Collaborative care is crucial in in under fuelling to prevent further deterioration and can prevent progression to an eating disorder. Our case: Marnie is a 22-year-old woman with a two-year history of amenorrhoea. She exercises at high intensity every day, is underweight, and describes that she is lacking her usual zest for life. She has undergone a thorough medical assessment, and the diagnosis of low energy availability (LEA) has been made with other secondary causes of amenorrhoea excluded. Marnie has already seen a dietitian, engaged a trainer and understood the need to increase her energy intake, reduce her training load, and incorporate regular rest days. Despite understanding the advice, she is struggling to make these changes. Practical clinical pearls: 1. Engaging in food restriction and high exercise can be a trigger of onset of an ED in vulnerable individuals 2. There can be a gradual transition and progression from under-fuelling and over-exercising for reasons associated with sport goals to an ED which at times can be difficult to differentiate 3. People with REDs display symptoms and traits reminiscent of those seen in people with an ED (cognitive and behavioural rigidity, habit and rule based behaviour, difficulty not engaging in exercise 4. Once an ED has become activated treatment of the ED will need to become priority, i.e., treatment will need to go beyond addressing the physical sequelae of REDs 5. Early intervention is crucial. Expert bio: Dr Megan Ogilvie is the Business Director at ERH Associates Subspeciality expertise in menopause, PCOS, athlete hormone health. PMS/PMDD, VSCs and gender-affirming medicine. Megan completed her endocrinology training in Auckland and then undertook a fellowship in London at St Bartholomew's and University College of London Hospitals. Since returning to New Zealand, Megan has worked in both general and reproductive endocrinology at Fertility Associates and at Auckland District Health Board, and now at ERH Associates. Megan has particular reproductive endocrine interests in menopause, polycystic ovarian syndrome, gender-affirming care, as well as athlete hormone health and energy deficiency. Megan was a founding member of WHISPA (a medical advisory board to High Performance Sport New Zealand, now disestablished) and has run training workshops for High Performance Sport NZ in the area of female athlete hormone health. Megan is the New Zealand representative on the board of the Australasian menopause society. Dr Roger Mysliwiec is an Auckland-based medical specialist with extensive expertise in psychosomatic medicine and eating disorders. Trained in Germany, he has over 35 years of clinical experience across hospital, public sector, and private practice settings. He previously served as Clinical Director of Auckland’s Regional Eating Disorders Service (1999–2014) and has played a key role in developing and strengthening eating disorder services in New Zealand. His clinical work focuses on assessment and treatment of anorexia nervosa, bulimia nervosa, binge eating disorder, and ARFID, particularly in adults and older adolescents. He integrates evidence-based psychological therapies including CBT, MANTRA, SSCM, and adolescent-focused approaches, alongside neuroscience-informed psychotherapy. Dr Mysliwiec also provides specialist consultations, medication reviews where appropriate, and multidisciplinary treatment planning. In addition, he is an experienced supervisor and educator, mentoring clinicians and contributing to professional development in eating disorders and mental health across New Zealand and Australia. Resources: Australian Institute of Sport. Female Performance & Health Initiative: Education modules [Internet]. Canberra (AU): Australian Sports Commission; [cited 2026 Jun 17]. Available from: https://www.ausport.gov.au/ais/fphi/education. (Australian Sports Commission) De Souza, M.J., Williams, N.I., Misra, M. et al. 2025 Update to the Female Athlete Triad Coalition Consensus Statement Part 1: State of the Science and Introduction of a New Adolescent Model. Sports Med 56, 327–373 (2026). Available from: https://doi.org/10.1007/s40279-025-02333-z Everett S. Optimizing Performance Nutrition for Adolescent Athletes: A Review of Dietary Needs, Risks, and Practical Strategies. Nutrients. 2025;17(17):2792. doi: https://doi.org/10.3390/nu17172792. Gallant TL, Ong LF, Wong L, Sparks M, Wilson E, Puglisi JL, Gerriets VA. Low energy availability and relative energy deficiency in sport: a systematic review and meta-analysis. Sports Med. 2025;55(2):325–339. Available from: https://doi.org/10.1007/s40279-024-02130-0 Gould RJ, Ridout AJ, Newton J. Relative energy deficiency in sport (RED-S) in adolescents – a practical review. Int J Sports Med. 2023;44:236–246. Available from: https://doi.org/10.1055/a-1947-3174 Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1098. doi: https://doi.org/10.1136/bjsports-2023-106994 Listen here: