Nutrition, Sedentary Behaviour and Physical Activity in Undergraduate Students: A Scoping Review with PRISMA-ScR Checklist

Background/Objectives: University students are particularly vulnerable to unhealthy lifestyle behaviours, including poor dietary habits, insufficient physical activity, and prolonged sedentary time. While these three behaviours have each been extensively studied individually, the extent to which they have been jointly investigated as distinct constructs in the same undergraduate populations remains unclear. This scoping review aimed to map the available evidence jointly addressing dietary habits, sedentary behaviour, and physical activity among undergraduate university students. Methods: Following the PRISMA-ScR guidelines, a systematic search was conducted on PubMed and Scopus (search date: 27 June 2026), covering records published between 2014 and 2026 in English. Studies were eligible if they measured all three constructs (diet, sedentary behaviour, and physical activity) as distinct outcomes in undergraduate populations aged 18 years or older. Results: Of 1910 records identified, 70 studies met the eligibility criteria, comprising 62 primary studies and 8 ongoing study protocols. The primary studies spanned 26 countries across five continents, and most used cross-sectional designs; only one intervention study was identified. Across studies, inadequate diet, low physical activity, and elevated sedentary time were common and frequently co-occurred within individuals, with associations reported for mental health, body image, and weight-related outcomes. Sedentary behaviour was the construct most often absent from otherwise relevant studies and was consistently elevated when measured. Conclusions: Across the 62 primary studies spanning 26 countries, a broadly consistent pattern of suboptimal diet, insufficient physical activity, and elevated sedentary time was observed among undergraduate students.