Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addiction and food intolerances are lacking. Therefore, the aim of this cross-sectional study was to investigate the association between DE, exercise addiction and food intolerances in athletes at risk of LEA compared to those with low risk. Female endurance athletes, 18–35 years, training ≥5 times/week were recruited in Norway, Sweden, Ireland, and Germany. Participants completed an online-survey comprising the LEA in Females Questionnaire (LEAF-Q), Exercise Addiction Inventory (EAI), Eating Disorder Examination Questionnaire (EDE-Q), and questions regarding food intolerances. Of the 202 participants who met the inclusion criteria and completed the online survey, 65% were at risk of LEA, 23% were at risk of exercise addiction, and 21% had DE. Athletes at risk of LEA had higher EDE-Q and EAI scores compared to athletes with low risk. EAI score remained higher in athletes with risk of LEA after excluding athletes with DE. Athletes at risk of LEA did not report more food intolerances (17 vs. 10%, P = 0.198), but were more frequently reported by athletes with DE (28 vs. 11%, P = 0.004). In conclusion, these athletes had a high risk of LEA, exercise addiction, and DE. Exercise addiction should be considered as an additional risk factor in the prevention, early detection, and targeted treatment of RED-S among female endurance athletes.

Female endurance athletes are considered a high-risk group for developing Relative Energy Deficiency in Sport (REDs). Due to the lack of educational and behavioral intervention studies, targeting and evaluating the effects of the practical daily management of REDs, we developed the Food and nUtrition for Endurance athletes—a Learning (FUEL) program, consisting of 16 weekly online lectures and individual athlete-centered nutrition counseling every other week. We recruited female endurance athletes from Norway (n = 60), Sweden (n = 84), Ireland (n = 17), and Germany (n = 47). Fifty athletes with symptoms of REDs and with low risk of eating disorders, with no use of hormonal contraceptives and no chronic diseases, were allocated to either the FUEL intervention (n = 32) (FUEL) or a 16-week control period (n = 18) (CON). All but one completed FUEL, while 15 completed CON. We found strong evidence for improvements in sports nutrition knowledge, assessed via interviews, and moderate to strong evidence in the ratings concerning self-perceived sports nutrition knowledge in FUEL versus CON. Analyses of the seven-day prospective weighed food record and questions related to sports nutrition habits, suggested weak evidence for improvements in FUEL versus CON. The FUEL intervention improved sports nutrition knowledge and suggested weak evidence for improved sports nutrition behavior in female endurance athletes with symptoms of REDs.

Female endurance athletes are at high risk for developing Relative Energy Deficiency in Sport (REDs), resulting in symptoms such as menstrual dysfunction and gastrointestinal (GI) problems. The primary aim of this study was to investigate effects of the FUEL (Food and nUtrition for Endurance athletes—a Learning program) intervention consisting of weekly online lectures combined with individual athlete-centered nutrition counseling every other week for sixteen weeks on REDs related symptoms in female endurance athletes at risk of low energy availability [Low Energy Availability in Females Questionnaire (LEAF-Q) score ≥8]. Female endurance athletes from Norway (n = 60), Sweden (n = 84), Ireland (n = 17), and Germany (n = 47) were recruited. Fifty athletes with risk of REDs (LEAF-Q score ≥8) and with low risk of eating disorders [Eating Disorder Examination Questionnaire (EDE-Q) global score <2.5], with no use of hormonal contraceptives and no chronic diseases, were allocated to either the FUEL intervention (n = 32) (FUEL) or a sixteen-week control period (n = 18) (CON). All but one completed FUEL and n = 15 completed CON. While no evidence for difference in change in LEAF-Q total or subscale scores between groups was detected post-intervention (BF_incl < 1), the 6- and 12-months follow-up revealed strong evidence for improved LEAF-Q total (BF_incl = 123) and menstrual score (BF_incl = 840) and weak evidence for improved GI-score (BF_incl = 2.3) among FUEL athletes. In addition, differences in change between groups was found for EDE-Q global score post-intervention (BF_incl= 1.9). The reduction in EDE-Q score remained at 6- and 12- months follow-up among FUEL athletes. Therefore, the FUEL intervention may improve REDs related symptoms in female endurance athletes.Clinical Trial Registration: www.clinicaltrials.gov (NCT04959565).

Introduction: Based on a mixed methods design, we investigated the experiences and evaluations of female endurance athletes at risk of REDs who participated in the FUEL intervention programme. Methods: Eighty-two percent of the FUEL participants filled out an evaluation questionnaire, and ten participated in a semi-structured interview. The quantitative data were analysed using a Bayesian Mann-Whitney test, while a critical realist approach was used to analyse the qualitative data. Results: The overall satisfaction rate (from 1 to 10) was 9.1 ± 1.1, with weak evidence for a higher satisfaction level among the FUEL_combined (16 digital lectures and 8 individual consultations) compared to FUEL_lectures (16 digital lectures) participants (9.3 ± 0.9 versus 8.0 ± 1.5, BF₁₀=1.00). Most of the participants found the duration and frequency of the consultations appropriate and did not find the digital format limiting. These results were supported by the qualitative findings showing that the participants expressed educative and motivating experiences. They also appreciated the 16-week intervention duration providing the opportunity to absorb new knowledge, implement it in their daily routines, become more body conscious, and reflect on their new positive bodily experiences. Conclusion: The participants in this multicenter study were satisfied with the FUEL intervention expressing their intentions to recommend it to other athletes and their entourage. They also highlighted the time given to acquire new knowledge, being able to reflect on their positive bodily experiences, and positively change their mindsets. Our findings may be of value for future studies developing highly needed sports nutrition interventions for the prevention of REDs at all levels.

Introduction Endurance athletes with high training loads and weight focus have increased risk of low energy and carbohydrate (CHO) availability. This is the first study aiming to investigate the timing of CHO intake in relation to training load in athletes with symptoms of relative energy deficiency in sport (RED-S). Materials and Methods Female endurance athletes (n=12) (25.9 ± 4.4) years, BMI 20.9 ± 2.1), with symptoms of RED-S (Low Energy Availability in Females Questionnaire total score 11.9 ± 2.9) without disordered eating behavior, performed a 7-day weighed dietary and training registration (heart rate monitors, online training logs). CHO intake was analyzed for key (high intensity/>120 min) and easy training sessions (all other sessions >30 min) as well as hard (including >1 key session) and light training days (all other days). Mean difference, 95% confidence intervals (CI) not including 0, and a paired student t-test were used to determine differences between CHO intake and international sport nutrition recommendations. Results None of the participants met the recommended daily CHO intake [CI -1.7 (-2.4 to -0.9)], or CHO intake immediate after [CI -0.7 (-0.9 to -0.5)], between [CI -1.2 (-2.0 to -0.4)] or during [CI -15.2 (-29.1 to -1.3)] key training sessions. CHO recommendations were more difficult to fulfill during hard compared to light training days (p=0.014). Conclusion Female endurance athletes with symptoms of RED-S have difficulties matching CHO intake in relation to training load according to the recommendations. Hence, to prevent RED-S focus on optimizing CHO intake is needed.