The term "nutritious" is being increasingly used by product manufacturers but the term is not currently regulated as a nutrition claim. It is unclear how lay consumers and experts define and interpret the term or how they evaluate the "nutritiousness" of various foods. To address this evidence gap, a mixed methods design was applied and both nutrition experts (n = 206) and lay participants (n = 269) provided definitions of the term "nutritious" and evaluated the "nutritiousness" of 20 different snack foods in a cross-sectional survey. Definitions were analysed using Leximancer and snack evaluations were compared both between groups and with nutrient profile scores (UK Ofcom and Australian Health Star Rating). Expert and lay definitions differed considerably, with experts using terms such as nutrient-density, macro- and micronutrients, kilojoules/Calories, while lay consumers used descriptions such as fuel, fresh, natural, body needs, and functioning. Snack evaluations were highly correlated between groups (Rs > 0.89, p < 0.001) and between nutrient profile scores (Rs > 0.75, p < 0.001). However, mean perceptions significantly differed for 18 out of 20 foods with the largest difference for yoghurts (p < 0.05). There are discrepancies between expert and lay perceptions of snack foods and the definition of the term "nutritious". The results highlight the need for an agreed definition and the potential regulation of the term "nutritious" in food marketing.
Keywords: food labels; health claim; health perception; healthy choice; language analysis; mixed-method design; portion size.