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Completed

NCT Number: NCT02605291

Dietary Macronutrient Manipulation and Substrate Oxidation During Exercise

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.

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Key information

Conditions

Dietary Manipulation

Age range

18 year–45 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

School of Sport Exercise and Rehabilitation Sciences, University of Birmingham

Birmingham, B15 2TT, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Diet with a different macronutrient content A

Other

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 B

Other

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 C

Other

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.

Interval treadmill running exercise

Other

Participants will perform interval treadmill running exercise on days 4 and 5 of all experimental arms.

Steady state treadmill running exercise

Other

Participants will perform steady state treadmill running exercise on day 7 of all experimental arms.

Primary outcomes

  1. Muscle glycogen concentration after dietary macronutrient manipulation

    Time frame: Day 7 of all experimental arms

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

Secondary outcomes

  1. Rate of fat oxidation at rest (g/min)

    Time frame: 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).

  2. Rate of fat oxidation during exercise (g/min)

    Time frame: 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).

  3. Rate of carbohydrate oxidation at rest (g/min)

    Time frame: 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).

  4. Rate of carbohydrate oxidation during exercise (g/min)

    Time frame: 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).

  5. Blood glucose concentration

    Time frame: 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.

  6. Blood insulin concentration

    Time frame: 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.

  7. Blood fatty acid concentration

    Time frame: 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.

  8. Change in intramuscular triglyceride (IMTG) content after exercise

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

University of Birmingham

Other

Collaborators

  • Lucozade Ribena Suntory

Registry information

Official study title

The Effect of Dietary Macronutrient Manipulation and Glycogen Depleting Exercise on Substrate Oxidation at Rest and During Exercise

Important dates

Study start
2016
Primary completion
2017
Study completion
2017
First posted
Nov 16, 2015
Registry last updated
Oct 11, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.