Consumers' knowledge of healthy diets and its correlation with dietary behaviour

Procedural nutrition knowledge is knowledge of how to eat a healthy diet. This type of knowledge potentially plays an important role in dietary behaviour. Previous studies of consumers' nutrition knowledge did not systematically assess procedural nutrition knowledge. Thus, we administered a survey of procedural nutrition knowledge to Swiss consumers to assess the prevalence of misconceptions about healthy eating.

We developed 13 procedural nutrition knowledge items. Nine items were based on qualitative consumer interviews and four items were derived from expert guidelines. The items had a true/false format. We administered the items to a random population sample in a written postal survey (n = 1,043). The survey also assessed the consumers' self-reported food consumption. For each respondent, we computed the number of correctly answered knowledge items and we correlated this number with food consumption frequencies.

The procedural nutrition knowledge items received between 3% and 38% incorrect answers. Individuals with a higher number of correctly answered items consumed more vegetables (r = 0.29). Higher knowledge was associated with the female gender, younger age, higher education, nutrition-related qualifications and not being on a diet (P < 0.001).

Our findings indicate that misconceptions exist in the general population about healthy eating. These misconceptions are associated with a decreased consumption of foods usually defined as healthy. Some population sub-groups seem particularly susceptible to holding such misconceptions. The implications for nutrition education, particularly concerning the role of fruit and vegetable consumption as well as the food pyramid are discussed.