Low or reduced energy availability (LEA) is linked to functional hypothalamic oligomenorrhea/amenorrhea (FHA), which is frequently reported in weight-sensitive sports. This makes LEA a major nutritional concern for female athletes. The aim of this study was to describe dietary characteristics of athletes with LEA and/or FHA. Endurance athletes (n=45) were recruited from national teams and competitive clubs. Protocols included gynecological examination, body composition, eating disorder evaluation, and 7-day dietary intake and EA assessment. Athletes with disordered eating behavior/eating disorders (n=11), menstrual dysfunction other than FHA (n=5), and low dietary record validity (n=4) were excluded. Remaining subjects (n=25) were characterized by EA [optimal:45kcal (188kJ)/kg fat-free mass (FFM)/day (n=11), LEA:<45kcal (188kJ)/kg FFM/day (n=14)] and reproductive function [eumenorrhea (EUM; n=10), FHA (n=15)]. There was no difference in EA between FHA and EUM subjects. However, FHA and LEA subjects shared the same dietary characteristics of lower energy density (ED) [(P=0.012; P=0.020), respectively], and fat content [(P=0.047; P=0.027), respectively]. Furthermore, FHA subjects had a lower intake of carbohydrate-rich foods (P=0.019), higher fiber content (P<0.001), and drive for thinness score (P=0.003). Conclusively, low ED together with high fiber content may constitute targets for dietary intervention in order to prevent and treat LEA and FHA in female athletes.