Reducing energy availability in male endurance athletes: a randomized trial with a three-step energy reduction

Does Relative Energy Deficiency in Sport (REDs) Syndrome Exist?

Relative energy deficiency in sport (REDs) is a widely adopted model, originally proposed by an International Olympic Committee (IOC) expert panel in 2014 and recently updated in an IOC 2023 consensus statement. The model describes how low energy availability (LEA) causes a wide range of deleterious health and performance outcomes in athletes. With increasing frequency, sports practitioners are diagnosing athletes with "REDs," or "REDs syndrome," based largely upon symptom presentation. The purpose of this review is not to "debunk" REDs but to challenge dogmas and encourage rigorous scientific processes. We critically discuss the REDs concept and existing empirical evidence available to support the model. The consensus (IOC 2023) is that energy availability, which is at the core of REDs syndrome, is impossible to measure accurately enough in the field, and therefore, the only way to diagnose an athlete with REDs appears to be by studying symptom presentation and risk factors. However, the symptoms are rather generic, and the causes likely multifactorial. Here we discuss that (1) it is very difficult to isolate the effects of LEA from other potential causes of the same symptoms (in the laboratory but even more so in the field); (2) the model is grounded in the idea that one factor causes symptoms rather than a combination of factors adding up to the etiology. For example, the model does not allow for high allostatic load (psychophysiological "wear and tear") to explain the symptoms; (3) the REDs diagnosis is by definition biased because one is trying to prove that the correct diagnosis is REDs, by excluding other potential causes (referred to as differential diagnosis, although a differential diagnosis is supposed to find the cause, not demonstrate that it is a pre-determined cause); (4) observational/cross-sectional studies have typically been short duration (< 7 days) and do not address the long term "problematic LEA," as described in the IOC 2023 consensus statement; and (5) the evidence is not as convincing as it is sometimes believed to be (i.e., many practitioners believe REDs is well established). Very few studies can demonstrate causality between LEA and symptoms, most studies demonstrate associations and there is a worrying number of (narrative) reviews on the topic, relative to original research. Here we suggest that the athlete is best served by an unbiased approach that places health at the center, leaving open all possible explanations for the presented symptoms. Practitioners could use a checklist that addresses eight categories of potential causes and involve the relevant experts if and when needed. The Athlete Health and Readiness Checklist (AHaRC) we introduce here simply consists of tools that have already been developed by various expert/consensus statements to monitor and troubleshoot aspects of athlete health and performance issues. Isolating the purported effects of LEA from the myriad of other potential causes of REDs symptoms is experimentally challenging. This renders the REDs model somewhat immune to falsification and we may never definitively answer the question, "does REDs syndrome exist?" From a practical point of view, it is not necessary to isolate LEA as a cause because all potential areas of health and performance improvement should be identified and tackled.

Low energy availability surrogates are associated with Relative Energy Deficiency in Sport outcomes in male athletes

OBJECTIVES

To determine the association between surrogates of low energy availability (EA) and proposed health and performance outcomes of Relative Energy Deficiency in Sport (REDs) in a clinical sample of adolescent and young adult male athletes.

METHODS

Male athletes ages 15-30 years presenting to a sports medicine clinic at two tertiary care centres were invited to complete a survey about athlete health and well-being. Participants were divided into low EA and adequate EA groups based on survey responses. The associations between low EA and REDs outcomes were evaluated using χ2 tests and ORs were calculated using binomial logistic regression (significance: p<0.05).

RESULTS

Low EA was associated with increased frequency of self-reported immunological, metabolic, psychological, cardiovascular and gastrointestinal dysfunction; reduced endurance performance, response to training, judgement, coordination and muscle strength; and increased irritability and depression. Low EA athletes were more likely to have self-reported cardiovascular dysfunction (OR 2.87, 95% CI 1.56 to 5.26) and psychological illness (OR 3.23, 95% CI 1.91 to 5.41), decreased training response (OR 2.64, 95% CI 1.38 to 5.03) and endurance performance (OR 2.26, 95% CI 1.13 to 4.52) and were less likely to have self-reported gonadal dysfunction (OR 0.49, 95% CI 0.30 to 0.81), than adequate EA athletes (p<0.05).

CONCLUSIONS

Low EA surrogates are associated with many adverse health outcomes and performance effects of REDs in male athletes. More prospective REDs research in males is needed to improve various aspects of REDs screening in young male athletes.

Dietary intake, energy availability, and power in men collegiate gymnasts

Introduction

The purpose was to examine the prevalence of low energy availability (LEA), explore dietary behaviors in men collegiate gymnasts (n = 14), and investigate the relationships between energy availability (EA), body composition, and plyometric performance.

Methods

Body composition was measured using air displacement plethysmography. Lower- and upper-body peak power (PWRpeak) and modified reactive strength index (RSImod) were calculated from countermovement jump (CMJ) and plyometric push-up (PP) assessments. Energy expenditure was tracked over 3 days, while daily energy and macronutrient intake were recorded. EA was calculated and used to categorize athletes into LEA and non-LEA groups. Pearson correlation coefficients were used to examine relationships between EA, body composition, and performance metrics.

Results

85.7% of athletes (n = 12) exhibited LEA (20.98 ± 5.2 kcals/kg FFM), with non-LEA athletes (n = 2) marginally surpassing the <30 kcal/kg of fat-free mass (FFM) threshold (30.58 ± 0.2 kcals/kg FFM). The cohort (n = 14) consumed insufficient energy (30.5 ± 4.5 kcal/kg/day) and carbohydrates (3.7 ± 1.1 g/kg/day), resulting in LEA (22.36 ± 5.9 kcal/kg/FFM). EA was not correlated with body composition or performance metrics.

Discussion

A high prevalence of LEA may exist in men gymnasts, largely due to a low relative energy and carbohydrate intake.

Relationship between fat-free mass index and nutrient intake in protein supplement user among Japanese collegiate soccer athletes

PURPOSE

Protein supplements are widely used by athletes, prompting the scrutiny of their impact on low energy availability. This study investigated whether habitual protein supplement use is linked to physical characteristics and nutrient intake in Japanese university soccer athletes. In addition, an attempt was made to examine the differences in physical characteristics and nutrient intake according to muscle mass in protein supplement users using the fat-free mass index (FFMI), which reflects muscle mass.

METHODS

A dietary survey, physical activity survey, and measurement of the physical characteristics of 38 Japanese collegiate soccer players were conducted.

RESULTS

The habitual protein supplement utilization rate among the participants was 50%, and the participants exhibited an FFMI of 19.2 ± 1.3 kg/m2. Significant disparities between the two groups were noted in exercise energy expenditure (p = 0.023); carbohydrates (p = 0.039); copper (p = 0.003); and vitamins B1 (p = 0.016), B2 (p = 0.040), B6 (p = 0.003), C (p = 0.012), and D (p = 0.033), with higher levels observed in the protein-consuming cohort compared to the non-consuming cohort. Protein supplement users (n = 15) were stratified into two groups based on the median FFMI of the entire population (18.9 kg/m2). While the energy balance ratios were comparable between the groups, the high FFMI group tended to exhibit elevated energy intake (p = 0.169), consumption (p = 0.076), and carbohydrate consumption (p = 0.092), compared to the low FFMI group.

CONCLUSION

These findings suggest that adequate carbohydrate and protein intakes are crucial for preserving or augmenting muscle mass in young Japanese soccer athletes, including those consuming protein supplements.

Identifying and Analyzing Low Energy Availability in Athletes: The Role of Biomarkers and Red Blood Cell Turnover

Low energy availability (LEA) is a growing concern that can lead to several problems for athletes. However, adaptation to LEA occurs to maintain balance over time, making diagnosis difficult. In this review, we categorize LEA into two phases: the initial phase leading to adaptation and the phase in which adaptation is achieved and maintained. We review the influence of LEA on sports performance and health and discuss biomarkers for diagnosing LEA in each phase. This review also proposes future research topics for diagnosing LEA, with an emphasis on the recently discovered association between red blood cell turnover and LEA.

