Aims and background: The nutrition transition represents a significant shift in food choices and lifestyle habits, influenced by social, political, and economic factors. Rapid global fast-food chain expansion and the influence of Western culture have led to a decline in traditional home-cooked meals. Adolescents in affluent countries struggle to meet nutritional standards, often consuming calorie-dense, nutrient-poor foods. This trend is observed in emerging nations as well, posing long-term health risks such as diabetes, obesity, and various cancers. It is important to address teenagers’ eating habits to mitigate these health risks, with females generally having healthier diets than males across different ethnic groups and regions. The aim of this study is to systematically review and analyze the dietary patterns of adolescents across various regions, identify the factors that contribute to unhealthy eating habits, and assess the impact of socioeconomic, cultural, and regional factors on adolescent nutrition. The study seeks to provide evidence-based recommendations for targeted nutritional interventions and educational strategies to improve eating habits, prevent chronic diseases, and promote long-term health in adolescents. Materials and methods: In a thorough 15-day search, 47 studies were identified by thoroughly searching PubMed, Medline, World Health Organization (WHO), Google Scholar, and government websites. After excluding 17 studies due to the unavailability of the full text, 30 articles were chosen and assessed for relevance to the review objectives. Results: The studies highlighted diverse dietary patterns among adolescents across various regions. In urban India, adolescents exhibited poor diet quality, characterized by low consumption of vegetables and fruits, alongside high intake of high-calorie snacks and caffeinated drinks, particularly among boys. In South Kerala, food frequency questionnaires (FFQs) tended to overestimate dietary intake compared to food records. In Spain, adolescents shifted toward greater consumption of meat and animal products, with a concurrent decrease in energy intake. Brazilian adolescents displayed distinct dietary patterns, with socioeconomic factors playing a significant role, and older adolescents were more likely to adopt healthier eating habits. United States adolescents in Chicago scored lower on diet quality compared to national averages. Across multiple studies, the availability of healthy foods at home, parental dietary habits, and socioeconomic status were strongly linked to better eating behaviors, while the presence of energy-dense snacks and sugary beverages was associated with poorer diet quality. Conclusion: The existing research emphasizes the urgent need for targeted nutritional interventions and educational efforts to improve the dietary behaviors of adolescents. These studies consistently highlight the importance of promoting healthy eating habits, enhancing access to nutritious foods at home, and tailoring interventions to diverse cultural, socioeconomic, and regional contexts. The shift from traditional, healthier diets to increased consumption of high-fat, low-nutrient foods among adolescents underscores the need for immediate action. Effective strategies should reinforce family meal routines, enhance school nutrition programs, and encourage dietary diversity to mitigate the risks of obesity and chronic diseases in this age-group. Clinical significance: The poor dietary habits observed in adolescents are directly linked to an increased risk of obesity, type 2 diabetes, and other chronic diseases. Early intervention and targeted nutritional counseling by healthcare providers are crucial to prevent these conditions, emphasizing the need for routine dietary assessments in adolescent care to promote long-term health.