The Effects of an Acute "Train-Low" Nutritional Protocol on Markers of Recovery Optimization in Endurance-Trained Male Athletes

• Published in: International journal of sports physiology and performance Vol. 16; no. 12; p. 1764
• Main Authors: Russo, Isabella, Della Gatta, Paul A, Garnham, Andrew, Porter, Judi, Burke, Louise M, Costa, Ricardo J S
• Format: Journal Article
• Language: English
• Published: United States 01.12.2021
• Subjects: Athletes; Cross-Over Studies; Dietary Carbohydrates - metabolism; Double-Blind Method; Glycogen Synthase Kinase 3 beta - metabolism; Glycogen Synthase Kinase 3 beta - pharmacology; Humans; Male; Muscle, Skeletal - physiology; Physical Endurance - physiology; gastrointestinal; immune; glycogen; hydration; carbohydrate; protein
• ISSN: 1555-0273
• DOI: 10.1123/ijspp.2020-0847

This study aimed to determine the effects of an acute "train-low" nutritional protocol on markers of recovery optimization compared to standard recovery nutrition protocol. After completing a 2-hour high-intensity interval running protocol, 8 male endurance athletes consumed a standard dairy milk recovery beverage (CHO; 1.2 g/kg body mass [BM] of carbohydrate and 0.4 g/kg BM of protein) and a low-carbohydrate (L-CHO; isovolumetric with 0.35 g/kg BM of carbohydrate and 0.5 g/kg BM of protein) dairy milk beverage in a double-blind randomized crossover design. Venous blood and breath samples, nude BM, body water, and gastrointestinal symptom measurements were collected preexercise and during recovery. Muscle biopsy was performed at 0 hour and 2 hours of recovery. Participants returned to the laboratory the following morning to measure energy substrate oxidation and perform a 1-hour distance test. The exercise protocol resulted in depletion of muscle glycogen stores (250 mmol/kg dry weight) and mild body-water losses (BM loss = 1.8%). Neither recovery beverage replenished muscle glycogen stores (279 mmol/kg dry weight) or prevented a decrease in bacterially stimulated neutrophil function (-21%). Both recovery beverages increased phosphorylation of mTORSer2448 (main effect of time = P < .001) and returned hydration status to baseline. A greater fold increase in p-GSK-3βSer9/total-GSK-3β occurred on CHO (P = .012). Blood glucose (P = .005) and insulin (P = .012) responses were significantly greater on CHO (618 mmol/L per 2 h and 3507 μIU/mL per 2 h, respectively) compared to L-CHO (559 mmol/L per 2 h and 1147 μIU/mL per 2 h, respectively). Rates of total fat oxidation were greater on CHO, but performance was not affected. A lower-carbohydrate recovery beverage consumed after exercise in a "train-low" nutritional protocol does not negatively impact recovery optimization outcomes.