Energy Availability and Interstitial Fluid Glucose Changes in Elite Male Japanese Triathletes during Training Camp: A Case Study

This study explored the impact of varying energy availability (EA) on the 24-h interstitial fluid glucose concentration (IGC) in five elite male Japanese triathletes at a training camp. Measurements of IGC, energy and macronutrient intake, and exercise energy expenditure (EEE) through metabolic equivalents (METs) from training logs were conducted. Three subjects were evaluated over two 4-day periods, and two subjects over one 4-day period. Findings revealed significant correlations of daily mean nocturnal IGC with daily EA (r = 0.553, p = 0.001) and energy intake (EI) (r = 0.595, p < 0.001). However, no significant correlation was found between mean daily nocturnal IGC and EEE (r = -0.278, p = 0.124). Daytime IGC was ≥110 mg/dL for >50% of the time in all subjects, except on 1 day in one subject, and never fell <70 mg/dL. Therefore, daily EA may influence nocturnal IGC in elite male triathletes, although high daytime IGC levels were maintained without hypoglycemia.

A real-life snapshot: Evaluating exposures to low energy availability in male athletes from various sports

Problematic low energy availability (LEA) is the underlying cause of relative energy deficiency in sport (REDs). Male specific etiology, as well as the duration and degree of LEA exposures resulting in REDs remain to be adequately described. The present study aimed to assess occurrences of LEA (energy availability [EA] <25 kcal/kg fat-free mass/day) in male athletes from various sports over 7 days. Associations between number of LEA days, physiological measures, and body image concerns were subsequently evaluated. The athletes recorded their weighed food intakes and training via photo-assisted mobile application. Body composition and resting metabolic rates were measured, and venous blood samples collected for assessments of hormonal and nutrition status. Participants also answered the Low Energy Availability in Males Questionnaire (LEAM-Q), Eating Disorder Examination-Questionnaire Short (EDE-QS), Exercise Addiction Inventory (EAI), and Muscle Dysmorphic Disorder Inventory (MDDI). Of 19 participants, 13 had 0-2, 6 had 3-5, and none had 6-7 LEA days. No associations were found between the number of LEA days with the physiological and body image outcomes, although those with greatest number of LEA days had highest EEE but relatively low dietary intakes. In conclusion, this group displayed considerable day-to-day EA fluctuations but no indication of problematic LEA.

Low Energy Availability Followed by Optimal Energy Availability Does Not Benefit Performance in Trained Females

PURPOSE

Short periods of reduced energy availability are commonly undertaken by athletes to decrease body mass, possibly improve the power-to-mass ratio, and enhance physical performance. Our primary aim was to investigate the impact of 10 d of low energy availability (LEA) followed by 2 d of optimal energy availability (OEA) on physical performance parameters in trained females. Second, physiological markers at the whole-body and molecular level related to performance were evaluated.

METHODS

Thirty young trained eumenorrheic females were matched in pairs based on training history and randomized to a 10-d intervention period of LEA (25 kcal·fat-free mass (FFM) -1 ·d -1 ) or OEA (50 kcal·FFM -1 ·d -1 ) along with supervised exercise training. Before the intervention, participants underwent a 5-d run-in period with OEA + supervised exercise training. After the LEA intervention, 2 d of recovery with OEA was completed. Participants underwent muscle biopsies, blood sampling, physical performance tests, body composition measurements, and resting metabolic rate measurements. A linear mixed model was used with group and time as fixed effects and subject as random effects.

RESULTS

Compared with OEA, LEA resulted in reduced body mass, muscle glycogen content, repeated sprint ability, 4-min time-trial performance, and rate of force development of the knee extensors (absolute values; P < 0.05). Two days of recovery restored 4-min time-trial performance and partly restored repeated sprint ability, but performance remained inferior to the OEA group. When the performance data were expressed relative to body mass, LEA did not enhance performance.

CONCLUSIONS

Ten days of LEA resulted in impaired performance (absolute values), with concomitant reductions in muscle glycogen. Two days of recovery with OEA partially restored these impairments, although physical performance (absolute values) was still inferior to being in OEA. Our findings do not support the thesis that LEA giving rise to small reductions in body mass improves the power-to-mass ratio and thus increases physical performance.

