Adolescent dietary patterns tend to be of poor quality, dominated by energy-dense, nutrient-poor discretionary food and drinks. It is unclear whether dietary patterns established in adolescence persist, or track into adulthood. This has important implications for targeted interventions and public health policies aimed at preventing obesity and chronic disease. We examined trajectories across adolescence and young adulthood for two major dietary patterns linked to obesity and chronic disease risk factors.
Using data from the Western Australian Pregnancy Cohort (Raine) Study, we analysed intakes of 38 major food groups estimated at 14, 17, 20 and 23 years of age in 1,402 participants (47% male) using evaluated food frequency questionnaires. Two major dietary patterns (‘Healthy’ and ‘Western’) were identified using factor analysis, that were consistent across follow ups. Sex-specific group-based modelling was used to assess variation in individual z-scores for each pattern, to identify major trajectories in scores between 14 and 23 years of age. Individuals were classified into one of two major trajectory groups for each pattern.
The majority of the cohort (71% males, 78% females) formed trajectory groups with consistently low scores for the ‘Healthy’ dietary pattern. The remainder showed either declines in modest scores (females 22%) or consistently modest scores (29% males) for the ‘Healthy’ pattern. For the ‘Western’ dietary pattern, the majority formed trajectories with consistently average ‘Western’ pattern scores (78% males) or low scores that declined over time (84% females). However, a substantial proportion of males (22%) showed a trajectory of steady, marked increases in ‘Western’ pattern scores over time.
Poor dietary patterns established in adolescence are likely to track into young adulthood. Adolescent boys may be particularly prone to poor dietary habits worsening as they enter adulthood. This highlights adolescence and young adulthood as critical periods for interventions to support healthy eating.