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Completed

NCT Number: NCT02744183

Training in the Fasted State, Glucose Metabolism and Energy Balance

In healthy individuals, the body responds to glucose (sugar) ingestion by reducing the amount released from the liver. At the same time, skeletal muscles increase the rate at which they remove the glucose from the bloodstream, via the actions of the hormone insulin. This ensures that blood glucose levels remain in a controlled range. However, in developed countries, diseases such as metabolic syndrome and type 2 diabetes are becoming prevalent, due to dietary modifications and a reduction in physical activity. As one of the prominent barriers to regular physical activity is a lack of time, finding ways to maximize the health benefits of exercise is a priority for researchers.

The investigators want to understand potential differences in the effects of six weeks of aerobic training, with the exercise performed either after breakfast or after a prolonged fast. Specifically, this research aims to investigate whether there is a difference in the change in processes implicated in glucose regulation and secondly, in subsequent eating and physical activity behaviors. By investigating these changes this work will explore how exercise and nutrition can be optimized to benefit health and weight loss.

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Key information

Conditions

Glucose Metabolism Disorders Behavior Metabolic Diseases Motor Activity Nutritional and Metabolic Diseases

Age range

18 year–49 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Department for Health, University of Bath

Bath, BA2 7AY, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Male
  • Aged 18-49
  • Body mass index (BMI) > 25 kg/m2
  • Weight stable for > 6 months
  • Not currently engaging in any form of structured exercise
  • Be able and willing to give informed oral and written consent
  • Complete and meet the defined criteria of pre-study questionnaires and screen

Exclusion criteria

  • Have a history of metabolic, cardio-pulmonary or musculoskeletal disease
  • Have plans to change diet and/or physical activity outside of the intervention
  • Taking regular medication or food supplements from which it is not possible to refrain and which are known to influence any of the outcome measures.
  • Failure to refrain from alcohol and/or caffeine containing drinks or strenuous exercise one day before or during the trial days
  • Smokers
  • Any reported condition or behavior deemed to pose a risk to the participant or introduce bias into the experiment

Treatment and study plan

Exercise

Behavioral

Moderate intensity exercise

Breakfast

Behavioral

Breakfast consumption

Maintain habitual habits

Behavioral

Normal physical activity and dietary behaviors maintained

Primary outcomes

  1. Postprandial plasma glucose concentrations

    Time frame: 120 mins - (change after 6 weeks)

    Response to oral glucose tolerance test (area under the curve)

  2. Postprandial insulin concentrations

    Time frame: 120 mins - (change after 6 weeks)

    Response to oral glucose tolerance test (area under the curve)

Secondary outcomes

  1. Oral Glucose Insulin Sensitivity Index

    Time frame: 120 mins - (change after 6 weeks)

    Response to oral glucose tolerance test

  2. Cardiorespiratory fitness (VO2max)

    Time frame: Change after 6 weeks

  3. Habitual energy intake

    Time frame: Change after 6 weeks

    Assessed via a food diary, completed at baseline and during the last week of the intervention

  4. Habitual energy expenditure

    Time frame: Change after 6 weeks

    Assessed via an Actiheart monitor, completed at baseline and during the last week of the intervention

  5. Body mass (kg)

    Time frame: Change after 6 weeks

  6. Waist and hip circumference (cm)

    Time frame: Change after 6 weeks

  7. Maximal rate of whole-body lipid oxidation (g/min)

    Time frame: Change after 6 weeks

    During an incremental exercise test

  8. Fasting plasma glucose concentration

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma glucose concentration (mmol/L)

  9. Fasting plasma insulin concentration

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma insulin concentration (pmol/L)

  10. Postprandial non-esterified fatty acid concentrations

    Time frame: 120 mins - (change after 6 weeks)

    Response to oral glucose tolerance test (total and incremental area under the curve)

  11. Fasting plasma triglyceride concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma triglyceride concentrations (mmol/L)

  12. Fasting plasma total cholesterol concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma total cholesterol concentrations (mmol/L)

  13. Fasting plasma HDL cholesterol concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma HDL cholesterol concentrations (mmol/L)

  14. Fasting plasma LDL cholesterol concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma LDL cholesterol concentrations (mmol/L)

  15. Fasting plasma non-esterified fatty acid concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma non-esterified fatty acid concentrations (mmol/L)

  16. Waist to hip ratio

    Time frame: Change after 6 weeks

    Waist circumference (cm) divided by hip circumference (cm)

  17. Citrate Synthase Activity (mitochondrial citrate synthase activity in each muscle sample in an immunocapture based manner)

    Time frame: Change after 6 weeks

    Skeletal muscle (vastus lateralis). Citrate Synthase Activity Assay Kit.

  18. Protein content of mitochondrial respiratory chain proteins

    Time frame: Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units).

    Skeletal muscle (vastus lateralis). Complex I, Complex II, Complex III, Complex IV.

  19. Protein content of carnitine palmitoyltransferase I (CPT-1)

    Time frame: Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units)

    Skeletal muscle (vastus lateralis)

  20. Protein content of cluster of differentiation 36 (CD36)

    Time frame: Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units)

    Skeletal muscle (vastus lateralis)

  21. Protein content (total and phosphorylated form) of AMP-activated protein kinase (AMPK)

    Time frame: Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units)

    Skeletal muscle (vastus lateralis)

  22. Resting metabolic rate (RMR)

    Time frame: Change after 6 weeks

    Assessed via indirect calirometry

  23. Energy balance

    Time frame: Change after 6 weeks (during week 6 of intervention versus baseline monitoring)

    Total energy expenditure minus total energy intake

  24. Whole-body lipid utilisation during exercise

    Time frame: Change throughout complete training period (weeks 1 through to 6). Samples will be collected during every training session (three times weekly for six weeks)

    Assessed via indirect calirometry during every exercise session (at ten minute intervals)

  25. Whole-body carbohydrate utilisation during exercise

    Time frame: Change throughout complete training period (weeks 1 through to 6). Samples will be collected during every training session (three times weekly for six weeks)

    Assessed via indirect calirometry during every exercise session (at ten minute intervals)

  26. Homeostasis Model Assessment (HOMA2-IR)

    Time frame: Change after 6 weeks

    The Homeostasis Model Assessment (HOMA) estimate of steady state beta cell function (%B) and insulin sensitivity (%S). Derived from fasting plasma glucose and fasting plasma insulin concentrations.

  27. Fasting plasma glycerol concentrations

    Time frame: Basal Concentrations - (change after 6 weeks)

    Fasting plasma glycerol concentrations (mmol/L)

  28. Postprandial plasma glycerol concentrations

    Time frame: Change after 6 weeks

    Response to oral glucose tolerance test (total and incremental area under the curve)

  29. Adipose Tissue Insulin Resistance Index (Adipo-IR)

    Time frame: Change after 6 weeks

    Response to oral glucose tolerance test (total and incremental area under the curve)

Sponsors and collaborators

Lead sponsor

University of Bath

Other

Registry information

Important dates

Study start
2016
Primary completion
2018
Study completion
2019
First posted
Apr 20, 2016
Registry last updated
Nov 25, 2022

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.

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