Direct and indirect impact of low energy availability on sports performance

Low energy availability (LEA) occurs inadvertently and purposefully in many athletes across numerous sports; and well planned, supervised periods with moderate LEA can improve body composition and power to weight ratio possibly enhancing performance in some sports. LEA however has the potential to have negative effects on a multitude of physiological and psychological systems in female and male athletes. Systems such as the endocrine, cardiovascular, metabolism, reproductive, immune, mental perception, and motivation as well as behaviors can all be impacted by severe (serious and/or prolonged or chronic) LEA. Such widely diverse effects can influence the health status, training adaptation, and performance outcomes of athletes leading to both direct changes (e.g., decreased strength and endurance) as well as indirect changes (e.g., reduced training response, increased risk of injury) in performance. To date, performance implications have not been well examined relative to LEA. Therefore, the intent of this narrative review is to characterize the effects of short-, medium-, and long-term exposure to LEA on direct and indirect sports performance outcomes. In doing so we have focused both on laboratory settings as well as descriptive athletic case-study-type experiential evidence.

Relative Energy Deficiency in Sport (REDs) Indicators in Male Adolescent Endurance Athletes: A 3-Year Longitudinal Study

Longitudinal measurements of Relative Energy Deficiency in Sport (REDs) among adolescent male elite athletes are lacking. We aimed to monitor REDs indicators and their possible impact on performance in elite high-school cross-country skiing and biathlon athletes (n = 13) (16.3 ± 0.4 years, 179.4 ± 7.6 cm, 63.6 ± 8.2 kg body mass (BM), and peak oxygen uptake (VO2peak): 61.5 ± 5.3 mL/kg BM/min) every 6 months for 3 years. Protocols included assessments of energy availability (EA), body composition and bone mineral density (BMD), resting metabolic rate (RMR), disordered eating behavior, exercise addiction, VO2peak, and muscle strength. Data were analyzed using a linear mixed model. At baseline, 38% had low lumbar BMD (Z-score ≤ -1), and overall, bone health increased only slightly. VO2peak and muscle strength improved (p < 0.001), RMR decreased (p = 0.016), and no change was observed in EA or physiological or psychological REDs indicators. Conclusively, many of these young male athletes had poor bone health at baseline, and most either lost or did not achieve the expected pubertal bone mineral accrual, although no other indication of REDs was observed, while performance improved during the study period. Our findings highlight the importance of elite sports high schools focusing on screening for early detection of impaired bone health in male athletes.

Male Runners With Lower Energy Availability Have Impaired Skeletal Integrity Compared to Nonathletes

CONTEXT

Female athletes, particularly runners, with insufficient caloric intake for their energy expenditure [low energy availability (EA) or relative energy deficiency] are at risk for impaired skeletal integrity. Data are lacking in male runners.

OBJECTIVE

To determine whether male runners at risk for energy deficit have impaired bone mineral density (BMD), microarchitecture, and estimated strength.

DESIGN

Cross-sectional.

SETTING

Clinical research center.

PARTICIPANTS

39 men (20 runners, 19 controls), ages 16-30 years.

MAIN OUTCOME MEASURES

Areal BMD (dual-energy x-ray absorptiometry); tibia and radius volumetric BMD and microarchitecture (high-resolution peripheral quantitative computed tomography); failure load (microfinite element analysis); serum testosterone, estradiol, leptin; energy availability.

RESULTS

Mean age (24.5 ± 3.8 y), lean mass, testosterone, and estradiol levels were similar; body mass index, percent fat mass, leptin, and lumbar spine BMD Z-score (-1.4 ± 0.8 vs -0.8 ± 0.8) lower (P < .05); and calcium intake and running mileage higher (P ≤ .01) in runners vs controls. Runners with EA

CONCLUSIONS

Despite weight-bearing activity, skeletal integrity is impaired in male runners with lower caloric intake relative to exercise energy expenditure, which may increase bone stress injury risk. Lower estradiol and lean mass are associated with lower tibial strength in runners.

