13C-glucose-fructose labelling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew or co-ingestion

Hearris, MA, Pugh, JN, Langan-Evans, C, Mann, SJ, Burke, L, Stellingwerff, T, Gonzalez, JT and Morton, JP ORCID: 0000-0003-2776-2542 (2022) 13C-glucose-fructose labelling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew or co-ingestion. Journal of applied physiology, 132 (6). pp. 1394-1406. ISSN 8750-7587

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Abstract

We examined the effects of carbohydrate (CHO) delivery form on exogenous CHO oxidation, gastrointestinal discomfort, and exercise capacity. In a randomised repeated measures design (after 24 h of high CHO intake (8 g·kg-1) and pre-exercise meal (2 g·kg-1)), nine trained males ingested 120 g CHO·h-1 from fluid (DRINK), semi-solid gel (GEL), solid jelly chew (CHEW), or a co-ingestion approach (MIX). Participants cycled for 180 min at 95% lactate threshold followed by an exercise capacity test (150% lactate threshold). Peak rates of exogenous CHO oxidation (DRINK, 1.56 ± 0.16; GEL, 1.58 ± 0.13; CHEW, 1.59 ± 0.08; MIX, 1.66 ± 0.02 g·min-1) and oxidation efficiency (DRINK, 72 ± 8; GEL, 72 ± 5; CHEW, 75 ± 5; MIX, 75 ± 6%) were not different between trials (all P > 0.05). Despite ingesting 120 g·h-1, participants reported minimal symptoms of gastrointestinal distress across all trials. Exercise capacity was also not significantly different (all P < 0.05) between conditions (DRINK, 446 ± 350; GEL, 529 ± 396; CHEW, 596 ± 416; MIX, 469 ± 395 sec). Data represent the first time that rates of exogenous CHO oxidation (via stable isotope methodology) have been simultaneously assessed using feeding strategies (i.e., pre-exercise CHO feeding and the different forms and combinations of CHO during exercise) commonly adopted by elite endurance athletes. We conclude 120 g·h-1 CHO (in a 1:0.8 ratio of maltodextrin or glucose:fructose) is a practically tolerable strategy to promote high CHO availability and oxidation during exercise.

Item Type:	Article
Uncontrolled Keywords:	Stable isotopes; fructose; maltodextrin; metabolism; Physiology; 06 Biological Sciences; 11 Medical and Health Sciences
Subjects:	T Technology > TX Home economics > TX341 Nutrition. Foods and food supply R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport and Exercise Sciences
Publisher:	American Physiological Society
Date of acceptance:	14 April 2022
Date of first compliant Open Access:	1 June 2023
Date Deposited:	26 Apr 2022 09:51
Last Modified:	05 Jul 2025 16:30
DOI or ID number:	10.1152/japplphysiol.00091.2022
URI:	https://researchonline.ljmu.ac.uk/id/eprint/16713

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