Changes in diet quality 6 and 12 months post-intervention: the Healthy Habits, Healthy Girls: a Brazilian study

ABSTRACT Objective To determine the sustainability of food quality in an obesity-prevention strategy for adolescent girls. Methods The study is a randomized controlled trial with 253 girls (Mean=15.61, 95% Confidence Interval 15.51-15.72) enrolled in 10 vocational schools in São Paulo. The diet intake was determined using a “Food Frequency Questionnaire” and analyzed according to the Brazilian Healthy Eating Index-Revised adequacy, moderation, and overall scores. The adolescents’ dietary intake was compared to the baseline 6 months and 12 months post-intervention. Descriptive statistics and analyses of covariance were used, considering a 5% significance level. Results Significant increases were found on the components total fruits (F=6.98, p<0.01), total vegetables (F=5.76, p=0.02), beans (F=5.96, p=0.02), and whole cereals (F=12.35, p<0.001). However, there was also a significant decrease on the scores for milk and dairy (F=6.48, p=0.02), and oils (F=5.98, p=0.02). At 12-month post intervention, improvement on the overall score was found (F=3.89, p=0.05), but there was a decrease on the component whole cereals (F=11.85, p<0.001), as well as in milk and dairies (F=6.38, p=0.02). Despite no significant effect for the SoFAAS component, a moderate effect size was revealed (d=0.56). Conclusion There were significant effects on some diet quality components and for the overall scores at 6-month and 12-month post intervention. Therefore, sustainable dietary changes should be the focus of obesity prevention programs for adolescents. Socio-economic influences on diet behaviors would also need to be acknowledged.

摘要
研究目的：明确针对青春期女性的肥胖预防策略中食品质量的可持续性。
研究方法：本研究为随机对照试验，共纳入253名女性青少年（平均年龄15.61岁，95%置信区间15.51~15.72），招募自圣保罗州的10所职业学校。膳食摄入情况通过“食物频率问卷（Food Frequency Questionnaire）”进行评估，并依据“巴西修订版健康饮食指数（Brazilian Healthy Eating Index-Revised）”的充足性、适度性及总评分进行分析。将青少年的膳食摄入情况与干预前基线、干预后6个月及12个月的数据进行对比。本研究采用描述性统计及协方差分析，显著性水平设定为5%。
研究结果：结果显示，总水果（F=6.98，p<0.01）、总蔬菜（F=5.76，p=0.02）、豆类（F=5.96，p=0.02）及全谷物（F=12.35，p<0.001）相关评分均出现显著提升。但乳类及乳制品（F=6.48，p=0.02）、油脂类（F=5.98，p=0.02）相关评分则出现显著下降。干预后12个月时，总健康饮食评分出现改善（F=3.89，p=0.05），但全谷物（F=11.85，p<0.001）及乳类与乳制品（F=6.38，p=0.02）相关评分出现下降。尽管SoFAAS成分未观察到显著效应，但效应量中等（d=0.56）。
研究结论：干预后6个月及12个月时，部分膳食质量成分及总评分均出现显著变化。因此，可持续的膳食改变应成为青少年肥胖预防项目的核心关注点。同时，社会经济因素对膳食行为的影响也应得到重视。