Dietary Macronutrient Manipulation and Substrate Oxidation During Exercise

University of Birmingham13 enrolled

Overview

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.

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 Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Dietary Manipulation

Interventions

Diet with a different macronutrient content AOTHER

A diet with altered macronutrient content will be provided to participants on days 4-6 of experimental arm 1.

Diet with a different macronutrient content BOTHER

A diet with a different macronutrient content compared to arm 1 will be provided to participants on days 4-6 of experimental arm 2.

Diet with a different macronutrient content COTHER

A diet with a different macronutrient content compared to arms 1 and 2 will be provided to participants on days 4-6 of experimental arm 3.

Eligibility

Sex: MALEMin age: 18 YearsMax age: 45 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

School of Sport Exercise and Rehabilitation Sciences, University of Birmingham

Birmingham, United Kingdom

Outcomes

Primary Outcomes

Muscle glycogen concentration after dietary macronutrient manipulation

Muscle glycogen concentration will be measured after the dietary macronutrient manipulation intervention.

Time frame: Day 7 of all experimental arms

Secondary Outcomes

Rate of fat oxidation at rest (g/min)

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).

Time frame: For 20 min on Day 7 of all experimental arms

Rate of fat oxidation during exercise (g/min)

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).

Time frame: During 60 min of exercise on day 7 of all experimental arms

Rate of carbohydrate oxidation at rest (g/min)

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).

Time frame: For 20 min on Day 7 of all experimental arms

Rate of carbohydrate oxidation during exercise (g/min)

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).

Time frame: During 60 min of exercise on day 7 of all experimental arms

Blood glucose concentration

Blood glucose concentration will be assessed in blood samples taken during exercise.

Data from ClinicalTrials.gov

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