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.

运动中的相对能量不足 （REDs） 是一种广泛采用的模型，最初由国际奥林匹克委员会 （IOC） 专家小组于 2014 年提出，最近在 IOC 2023 共识声明中进行了更新。该模型描述了低能量可用性 （LEA） 如何导致运动员产生广泛的有害健康和表现结果。随着频率的增加，运动从业者主要根据症状表现诊断运动员患有“REDs”或“REDs 综合征”。本综述的目的不是“揭穿”REDs，而是挑战教条并鼓励严格的科学过程。我们批判性地讨论了 REDs 概念和可用于支持该模型的现有经验证据。共识 （IOC 2023） 是能量可用性是 REDs 综合征的核心，不可能在现场足够准确地测量，因此，诊断运动员患有 REDs 的唯一方法似乎是研究症状表现和风险因素。然而，症状相当普遍，原因可能是多因素的。在这里，我们讨论 （1） 很难将 LEA 的影响与相同症状的其他潜在原因区分开来（在实验室中，但在现场更是如此）;（2） 该模型基于一个因素导致症状的想法，而不是多种因素的组合加起来导致病因。 例如，该模型不允许高异体负荷（心理生理学“磨损”）来解释症状;（3） REDs 诊断根据定义是有偏见的，因为人们试图通过排除其他潜在原因来证明正确的诊断是 REDs（称为鉴别诊断，尽管鉴别诊断应该找到原因，而不是证明它是预先确定的原因）;（4） 观察性/横断面研究通常持续时间较短（< 7 天），并且没有解决 IOC 2023 共识声明中描述的长期“有问题的 LEA”;（5） 证据并不像有时认为的那样令人信服（即，许多从业者认为 REDs 已经得到充分证实）。很少有研究可以证明 LEA 和症状之间的因果关系，大多数研究证明了关联，并且相对于原始研究，关于该主题的（叙述性）评论数量令人担忧。在这里，我们建议运动员最好采用一种公正的方法，将健康放在中心，为呈现的症状留下所有可能的解释。从业者可以使用一份清单，解决八类潜在原因，并在需要时让相关专家参与进来。我们在这里介绍的运动员健康和准备清单 （AHaRC） 仅包含各种专家/共识声明已经开发的工具，用于监控和解决运动员健康和表现问题的各个方面。将 LEA 的所谓影响与 REDs 症状的无数其他潜在原因区分开来在实验上具有挑战性。这使得 REDs 模型在某种程度上不受证伪的影响，我们可能永远无法明确回答这个问题，“REDs 综合症存在吗？“ 从实际角度来看，没有必要将 LEA 作为一个原因孤立出来，因为应该确定和解决所有潜在的健康和绩效改进领域。