Higher Diet Quality in Adolescence and Dietary Improvements Are Related to Less Weight Gain During the Transition From Adolescence to Adulthood.

OBJECTIVES
To examine the previously validated A Priori Diet Quality Score (APDQS), and weight change among adolescents transitioning into young adulthood.

STUDY DESIGN
Young people were recruited in middle/high schools and followed for 10 years. Participants reported diet and weight in 1999 (mean age, 15 years), 2004 (20 years), and 2009 (25 years). The analytic sample (n = 2656) had dietary intake assessments in 1999 and at least one other assessment. The APDQS (without alcoholic items) was based on 13 beneficial food groups, 12 adverse food groups, and 9 neutral food groups to capture aspects of Mediterranean/prudent diets, focusing on foods that are varied, based on nutritionally rich plants, and less processed.

RESULTS
From mean age 15 to 25 years, mean (SD) weight increased from 61.0 (14.7) kg to 76.1 (18.8) kg, and APDQS increased from 43.1 (11.1) points to 45.6 (10.7) points. Within-person tracking correlation of the APDQS was 0.35 at mean age 15-20 years, increasing to 0.49 at 20-25 years. Independent of lifestyle factors and energy intake, a 15-point (IQR) higher APDQS in 1999 was associated with 1.5 kg (95% CI, 0.7-2.3 kg) less weight gain over 10 years, The increase in APDQS over time was similarly associated with less concurrent weight gain. Findings were stronger for models of excess weight gain.

CONCLUSION
Higher diet quality, based on an assessment of dietary patterns in and after adolescence, was associated with reduced weight gain during the next 10 years. Establishment of high-quality dietary patterns in adolescence may help mitigate excess weight gain by young adulthood.