Introduction
To optimize nutritional counseling for Paralympic athletes, advanced insight into the athletes’ energy demands is required. The current study is a comprehensive assessment of energy expenditure along with energy intake (EI) and body composition in a large group of Paralympic athletes.

Methods
In this ongoing cross-sectional study, 39 Dutch and Norwegian Paralympic athletes with various disabilities and competing in various sports (Para cycling PC n=9; Wheelchair tennis WCT n=10; Wheelchair basketball WCB n=13; Cross-country skiing XCS n=7) participated. Total daily energy expenditure (TDEE) was assessed by the doubly labeled water method over a 14-day period, resting metabolic rate (RMR) by indirect calorimetry, EI by three 24h-dietary recalls, body composition by dual energy x-ray absorptiometry and exercise training duration by a training log. The physical activity level (PAL) was calculated as TDEE/RMR and energy availability (EA) was calculated as (EI-(TDEE-RMR-0.1EI))/fat free mass (FFM). Data are reported as means±SD. Differences between sports were conducted by one-way ANOVA with Bonferroni correction and correlations by a Pearson correlation test.

Results
The TDEE differed between sports, with PC (3691±826 kcal/day) and WCT (3082±381 kcal/day) showing substantially higher TDEE compared with WCB (2301±347 kcal/day; p<0.05), but not compared with XCS (2903±541 kcal/day). The RMR (1482±257 kcal/day) correlated well with FFM (48.8±9.3 kg; r=0.76; p<0.001), while PAL values (1.98±0.33) correlated well with exercise training duration (1.83±0.64 h/day; r=0.51; p=0.006). When considering athletes’ EI (2397±961 kcal/day), 67% of the athletes were classified as low EA (<30 kcal/kg FFM).

Conclusion
Paralympic athletes experience high daily energy demands, with many athletes exceeding a PAL value of 2.0. Much of the variation in energy expenditure between sports and individuals can be explained by differences in fat free mass and exercise training load. The substantial energy demands of Paralympic athletes underline the need to prevent low energy availability in this population.