**Background:** The 2014 Brazilian Dietary Guidelines emphasize not only what adolescents eat but also how they eat—encompassing meal regularity, eating environments, attention during meals, and social company. Despite evidence linking poor eating contexts to lower diet quality and higher BMI in adolescents, no prior studies had produced detailed epidemiologic diagnoses of eating contexts according to these guidelines in Brazilian youth. This study aimed to describe eating contexts and their associations with socio-demographic factors in a sample of Brazilian adolescents.
**Methods:** Data were drawn from the EVA-JF Study, a school-based cross-sectional health survey conducted from May 2018 to May 2019 in 29 public schools in Juiz de Fora, MG, Southeast Brazil. The sample included 835 adolescents aged 14–19 years, selected via stratified proportional allocation by administrative region, school, school year, class, and sex. Inclusion criteria required enrollment in morning shifts of the last year of elementary school or any of three high school years, without chronic medication use, pacemakers, orthopedic prostheses, or disabilities. Pregnant or lactating girls were excluded. Eating contexts were assessed via a 23-item exploratory questionnaire based on the Brazilian Dietary Guidelines, covering breakfast, lunch, dinner, and snacks. Questions addressed meal regularity, location (home vs. out), environment (quiet vs. noisy), posture (sitting at table vs. couch/bed vs. standing/walking), screen use, and company. The questionnaire demonstrated high internal consistency (Cronbach's α=0.856). Cluster analysis (agglomerative hierarchical method) identified three clusters explaining 51.7% cumulative variance: cluster 1 'appropriate eating contexts at breakfast, lunch and dinner' (n=595), cluster 2 'inappropriate eating context at breakfast' (n=144), and cluster 3 'inappropriate eating context at dinner' (n=96). Multinomial logistic regression models (unadjusted and adjusted) were used to estimate associations between socio-demographic factors and cluster membership, with cluster 1 as reference.
**Key Results:** The sample was 57.5% female, mean age 16.1 years (SD=1.2), 64.5% non-white, 75.0% residing in owned homes, and 58.5% middle socioeconomic status. For breakfast, 52.9% of adolescents did not eat it regularly (19.8% none; 33.1% 1–4 days/week), 46.6% ate sitting/lying on couch/bed or standing/walking, 36.3% often/always ate in front of screens, and 70.8% usually ate unaccompanied. For lunch, 88.9% ate regularly (5–7 days/week), but 49.7% ate in non-table postures, 60.6% often/always used screens, and 47.5% ate unaccompanied. For dinner, 39.3% did not eat regularly (11.5% none; 27.8% 1–4 days/week), 18.4% switched regular dinner for fast food/snacks 5–7 days/week, 58.5% ate in non-table postures, 63.7% often/always used screens, and 36.1% ate unaccompanied. For snacks, 57.1% often/always snacked near main meals, 45.9% in front of screens, and 18.7% while studying. In adjusted multinomial logistic regression, female sex was significantly more likely to belong to cluster 2 (OR=1.60, 95% CI 1.06–2.40) and cluster 3 (OR=2.15, 95% CI 1.31–3.54). Adolescents aged 14–15 years were less likely to belong to cluster 2 (OR=0.46, 95% CI 0.25–0.86). Higher maternal education was associated with greater likelihood of cluster 3 membership: complete higher education (reference), complete high school (OR=0.43, 95% CI 0.24–0.79), complete elementary/incomplete high school (OR=0.29, 95% CI 0.15–0.54), illiterate/incomplete elementary (OR=0.20, 95% CI 0.04–0.95).
**Clinical Implications:** This study reveals that a majority of Brazilian adolescents engage in eating contexts that deviate from national dietary guideline recommendations, with particularly high rates of meal skipping, eating in front of screens, and eating alone. The associations with female sex and higher maternal education suggest that interventions must be tailored to specific demographic groups. The paradoxical finding that higher maternal education was linked to worse dinner contexts may reflect nutritional transition dynamics in developing countries, where higher socioeconomic status groups adopt less traditional eating patterns. These findings support the need for school-based public health policies that address not just nutritional content but the broader context of eating—including meal regularity, environment, and social engagement—as a strategy to improve adolescent health outcomes.