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Key Words

• HR-pQCT
• athletes
• bone density
• energy availability

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MESH Headings

• Humans
• Male
• Female
• Leptin
• Cross-Sectional Studies
• Calcium
• Bone Density
• Absorptiometry, Photon
• Lumbar Vertebrae
• Testosterone
• Estradiol

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Grants

• K23 DK115903 NIDDK NIH HHS
• K24 HD071843 NICHD NIH HHS
• 1UL1TR002541-01 NIH HHS
• K24 HL092902 NHLBI NIH HHS
• Massachusetts General Hospital Executive Committee on Research
• National Institutes of Health
• Department of Defense Research Participation Program
• U.S. Army Research Institute of Environmental Medicine
• Oak Ridge Institute for Science and Education

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Affiliation(s)

Melanie S Haines Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Harvard Medical School, Boston, MA 02115, USA
Snimarjot Kaur Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Harvard Medical School, Boston, MA 02115, USA
Geetanjali Scarff Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
Meghan Lauze Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
Anu Gerweck Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
Meghan Slattery Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
Nicolas M Oreskovic Harvard Medical School, Boston, MA 02115, USA Department of Internal Medicine and Pediatrics, Massachusetts General Hospital, Boston, MA 02114, USA
Kathryn E Ackerman Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Harvard Medical School, Boston, MA 02115, USA Female Athlete Program, Division of Sports Medicine, Boston Children's Hospital, Boston, MA 02115, USA
Adam S Tenforde Harvard Medical School, Boston, MA 02115, USA Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Cambridge, MA 02129, USA
Kristin L Popp Harvard Medical School, Boston, MA 02115, USA Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA Department of Energy, Oak Ridge Institute for Science and Education, Oak Ridge, TN 37830, USA
Mary L Bouxsein Harvard Medical School, Boston, MA 02115, USA Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
Karen K Miller Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Harvard Medical School, Boston, MA 02115, USA
Madhusmita Misra Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA Harvard Medical School, Boston, MA 02115, USA Division of Pediatric Endocrinology, Massachusetts General Hospital, Boston, MA 02114, USA

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Review of the scientific rationale, development and validation of the International Olympic Committee Relative Energy Deficiency in Sport Clinical Assessment Tool: V.2 (IOC REDs CAT2)-by a subgroup of the IOC consensus on REDs

Relative Energy Deficiency in Sport (REDs) has various different risk factors, numerous signs and symptoms and is heavily influenced by one's environment. Accordingly, there is no singular validated diagnostic test. This 2023 International Olympic Committee's REDs Clinical Assessment Tool-V.2 (IOC REDs CAT2) implements a three-step process of: (1) initial screening; (2) severity/risk stratification based on any identified REDs signs/symptoms (primary and secondary indicators) and (3) a physician-led final diagnosis and treatment plan developed with the athlete, coach and their entire health and performance team. The CAT2 also introduces a more clinically nuanced four-level traffic-light (green, yellow, orange and red) severity/risk stratification with associated sport participation guidelines. Various REDs primary and secondary indicators have been identified and 'weighted' in terms of scientific support, clinical severity/risk and methodological validity and usability, allowing for objective scoring of athletes based on the presence or absence of each indicator. Early draft versions of the CAT2 were developed with associated athlete-testing, feedback and refinement, followed by REDs expert validation via voting statements (ie, online questionnaire to assess agreement on each indicator). Physician and practitioner validity and usability assessments were also implemented. The aim of the IOC REDs CAT2 is to assist qualified clinical professionals in the early and accurate diagnosis of REDs, with an appropriate clinical severity and risk assessment, in order to protect athlete health and prevent prolonged and irreversible outcomes of REDs.

2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)

Relative Energy Deficiency in Sport (REDs) was first introduced in 2014 by the International Olympic Committee's expert writing panel, identifying a syndrome of deleterious health and performance outcomes experienced by female and male athletes exposed to low energy availability (LEA; inadequate energy intake in relation to exercise energy expenditure). Since the 2018 REDs consensus, there have been >170 original research publications advancing the field of REDs science, including emerging data demonstrating the growing role of low carbohydrate availability, further evidence of the interplay between mental health and REDs and more data elucidating the impact of LEA in males. Our knowledge of REDs signs and symptoms has resulted in updated Health and Performance Conceptual Models and the development of a novel Physiological Model. This Physiological Model is designed to demonstrate the complexity of either problematic or adaptable LEA exposure, coupled with individual moderating factors, leading to changes in health and performance outcomes. Guidelines for safe and effective body composition assessment to help prevent REDs are also outlined. A new REDs Clinical Assessment Tool-Version 2 is introduced to facilitate the detection and clinical diagnosis of REDs based on accumulated severity and risk stratification, with associated training and competition recommendations. Prevention and treatment principles of REDs are presented to encourage best practices for sports organisations and clinicians. Finally, methodological best practices for REDs research are outlined to stimulate future high-quality research to address important knowledge gaps.

