Clinical trial NCT02605291: Dietary Macronutrient Manipulation and Substrate Oxidation During Exercise
Official title: The Effect of Dietary Macronutrient Manipulation and Glycogen Depleting Exercise on Substrate Oxidation at Rest and During Exercise
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Dietary Manipulation
Lead sponsor: University of Birmingham
Sponsor class: OTHER
Collaborators: name: Lucozade Ribena Suntory
First posted: 2015-11-16
Enrollment: 13
Sex: MALE
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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)

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

Primary outcomes:
measure: Muscle glycogen concentration after dietary macronutrient manipulation
timeFrame: Day 7 of all experimental arms
Secondary outcomes:
measure: Rate of fat oxidation at rest (g/min)
timeFrame: For 20 min on Day 7 of all experimental arms
measure: Rate of fat oxidation during exercise (g/min)
timeFrame: During 60 min of exercise on day 7 of all experimental arms
measure: Rate of carbohydrate oxidation at rest (g/min)
timeFrame: For 20 min on Day 7 of all experimental arms
measure: Rate of carbohydrate oxidation during exercise (g/min)
timeFrame: During 60 min of exercise on day 7 of all experimental arms
measure: Blood glucose concentration
timeFrame: At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms.
measure: Blood insulin concentration
timeFrame: At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms
measure: Blood fatty acid concentration
timeFrame: At 0, 20, 40 and 60min into exercise on day 7 of all experimental arms
measure: Change in intramuscular triglyceride (IMTG) content after exercise
timeFrame: IMTG content measured just before and immediately after 60min of exercise on Day 7 of all experimental arms
Other outcomes:
Locations:
city: Birmingham
country: United Kingdom
facility: School of Sport Exercise and Rehabilitation Sciences, University of Birmingham
Study officials:
affiliation: University of Birmingham
name: Gareth A Wallis, PhD
role: PRINCIPAL_INVESTIGATOR
References: