Training in the Fasted State, Glucose Metabolism and Energy Balance

Not Applicable

Completed

• Conditions: Glucose Metabolism Disorders
• Interventions: Behavioral: Exercise; Behavioral: Maintain habitual habits; Behavioral: Breakfast

• Registration Number: NCT02744183
• Lead Sponsor: University of Bath

Brief Summary

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.

Detailed Description

Not available

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study First Submitted: 2016-04-11
• Study First Submitted QC: 2016-04-15
• Study First Posted: 2016-04-20
• Study Start: 2016-10
• Primary Completion: 2018-08
• Study Completion: 2019-09
• Status Verified: 2022-11
• Last Update Submitted: 2022-11-23
• Last Update Posted: 2022-11-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 30

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

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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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Fasted Exercise	Exercise	6 weeks of moderate intensity exercise with breakfast omission
Fed Exercise	Breakfast	6 weeks of moderate intensity exercise with breakfast consumption
Control Group	Maintain habitual habits	Maintain habitual habits
Fed Exercise	Exercise	6 weeks of moderate intensity exercise with breakfast consumption

Primary Outcome Measures

Name	Time	Method
Postprandial plasma glucose concentrations	120 mins - (change after 6 weeks)	Response to oral glucose tolerance test (area under the curve)
Postprandial insulin concentrations	120 mins - (change after 6 weeks)	Response to oral glucose tolerance test (area under the curve)

Secondary Outcome Measures

Name	Time	Method
Oral Glucose Insulin Sensitivity Index	120 mins - (change after 6 weeks)	Response to oral glucose tolerance test
Habitual energy expenditure	Change after 6 weeks	Assessed via an Actiheart monitor, completed at baseline and during the last week of the intervention
Waist and hip circumference (cm)	Change after 6 weeks
Cardiorespiratory fitness (VO2max)	Change after 6 weeks
Habitual energy intake	Change after 6 weeks	Assessed via a food diary, completed at baseline and during the last week of the intervention
Body mass (kg)	Change after 6 weeks
Fasting plasma glucose concentration	Basal Concentrations - (change after 6 weeks)	Fasting plasma glucose concentration (mmol/L)
Maximal rate of whole-body lipid oxidation (g/min)	Change after 6 weeks	During an incremental exercise test
Fasting plasma HDL cholesterol concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma HDL cholesterol concentrations (mmol/L)
Fasting plasma LDL cholesterol concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma LDL cholesterol concentrations (mmol/L)
Postprandial plasma glycerol concentrations	Change after 6 weeks	Response to oral glucose tolerance test (total and incremental area under the curve)
Fasting plasma insulin concentration	Basal Concentrations - (change after 6 weeks)	Fasting plasma insulin concentration (pmol/L)
Postprandial non-esterified fatty acid concentrations	120 mins - (change after 6 weeks)	Response to oral glucose tolerance test (total and incremental area under the curve)
Citrate Synthase Activity (mitochondrial citrate synthase activity in each muscle sample in an immunocapture based manner)	Change after 6 weeks	Skeletal muscle (vastus lateralis). Citrate Synthase Activity Assay Kit.
Fasting plasma triglyceride concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma triglyceride concentrations (mmol/L)
Fasting plasma total cholesterol concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma total cholesterol concentrations (mmol/L)
Fasting plasma non-esterified fatty acid concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma non-esterified fatty acid concentrations (mmol/L)
Waist to hip ratio	Change after 6 weeks	Waist circumference (cm) divided by hip circumference (cm)
Protein content of mitochondrial respiratory chain proteins	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.
Resting metabolic rate (RMR)	Change after 6 weeks	Assessed via indirect calirometry
Adipose Tissue Insulin Resistance Index (Adipo-IR)	Change after 6 weeks	Response to oral glucose tolerance test (total and incremental area under the curve)
Protein content of carnitine palmitoyltransferase I (CPT-1)	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)
Protein content of cluster of differentiation 36 (CD36)	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)
Protein content (total and phosphorylated form) of AMP-activated protein kinase (AMPK)	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)
Whole-body carbohydrate utilisation during exercise	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)
Homeostasis Model Assessment (HOMA2-IR)	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.
Energy balance	Change after 6 weeks (during week 6 of intervention versus baseline monitoring)	Total energy expenditure minus total energy intake
Whole-body lipid utilisation during exercise	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)
Fasting plasma glycerol concentrations	Basal Concentrations - (change after 6 weeks)	Fasting plasma glycerol concentrations (mmol/L)

Trial Locations

Locations (1)

Department for Health, University of Bath; 🇬🇧 Bath, United Kingdom