Mapping the complexities of Relative Energy Deficiency in Sport (REDs): development of a physiological model by a subgroup of the International Olympic Committee (IOC) Consensus on REDs

The 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs) notes that exposure to low energy availability (LEA) exists on a continuum between adaptable and problematic LEA, with a range of potential effects on both health and performance. However, there is variability in the outcomes of LEA exposure between and among individuals as well as the specific manifestations of REDs. We outline a framework for a 'systems biology' examination of the effect of LEA on individual body systems, with the eventual goal of creating an integrated map of body system interactions. We provide a template that systematically identifies characteristics of LEA exposure (eg, magnitude, duration, origin) and a variety of moderating factors (eg, medical history, diet and training characteristics) that could exacerbate or attenuate the type and severity of impairments to health and performance faced by an individual athlete. The REDs Physiological Model may assist the diagnosis of underlying causes of problems associated with LEA, with a personalised and nuanced treatment plan promoting compliance and treatment efficacy. It could also be used in the strategic prevention of REDs by drawing attention to scenarios of LEA in which impairments of health and performance are most likely, based on knowledge of the characteristics of the LEA exposure or moderating factors that may increase the risk of harmful outcomes. We challenge researchers and practitioners to create a unifying and dynamic physiological model for each body system that can be continuously updated and mapped as knowledge is gained.

The Influence of Energy Balance and Availability on Resting Metabolic Rate: Implications for Assessment and Future Research Directions

Resting metabolic rate (RMR) is a significant contributor to an individual's total energy expenditure. As such, RMR plays an important role in body weight regulation across populations ranging from inactive individuals to athletes. In addition, RMR may also be used to screen for low energy availability and energy deficiency in athletes, and thus may be useful in identifying individuals at risk for the deleterious consequences of chronic energy deficiency. Given its importance in both clinical and research settings within the fields of exercise physiology, dietetics, and sports medicine, the valid assessment of RMR is critical. However, factors including varying states of energy balance (both short- and long-term energy deficit or surplus), energy availability, and prior food intake or exercise may influence resulting RMR measures, potentially introducing error into observed values. The purpose of this review is to summarize the relationships between short- and long-term changes in energetic status and resulting RMR measures, consider these findings in the context of relevant recommendations for RMR assessment, and provide suggestions for future research.

Energy availability and RED-S risk assessment among Kho-Kho players in India

Purpose

Energy availability (EA) is considered an important measure for athletes, particularly due to the possible health and performance outcomes defined under the RED-S. Low EA is reported to have far-reaching health consequences among female athletes, especially in weight-sensitive sport. However, it is less explored among male athletes, particularly in the traditional Indian tag sport called Kho-Kho. This cross-sectional observational study aimed to determine the prevalence of LEA and associated RED-S health and performance outcomes among Kho-Kho players.

Methods

Fifty-two male national-level Kho-Kho players aged 16-31 years were assessed for energy availability, bone mineral density (BMD), sleep quality, disordered eating, selected metabolic (hemoglobin, blood glucose, etc.) and performance outcomes (agility, speed, and power) as per RED-S risk assessment tool. Differences across the low EA (≤ 25 kcal/ kg fat-free mass) and Optimal EA (> 25 kcal/ kg fat-free mass) groups were evaluated using the Independent Samples t test and the chi-square test.

Results

Low EA among athletes was associated with lower z-scores for BMD, sleep quality and agility, compared to athletes with optimal EA. At least one moderate-to-high RED-S risk outcome was prevalent among 98% of the Kho-Kho players, irrespective of EA. Most athletes exhibited a lower EAT score and disordered eating outcomes, with no significant differences across groups.

Conclusion

The male Kho-Kho players showed a prevalence of low EA that can be due to higher training loads and unintentional under-eating, not related to an eating disorder. The players also exhibited higher RED-S risk outcomes; however, it was irrespective of low EA.