Adolescence is characterised by rapid growth and development that increases energy and nutrient requirements. For adolescent athletes, these requirements are further elevated because of the demands of training and competition. Adequate nutrition is therefore essential to support health and performance. While previous reviews have examined dietary intakes among youth athletes(1-3), none have systematically assessed whether these intakes were evaluated against established nutrition guidelines. This review aimed to identify studies investigating dietary intake in adolescent and young adult athletes and determine the proportion of studies that assessed dietary adequacy relative to recommendations. A systematic search of CINAHL, Emcare, MEDLINE, Scopus, SPORTDiscus and Web of Science identified studies reporting dietary intake in adolescent and young adult athletes (12 – 24 years) across all sports and competition levels. Eligible studies were reviewed to determine whether dietary intake data were compared with established nutrition recommendations (e.g., national dietary guidelines or sports nutrition guidelines). 28,760 records were identified, with 1,573 retained for full text review; 398 studies ultimately met the inclusion criteria. Studies spanned the period from 1978 to 2026, with over half (n = 201, 51%) conducted within the last decade (2017 – 2026). Of these, 37% included only female athletes, 34% only male athletes and 29% mixed-sex cohorts. Forty-six percent investigated individual sports, 33% team sports, 19% individual and team sports combined, and 1% did not specify sport type. The largest number of studies were conducted in the USA (n = 112), followed by Japan (n = 35), Spain (n = 25) and Brazil (n = 19). Eleven studies (3%) were conducted in Australia. Overall, 291 studies (73%) compared dietary intake against recommendations for energy and/or macronutrients. These recommendations were derived from 161 unique nutrition guidance sources published between 1977 and 2025. Most were sport- or athlete-specific recommendations (n = 103, 64%), while the remainder were general population guidelines (n = 58, 36%). Sources included narrative reviews or expert guidance (n = 88, 55%), population dietary reference standards (n = 53, 33%), and consensus statements or position stands (n = 20, 12%). Overall, 66% of studies reported that athletes did not meet energy recommendations, 53% did not meet carbohydrate recommendations. Comparatively, 64% met protein recommendations, and 39% met fat recommendations. Assessment of dietary intake in adolescent and young adult athletes has increased substantially in recent years, reflecting growing recognition of the importance of nutrition for athlete health and performance. However, significant gaps remain, particularly regarding team sport athletes and Australian cohorts. Of particular concern is that inadequate energy intake, largely driven by insufficient carbohydrate intake, is frequently reported in adolescent and young adult athletes. Addressing these evidence gaps will strengthen the current knowledge base and help inform targeted nutrition strategies for young athletes.