Dietary Macronutrient Manipulation and Substrate Oxidation During Exercise

Not Applicable

Completed

• Conditions: Dietary Manipulation
• Interventions: Other: Diet with a different macronutrient content C; Other: Diet with a different macronutrient content A; Other: Diet with a different macronutrient content B; Other: Interval treadmill running exercise; Other: Steady state treadmill running exercise

• Registration Number: NCT02605291
• Lead Sponsor: University of Birmingham

Brief Summary

This study will investigate the effect of dietary macronutrient manipulation on glycogen (stored carbohydrate) levels in the muscle and substrate oxidation during exercise. The investigators will investigate the hypothesis that manipulating the macronutrient content of the diet will alter the levels of glycogen in the muscle and, in turn, substrate oxidation during exercise.

Detailed Description

One way to help reduce body fat is to expend more energy from the oxidation of fat as a fuel. Exercise is one way to increase fat oxidation. The extent to which exercise facilitates the use of fat as a fuel may be influenced by an individual's dietary intake.

This study aims to establish the effect of dietary macronutrient manipulation on muscle glycogen levels and substrate oxidation during exercise. Participants will undertake three separate trial periods. During each trial period participants will consume a diet containing different macronutrient compositions. For each of the trials the investigators will assess how the macronutrient composition of the diet affects muscle glycogen level and substrate oxidation during exercise.

Study Timeline

• Study First Submitted: 2015-11-06
• Study First Submitted QC: 2015-11-11
• Study First Posted: 2015-11-16
• Study Start: 2016-01
• Primary Completion: 2017-06
• Study Completion: 2017-06
• Status Verified: 2018-10
• Last Update Submitted: 2018-10-10
• Last Update Posted: 2018-10-11

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 13

Inclusion Criteria

• Good general health
• Non-smoking - currently and for the past 5 years
• Fitness - V̇O2max 40-60 ml/kg/min
• Body mass index (20-25 kg/m2)

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Exclusion Criteria

• Known or suspected intolerance to the dietary interventions or their stated ingredients.
• Participation in another clinical study or receipt of an investigational drug within 30 days of the screening visit.
• Previous participation in this study.
• Recent history (within the last year) of alcohol or other substance abuse.
• An employee of the sponsor or the study site or members of their immediate family.
• Abnormal / extreme habitual dietary practice / intake
• Recent (≤3 months) dietary practice that may be deemed as low and/or high in macronutrients will be excluded.
• The taking of any prescribed medication

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Experimental arm 2	Steady state treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 3	Diet with a different macronutrient content C	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 3	Steady state treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 1	Diet with a different macronutrient content A	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 2	Diet with a different macronutrient content B	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 3	Interval treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 1	Interval treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 1	Steady state treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.
Experimental arm 2	Interval treadmill running exercise	One of three 7-day study arms consisting of 3 days of standardised diet followed by 3 days of dietary macronutrient manipulation and 1 day of experimental testing.

Primary Outcome Measures

Name	Time	Method
Muscle glycogen concentration after dietary macronutrient manipulation	Day 7 of all experimental arms	Muscle glycogen concentration will be measured after the dietary macronutrient manipulation intervention.

Secondary Outcome Measures

Name	Time	Method
Rate of fat oxidation during exercise (g/min)	During 60 min of exercise on day 7 of all experimental arms	Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) during exercise will be measured using indirect calorimetry to calculate the rate of fat oxidation during exercise (g/min).
Rate of carbohydrate oxidation at rest (g/min)	For 20 min on Day 7 of all experimental arms	Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) at rest will be measured using indirect calorimetry to calculate the rate of carbohydrate oxidation at rest (g/min).
Rate of carbohydrate oxidation during exercise (g/min)	During 60 min of exercise on day 7 of all experimental arms	Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) during exercise will be measured using indirect calorimetry to calculate the rate of carbohydrate oxidation during exercise (g/min).
Blood insulin concentration	At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms	Blood insulin concentration will be assessed in blood samples taken during exercise.
Rate of fat oxidation at rest (g/min)	For 20 min on Day 7 of all experimental arms	Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) at rest will be measured using indirect calorimetry to calculate the rate of fat oxidation at rest (g/min).
Blood glucose concentration	At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms.	Blood glucose concentration will be assessed in blood samples taken during exercise.
Blood fatty acid concentration	At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms	Blood fatty acid concentration will be assessed in blood samples taken during exercise.
Change in intramuscular triglyceride (IMTG) content after exercise	IMTG content measured just before and immediately after 60min of exercise on Day 7 of all experimental arms	IMTG utilisation during exercise (or change in IMTG content pre-post exercise) will be measured by comparing the IMTG content before and after exercise.

Trial Locations

Locations (1)

School of Sport Exercise and Rehabilitation Sciences, University of Birmingham; 🇬🇧 Birmingham, United Kingdom