NCT05241730: GI

Glycaemic Index and Substrate Metabolism

Completed NA Last updated 27 November 2023

What this trial tests

NA trial testing Training intervention in Substrate Metabolism During Exercise in 65 participants. Completed in 23 April 2023.

Timeline

10 January 2022

Primary endpoint
23 April 2023

23 April 2023

Quick facts

Lead sponsor	University of Vienna
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	none
Primary purpose	basic science
Enrollment	65
Start date	10 January 2022
Primary completion	23 April 2023
Estimated completion	23 April 2023
Sites	1 location across Austria

Drugs / interventions tested

• Training intervention
• High Glycaemic Index
• LCHF
• Low Glycaemic Index

Conditions studied

• Substrate Metabolism During Exercise — all drugs for Substrate Metabolism During Exercise →

Sponsor

University of Vienna

Who can join

Adults 18 to 40, male only, with Substrate Metabolism During Exercise. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

Substrate metabolism during exercise can be influenced by various nutritional regimes. The effectiveness of the different nutritional regimes, which differ in their carbohydrate content, will be investigated not only by functional tests but also the measurement of the mechanistic processes in the muscle will be explored.

Magnetic resonance (MR), better known as magnetic resonance imaging (MRI), has been widely used in clinical practice as a non-invasive imaging technique. Importantly, in addition to producing anatomical images, an MR scanner also offers the possibility to measure the concentrations of a number of metabolic products. This is done through a technique known as magnetic resonance spectroscopy (MRS).

This research project asks the following questions:

* Can a diet containing carbohydrates with a low glycemic index achieve the same adaptations in basic endurance/fat metabolism as a high fat, low carbohydrate (ketogenic) diet?
* Does a high-fat, low-carbohydrate diet, compared with a high-carbohydrate diet, prevent improvements in performance in the submaximal and maximal range?
* What is the effect of diets with different carbohydrate content and variable glycemic index on endurance performance in a half marathon and a time trial?
* How do the diets with different carbohydrate content and variable glycaemic index affect the energy and glycogen stores in the muscles?

In active recreational athletes, the objectives are: (1) to investigate the effects of different diets with variable carbohydrate content and glycaemic index on substrate metabolism, (2) to determine the effects of the different diets on energy stores using multinuclear dynamic magnetic resonance spectroscopy, and (3) to measure the effects of the different diets on endurance performance.

Publications & conference data

3 peer-reviewed publications reference this trial (live from Europe PMC):

1. A low-carbohydrate, high-fat diet leads to unfavorable changes in blood lipid profiles compared to carbohydrate-rich diets with different glycemic indices in recreationally active men.
   Kripp AM, Feichter A, König D. · · 2024 · cited 8× · PMID 39483781 · DOI 10.3389/fnut.2024.1473747
2. Effects of a 10-Week Exercise and Nutritional Intervention with Variable Dietary Carbohydrates and Glycaemic Indices on Substrate Metabolism, Glycogen Storage, and Endurance Performance in Men: A Randomized Controlled Trial.
   Moitzi AM, Krššák M, Klepochova R, Triska C, et al · · 2024 · cited 4× · PMID 38600291 · DOI 10.1186/s40798-024-00705-9
3. Exploring the non-targeted metabolomic landscape in endurance-trained runners following 10 weeks of different dietary patterns and concomitant training.
   Kripp AM, Tahir A, Draxler A, Speiser M, et al · · 2025 · PMID 40697094 · DOI 10.1080/15502783.2025.2536139