Healthy but hazy? Consumers' understanding of the healthiness and nutritional value of food groups.

Food-based dietary guidelines aim at promoting healthy dietary choices. Poor adherence has been partially explained by a lack of nutrition knowledge. Yet, little attention has been paid to the specific understanding of the referenced food groups, which is however essential to translate guidelines into practice. In this study, we therefore investigated people's understanding of food groups via their food choices as a rection to dietary prompts (typical, healthy, low-calorie, low-sugar meals). Ninety-six participants (66.7 % female, mean age 22.8 years) self-served four meals at a buffet with realistic food replicas ("Fake Food buffet"). Results indicated that certain food groups were associated with specific dietary characteristics (e.g., vegetables as low in calories, nuts and pulses as healthy and low in sugar). Although other food groups (i.e., fried foods, desserts and other sugary foods) were not associated with any of these characteristics, they were still chosen in typical meals, indicating a knowledge-behaviour gap. Results emphasize that understanding food groups appropriately is critical but does not ensure translating dietary guidelines into practice accordingly. The reaction to the dietary prompt of a healthy meal came particularly close to dietary guidelines and should thus be promoted in practice.