database.

Food consumption was collected through three non-consecutive 24 h recalls (15–79 years old) or records (0–14 years old), supplemented by an FFQ. Information on food supplement use, eating habits, physical activity and sedentary behaviours, health status and sociodemographic characteristics were gathered by questionnaires. Height and body weight were measured.

In total, 4114 individuals (2121 adults, 1993 children) completed the whole protocol.

Participation rate was 41·5% for adults and 49·8% for children. Mean energy intake was estimated as 8795 kJ/d (2102 kcal/d) in adults and 7222 kJ/d (1726 kcal/d) in children and the rate of energy intake under-reporters was 17·8 and 13·9%, respectively.

Following the European guidelines, the INCA3 survey collected detailed dietary data useful for food-related and nutritional risk assessments at national and European level. The impact of the methodological changes on the participation rate should be further studied.