Short Severe Energy Restriction with Refueling Reduces Body Mass without Altering Training-Associated Performance Improvement

Purpose: We investigated short-term (9 d) exposure to low energy availability (LEA) in elite endurance athletes during a block of intensified training on self-reported well-being, body composition, and performance. Methods: Twenty-three highly trained race walkers undertook an similar to 3-wk research-embedded training camp during which they undertook baseline testing and 6 d of high energy/carbohydrate (HCHO) availability (40 kcal & BULL;kg FFM-1 & BULL;d(-1)) before being allocated to 9 d continuation of this diet (n = 10 M, 2 F) or a significant decrease in energy availability to 15 kcal & BULL;kg FFM-1 & BULL;d(-1) (LEA: n = 10 M, 1 F). A real-world 10,000-m race walking event was undertaken before (baseline) and after (adaptation) these phases, with races being preceded by standardized carbohydrate fueling (8 g & BULL;kg body mass [BM](-1) for 24 h and 2 g & BULL;kg BM-1 prerace meal). Results: Dual-energy x-ray absorptiometry-assessed body composition showed BM loss (2.0 kg, P < 0.001), primarily due to a 1.6-kg fat mass reduction (P < 0.001) in LEA, with smaller losses (BM = 0.9 kg, P = 0.008; fat mass = 0.9 kg, P < 0.001) in HCHO. The 76-item Recovery-Stress Questionnaire for Athletes, undertaken at the end of each dietary phase, showed significant diet-trial effects for overall stress (P = 0.021), overall recovery (P = 0.024), sport-specific stress (P = 0.003), and sport-specific recovery (P = 0.012). However, improvements in race performance were similar: 4.5% & PLUSMN; 4.1% and 3.5% & PLUSMN; 1.8% for HCHO and LEA, respectively (P < 0.001). The relationship between changes in performance and prerace BM was not significant (r = -0.08 [-0.49 to 0.35], P = 0.717). Conclusions: A series of strategically timed but brief phases of substantially restricted energy availability might achieve ideal race weight as part of a long-term periodization of physique by high-performance athletes, but the relationship between BM, training quality, and performance in weight-dependent endurance sports is complicated.

Automated summary

The purpose of this study was to investigate the effects of short-term exposure to low energy availability (LEA) on well-being, body composition, and performance in elite endurance athletes during intensified training. The results showed that the LEA group had greater reductions in body weight and fat mass, but no significant differences in race performance were observed between the two groups. Additionally, there were no significant differences in recovery and stress levels between the groups.