Exercise Substrate Utilisation and Endurance Performance Following Short-term Manipulation of Dietary Fat Intake

Exercise Substrate Utilisation and Endurance Performance Following Short-term Manipulation of Dietary Fat Intake in Women

The capacity to burn fat as fuel for exercise may have important implications for sporting performance, with dietary fat intake positively influencing this ability.

Endurance performance and the ability to burn fat will be measured in women runners following the consumption of 3 diets varying in the amount of fat and carbohydrate.

Study Overview

• Status: Unknown
• Conditions: Dietary Modification
• Intervention / Treatment: Dietary supplement: High Fat; Dietary supplement: Normal; Dietary supplement: Normal + Extra Fat

Detailed Description

Dietary fat intake positively influences the ability to burn fat during exercise in women but not men, whereas carbohydrate intake negatively influences fat oxidation in both sexes. The independent nature of dietary fat intake as a predictor of the ability to burn fat in women suggests that in conditions of adequate carbohydrate intake providing additional fat may increase fat oxidation in women whereas it does not in men. It is of interest to explore if indeed women are responsive (i.e., increase in fat oxidation) to short-term increases in dietary fat intake induced by overfeeding (adequate carbohydrate) or if as appears to be the case in men reduced carbohydrate intake as typically employed in high-fat, low carbohydrate dietary studies is also a prerequisite for enhancing fat oxidation in women, and whether this translates into a difference in exercise endurance performance.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • West Midlands
    • Birmingham, West Midlands, United Kingdom, B15 2TT
      • University of Birmingham

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• BMI >17.0 < 25 kg/m2
• Good General Health
• Accustomed to vigorous physical activity
• Run > 2 times per week
• V̇O2max >50ml/kg/min
• Weight Stable > last 6months
• Non Smoker
• Pre-menopausal, and either eumenorrheic and regularly menstruating, or using monophasic hormonal oral contraceptives for > 3 months.

Exclusion Criteria:

• Currently taking part in another scientific/clinical study
• Taking any prescription drug / supplement thought to influence metabolism
• Following unusual dietary practices (such as intermittent fasting or low carbohydrate diets)
• Pregnant
• Breast Feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High Fat; High Fat - Carbohydrate (20%), Fat (65%), Protein (15%)	Dietary supplement: High Fat; High Fat - Carbohydrate (20%), Fat (65%), Protein (15%)
Experimental: Normal; Normal - Carbohydrate (50%), Fat (35%) and Protein (15%)	Dietary supplement: Normal; Normal - Carbohydrate (50%), Fat (35%) and Protein (15%)
Experimental: Normal + Extra Fat; Normal + Extra Fat - Carbohydrate (50%), Fat (65%), Protein (15%). Carbohydrate and protein intake identical in absolute amounts to NORM (Normal), with an additional 30% extra energy coming from fat.	Dietary supplement: Normal + Extra Fat; Normal + Extra Fat - Carbohydrate (50%), Fat (65%), Protein (15%). Carbohydrate and protein intake identical in absolute amounts to NORMAL, with an additional 30% extra energy coming from fat.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rates of fat oxidation during exercise	Rates of fat oxidation to be measured via indirect calorimetry during 90 minutes of submaximal exercise	90 minutes of sub-maximal exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
5km running performance	Time to complete 5km on a treadmill	Immediately following measurement of Primary Outcome measure
Change in plasma glucose concentration	Area under the plasma concentration versus time curve (AUC) of glucose	90 minutes sub-maximal exercise
Change in Free Fatty Acid concentration	Area under the plasma concentration versus time curve (AUC) of Free Fatty Acid	90 minutes sub-maximal exercise
Change in plasma glycerol concentration	Area under the plasma concentration versus time curve (AUC) of glycerol	90 minutes sub-maximal exercise

Collaborators and Investigators

• Sponsor: University of Birmingham
• Collaborators: GlaxoSmithKline
• Investigators: Principal Investigator: Gareth A Wallis, PhD, University of Birmingham

Study record dates

Study Major Dates

• Study Start: March 1, 2015
• Primary Completion (Anticipated): June 1, 2016
• Study Completion (Anticipated): June 1, 2016

Study Registration Dates

• First Submitted: May 13, 2015
• First Submitted That Met QC Criteria: October 2, 2015
• First Posted (Estimate): October 6, 2015

Study Record Updates

• Last Update Posted (Estimate): May 13, 2016
• Last Update Submitted That Met QC Criteria: May 11, 2016
• Last Verified: May 1, 2016

More Information

Terms related to this study

• Other Study ID Numbers: ERN_15-0012

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO