High-Dose Medium-Term HMB Supplementation did not Trigger Body Composition Changes in Trained and Untrained Males Under Usual Conditions or High-Intensity Functional Exercise

Krzysztof Durkalec-Michalski^1,2,3*Magdalena Czlapka-Matyasik⁴Tomasz Podgórski^5,6Małgorzata Marchelek-Myśliwiec⁷Paulina Malgorzata Nowaczyk^1,2,6

• ¹Department of Sports Dietetics, Poznan University of Physical Education, Poznań, Poland
• ²Polish Society of Nutritional Sciences, Poland, Warsaw, Poland
• ³Sport Sciences–Biomedical Department, Faculty of Physical Education and Sport, Charles University, Prague, Czechia
• ⁴Department of Human Nutrition and Dietetics, Poznań University of Life Sciences, Poznań, Poland
• ⁵Department of Biochemistry, Poznan University of Physical Education, Poznań, Poland
• ⁶Sport Sciences–Biomedical Department, Faculty of Physical Education and Sport, Charles University, Prague, Czechia
• ⁷Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland

Introduction: β-hydroxy-β-methylbutyrate (HMB) supplementation may support fat-free mass (FFM) increase and fat mass (FM) decrease. Its utility has been studied mainly for 3 gHMB·day-1, and long-term supplementation (e.g. 12 weeks). Therefore new and personalized effective HMB supplementation protocols should be verified. Methods: Ninety trained (TR, n=53; 29.1±7.7 years; FFM: 84.1±5.1%) and untrained (UTR, n=37; 32.3±7.6 years; FFM: 75.7±7.7%) males completed the randomized parallel-group placebo(PLA)-controlled study aiming at evaluation of the influence of new individualized high-dose mid-term liquid HMB free acid supplementation protocol (90mgHMB· kgFFM·day-1) – alone (3 weeks; first period) and combined with high-intensity functional training (HIFT; 3 weeks; second period) on body mass (BM), FFM and FM and total body water (TBW). The Fight Gone Bad (FGB) workout was an additional HIFT stimuli (2 units·week-1). Testing was performed at baseline (BAS), after the first (SUP), and the second (SUP+FGB) study periods. Results: HMB doses were 4.8–7.8 gHMB·day-1. The intervention had no significant effect on BM, FFM, FM or TBW changes. BM, FFM (kg), TBW, and TBW/FFM were higher at SUP+FGB vs. BAS regardless implemented treatment and training status. Nevertheless, there was impact (p<0.05) of training status (but not HMB/PLA) on FM (kg; slight increases in UTR) and TBW (slight decreases in UTR) changes. Discussion: The individually adjusted high HMB dose did not change body mass and composition in trained and untrained individuals during 3-week exclusive supplementation or 3-week supplementation in combination with additional HIFT stimuli. Therefore, any modifications in this area may likely require a longer treatment period.