**Background:** A healthy diet is critical for growth, development, and chronic disease prevention, yet most Swedish adolescents do not meet dietary recommendations. Whole grain intake is particularly low—only 6% of Swedish adolescents had adequate intake in a 2016–2017 national survey. Whole grain consumption is associated with reduced risk of all-cause mortality, heart disease, type 2 diabetes, colorectal cancer, and obesity. To design effective interventions, comprehensive knowledge of factors influencing adolescents' dietary behaviors is needed.
**Methods:** This study was part of the 2019 'Help a Scientist' project ('The Whole Grain Hunt') coordinated by the Nobel Prize Museum. A total of 1,178 Swedish adolescents from 21 schools across Sweden completed a paper questionnaire examining attitudes, preferences, and perceived behaviors regarding healthy eating and whole grains. Schools were recruited via teacher trade journals and represented a broad geographical and socioeconomic spread. Participants were aged primarily 13–15 years (584 girls, 578 boys, 13 non-binary, 3 unknown). Responses were converted to a 5-point scale. Two groups were created based on self-reported health interest: lower interest in health (LIH, n=458; 39.1%) and higher interest in health (HIH, n=712; 60.9%). Student's t-tests evaluated significant differences (P<0.05) between genders and between HIH/LIH groups. Data quality was assured via 10% random sampling of paper-to-digital transfers; schools with >5% error rate were excluded.
**Key Results:** Overall, 59% of girls and 56% of boys reported trying to eat healthy, but only 42% of girls and 48% of boys felt they succeeded. Taste was the most important factor for eating healthier (girls 68%; boys 72%). For girls, inspiration was also highly valued (70%). The most reported barrier to healthy eating was unavailability of tasty healthy products. Knowledge about health was rated the least important factor—only 32% of LIH adolescents considered it helpful vs. 51% of HIH. Social media was the primary information source (girls 74%; boys 65%; LIH 62%; HIH 72%), followed by parents and teachers.
Regarding whole grains, 87% of girls and 79% of boys considered whole grains quite or very healthy. However, consumption was low: only ≤37% of adolescents 'usually' or 'always' chose whole grain bread or breakfast cereals. Willingness to eat more whole grains was high. The most influential factors were better taste (girls 64%; boys 60%; HIH 62%; LIH 61%) and greater availability at home (girls 60%; boys 54%; HIH 64%) and school (girls 54%; boys 46%). Few adolescents wanted whole grain products to taste like whole grain (girls 9%; boys 13%; HIH 13%; LIH 8%). The HIH group chose whole grain products significantly more often than LIH for all products except rice. Girls were significantly more willing than boys to eat additional whole grain products overall.
**Clinical Implications:** The findings demonstrate substantial potential for improving dietary habits among adolescents, given the high willingness to eat healthier and consume more whole grains despite current low intake. Interventions should prioritize improving the taste and availability of healthy whole grain products in homes, schools, and stores rather than focusing primarily on nutrition education. The Danish Whole Grain Partnership model—which increased whole grain products on the Danish market by 577% (from 190 to 1,097 products in ~10 years) through labeling, campaigns, product development, and public-private partnerships—offers a successful template. Strategies may need tailoring by health interest level and gender, as attitudes and behaviors differed more between HIH and LIH groups than between boys and girls. Limitations include the non-digital survey format (leading to 30% data loss from quality checks), potential bias from students knowing they were in a 'whole grain' project, and reliance on self-reported perceptions rather than actual dietary intake.