Review: questionnaires as measures for low energy availability (LEA) and relative energy deficiency in sport (RED-S) in athletes

A sustained mismatch between energy intake and exercise energy expenditure (EEE) can lead to Low Energy Availability (LEA), health and performance impairments characteristic of Relative Energy Deficiency in Sport (RED-S). Questionnaires can conveniently identify symptoms and/or LEA/ RED-S risk factors. This study aimed to systematically identify, and critique questionnaires used or developed to measure LEA/ RED-S risk in athletic populations. A systematic search was conducted using PubMed database. Full text articles were included if: (i) the questionnaire(s) in the study identified LEA and/or RED-S risk; (ii) studies developed questionnaires to identify LEA and/or RED-S risk; (iii) participants belonged to athletic population(s); and (iv) in English. Thirty-three articles met the inclusion criteria and were reviewed, 13 questionnaires were identified. Eight questionnaires had undergone validation procedures, and three questionnaires included questions related to EEE. The most widely used validated questionnaires were Low Energy Availability in Females Questionnaire (LEAF-Q) (48% articles) and Eating Disorder Examination Questionnaire (EDE-Q) (12% articles). The LEAF-Q determines LEA risk from symptoms but cannot be used in males as nearly half of the items (n = 12) relate to menstrual function. The EDE-Q serves as a surrogate marker of LEA risk in both sexes, as it measures a major risk factor of LEA, disordered eating. Better validation is needed for many questionnaires and more are needed to address LEA/RED-S risk in male athletes. These questionnaires may be effective in identifying intentional energy restriction but less valuable in identifying inadvertently failure to increase energy intake with increased EEE.