Maximal Fat Oxidation and Fuel Use During Exercise

NCT04678713 | Completed

• 1 other identifier: Variation in MFO
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Fat and carbohydrate are the two main energy stores available as fuel during exercise. It is well known that the exercise intensity and feeding status are the major factors determining the type of fuel used during exercise. During prolonged exercise at low to moderate exercise fat is the primary fuel being used and to improve performance studies has tried to understand strategies to maximize muscle glycogen storage and elevate fat oxidation during exercise. With this strategy they aim for preserving the limited muscle glycogen stores and thus improving endurance performance. In relation to this the maximal fat oxidation (MFO: The highest rate of fat oxidation across all exercise intensities) has been studied as increasing the fat oxidation could decrease the depletion of the glycogen stores. Further it has recently been shown that MFO is related to performance in endurance trained. However the MFO has been found to vary markedly between trained individuals matched on their activity level. It has been suggested that the diet and subsequent substrate availability during exercise contributes independently to the variation in MFO. However, the measurements have never been evaluated in a trained group with similar aerobic capacity and training status. Therefore, the aim of the study is to investigate the effect of a short term fat rich or carbohydrate rich diet on MFO in well trained men with a high vs. a low MFO. The hypothesis is that 3 days of a fat-rich diet will increase MFO while 3 days of a Carbohydrate rich diet will decrease MFO in both individuals with a high MFO (HiMFO) and a low MFO (LoMFO). Furthermore, it is hypothesized that HiMFO will have a significantly higher MFO after both diets compared to LoMFO. Lifestyle and physiological factors have been investigated to determine the variation of the MFO capacity. However, these factors can only explain 50% of the interindividual variability in MFO. Despite the critical role of fat oxidation during exercise, few studies have explored the differences in skeletal muscle characteristics between HiMFO and LoMFO. The second aim of the study is thereby to investigate if muscle characteristics can explain the variability in MFO within well-trained males. The hypothesis is that HiMFO will have more favorable muscle characteristics for fat oxidation compared to LoMFO including a higher oxidative capacity, intramuscular triacylglycerol concentration and a higher expression of key enzymes in lipid metabolism.

Conditions

Obesity

Keywords

Maximal fat oxidation; Ketogenic diet; Carbohydrate rich diet; Fat rich diet; Maximal aerobic capacity; Trained individuals; Adipose triglyceride lipase; The maximal fat oxidation intensity; Glucose Transporter 4; Citrate synthase; Hydroxyacyl-Coenzyme A dehydrogenase; Hormone sensitive lipase; Intramuscular Triacylglycerol; Respiratory exchanges ratio; Glycogen synthase; Hexokinase II

Outcome Measures

Primary Outcomes (1)

• Change in maximal fat oxidation

  Change in maximal fat oxidation (gram/min.) from baseline to after 3-day carbohydrate rich or fat rich diet in moderately trained males

  Baseline and after three days diet

Secondary Outcomes (1)

• Change in muscle triacylglycerol

  Baseline and after three days diet

Study Arms (2)

Fat rich diet

EXPERIMENTAL

Participants consuming 3 days of fat rich diet

Dietary Supplement: investigate the nutritional determinants of MFO in moderate to well-train individuals; Other: Investigate the physiological determinants of MFO in moderate to well-train individuals

Carbohydrate rich diet

EXPERIMENTAL

Participants consuming 3 days of carbohydrate rich diet

Dietary Supplement: investigate the nutritional determinants of MFO in moderate to well-train individuals; Other: Investigate the physiological determinants of MFO in moderate to well-train individuals

Interventions

investigate the nutritional determinants of MFO in moderate to well-train individuals DIETARY_SUPPLEMENT

The participants will receive a 3-day fat rich or a carbohydrate rich diet. The participants will perform a maximal fat oxidation test before and after the diet intervention to evaluate the effect of the two diets on MFO.

Carbohydrate rich diet; Fat rich diet

Investigate the physiological determinants of MFO in moderate to well-train individuals OTHER

Muscle biopsies will be obtained at baseline to compare muscle characteristics between well-matched train individuals with a high compared to a low maximal fat oxidation.

Carbohydrate rich diet; Fat rich diet

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age: 18 to 40 years
• Physical activity \> 3 times/week
• Maximal aerobic capacity \> 50 mlO2/min/kg
• BMI \< 30 kg/m2

You may not qualify if:

• Aged below 18 years or above 40 years
• Maximal aerobic capacity \< 50 mlO2/kg/min
• Body mass index \> 30 kg/m2
• Taking any prescription medication influencing metabolism
• Having existing cardiovascular, metabolic or musculoskeletal conditions that may influence ability to exercise or study outcomes

Sponsors & Collaborators

• University of Copenhagen: lead
• Deakin University: collaborator

Study Sites (1)

Xlab, Faculty of Health and Medical Sciences, University of Copenhagen

Copenhagen, 2200, Denmark

Location

MeSH Terms

Conditions

Obesity; Wolman Disease

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Cholesterol Ester Storage Disease; Lipidoses; Lipid Metabolism, Inborn Errors; Metabolism, Inborn Errors; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Lysosomal Storage Diseases; Infant, Newborn, Diseases; Lipid Metabolism Disorders; Metabolic Diseases

Study Officials

• Jørn Helge, Professor

  Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: As the participants receive a specific diet, and have to buy their gloceries themself, it is not possible to mask what kind of diet they consume. They will be randomised into what kind of diet they receive.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: The participants will be separated into 2 groups by stratified randomization consuming either a Fat rich diet (HiFAT) or a carbohydrate rich diet (HiCHO) (n=40 in total). When all 40 participants have completed the study, the results will be analysed by separating the two groups into two subgroups based on the median of the MFO

Study Record Dates

• First Submitted: November 13, 2020
• First Posted: December 22, 2020
• Study Start: January 1, 2020
• Primary Completion: September 1, 2021
• Study Completion: September 30, 2021
• Last Updated: February 15, 2024

Record last verified: 2024-02

Data Sharing

• IPD Sharing: Will not share

Locations

DK (1)