Objectives To document the external validation of the Well-Being related to Food Questionnaire (Well-BFQ) by studying variations of scores according to subjects’ nutritional status. The Well-BFQ was developed after conducting interviews with healthy subjects and subjects with digestive, joint or immunity complaints. Its structure was determined using principal component analyses and confirmed using factor analyses with multi-trait analyses. Methods The Well-BFQ has a modular backbone with sub-dimensions measuring pleasure, security, relaxation, digestion and satiety, energy and psychology, health (ageing, bowel movement, immunity and mobility) and food behaviour. Each sub-dimension is rated from 0 to 100; distributions were compared according to the nutritional status of the subjects using variance analyses. Nutritional status was evaluated according to the PNNS questionnaire (French National Health Nutritional Program). Results Subjects (N=444) were aged 42±15 years and 71.6% women; 18.1% had a balanced diet (BD), 14.7% a non-balanced diet (NBD) and 67.1% a standard diet (SD). The majority of the dimensions assessed with the Well-BFQ were significantly higher (i.e. better food-related well-being) in subjects with a BD than in those with a NBD; even the dimensions assessing commensality (eating as a group) and behavioural attitudes toward buying and cooking food. In particular, the security dimension was rated 67.9±19.5 in BD compared with 56.9±25.2 in NBD and 61.1±21.3 in SD (p<0.01) and health benefit was rated 67.4±12.4 in BD compared with 55.9 ±13.9 in NBD and 64.6±12.8 in SD (p<0.0001). Conclusions This study contributes to the external validity of Well-BFQ by demonstrating the expected positive correlation of the well-being it measures and the quality of the diet of the subjects. Its ability to measure well-being differences according eating habits makes it a promising tool for epidemiological surveys and experimental trials.Read less <