Resting Energy Expenditure, Body Composition and Phase Angle in Anorectic, Ballet Dancers and Constitutionally Lean Males

Background: The prevalence of anorexia nervosa among males is increasing but few data are available in the literature. This cross sectional study aims to evaluate resting energy expenditure (REE) and phase angle as a marker of qualitative changes of fat free mass (FFM) in three leanness groups as compared with control subjects. Methods: 17 anorectic (AN) males, 15 constitutionally lean (CL) individuals, 12 ballet dancers (DC), and 18 control (CTR) subjects were evaluated. REE was measured by indirect calorimetry (V max29- Sensormedics), and body composition was evaluated by bioimpedance analysis (BIA) at 50 kHz (DS Medica). Phase angle (a bioimpedance variable related to nutritional status) was used to evaluate differences in FFM characteristics between these three types of leanness. Results: REE, adjusted for FFM and fat mass (FM), were significantly higher in CL and lower in AN individuals (1783 ± 47 vs. 1291 ± 58 kcal, p < 0.05) compared to the other groups. Body composition was similar in AN and CL whereas dancers had the highest FFM (58.9 ± 4.8 kg, p < 0.05); anorectic males showed the lowest phase angle (5.8 ± 1.2 degrees vs. other groups, p < 0.05) and dancers the highest phase angle (7.9 ± 0.7 degree vs. other group, p < 0.05). Conclusions: Our findings confirm that phase angle could be a useful marker of qualitative changes, above all in the field of sport activities. On the other hand, there is the need to further evaluate the relationship between resting energy expenditure, body composition and endocrine status in different conditions of physical activity and dietary intake.