Transtheoretical model-based nutritional interventions in adolescents: a systematic review.

BACKGROUND: Literature has shown a tendency of inadequate dietary intake among youth, consequently, nutritional interventions are required. The transtheoretical model (TTM) classifies individuals based on their readiness to change. This model is widely used for health education interventions with proven efficacy. PURPOSE: This review aimed to weigh the strength of evidence about the TTM usage in nutritional interventions for adolescents and its effectiveness regarding dietary intake. METHODS: This study followed the PRISMA guidelines. Eligible studies were input into Mendeley software. The Adolec, Google Scholar, LILACS, PsycINFO, PubMed, Science Direct and Web of Science databases were searched. Only full original articles written in English, Spanish or Portuguese on randomized controlled trials and quasi-experimental designs that applied the TTM in the design of nutritional interventions targeting adolescents were included, with no restrictions on publication date. The quality and risk of bias was evaluated with the Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. RESULTS: The initial search yielded 3779 results. Three studies were rated as strong, six as moderate and five as weak. The final sample of 14 articles included adolescents that were mostly recruited from schools, with interventions ranging from one month to three years. The TTM was used alone or combined with other behavior-change theories and most of the interventions involved digital technology. The nutritional topics covered included fruit and vegetable consumption, low-fat diet, and cooking skills. Four studies presented improvement in fruit and vegetable consumption and four progressed through stages of change. Participants from two interventions reduced fat intake. At the end of one intervention, all the participants were in action and maintenance stages. CONCLUSION: The TTM seems to be a successful strategy for nutritional intervention aiming at improving dietary intake in adolescents. Its application in different contexts shows that the TTM is flexible and possible to be implemented in many settings. The use of the model is shown to be restricted to the stage of change' construct. Further studies should use all constructs of the TTM in the design and compare the TTM with other behavior-change theories to better understand its effectiveness.

Family meal frequency and its association with food consumption and nutritional status in adolescents: A systematic review.

This systematic review evaluated the association between frequency of family meals (FFM) and nutritional status (NS) and/or food consumption (FC) in adolescents. The protocol was registered with PROSPERO (CRD42017062180) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. No publication date, language, or meal type restrictions were imposed. Only full-text original articles were included; qualitative studies were excluded. Studies were identified by searching 5 electronic databases (PubMed, Web of Science, Scopus, BVS Brazil, and Adolec) and gray literature (Google Scholar) and by scanning reference lists of included articles. Risk of bias was assessed using the Newcastle-Ottawa scale for cohort and cross-sectional studies. Initial search yielded 2001 results and 47 articles were included. An updated literature search added 3 articles. Of the 50 studies included, 25 studied the association between FFM and NS, 32 investigated the association between FFM and FC, being that seven studies analyzed both outcomes. Thirty-four were cross-sectional studies, 12 were longitudinal studies, and 4 studies analyzed both cross-sectional and longitudinal data. Thirty-five studies were rated as having good quality, whereas 19 were of fair quality. Sample size ranged from 140 to 102 072 participants. Most investigations evaluated the frequency of breakfast, lunch, and/or dinner/supper/evening meals over a 1-week period. Seventeen studies identified a positive relationship between high FFM and better NS, and 26 found a positive association between high FFM and better FC. In conclusion, this review showed an association between FFM and healthy dietary patterns, such as increased consumption of fruits and vegetables. Further research is needed to understand the association between FFM and NS, since some studies showed a protective role of family meals against obesity in this age group, whereas other studies identified no significant association between these variables.