Carbohydrate MetabolismNCT07476989
Effects of Dual-Source Carbohydrate Intake and Liver Glycogen Repletion After Overnight Fasting.
A study testing No breakfast, Breakfast (0% Fructose) and Breakfast (50% fructose) in people with Carbohydrate Metabolism and Hepatic Glycogen Storage, run by Manchester Metropolitan University.
Trial summary
This study is looking at whether eating a breakfast which has two different sources of carbohydrates, glucose and fructose (found in foods like honey and fruits), can increase how much glycogen can be stored in the liver. Glucose is a type of sugar that the body uses to provide energy during exercise. Read more about this study
- Who is it for?
- Ages 18 to 45 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Carbohydrate Metabolism, Hepatic Glycogen Storage, Healthy Adult Male
- What is being tested?
- No breakfast, Breakfast (0% Fructose) and Breakfast (50% fructose)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- No sites listed yet
- Study dates
- Mar 2026to Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- A male (at birth) aged between 18 and 45.
- Regularly training for a specific sport (must include cycling) at least 3 times per week (with the purpose of competing).
- VO2 peak >50 (ml.kg.min)
- A current non-smoker/vaper (must not have smoked or vaped within the last 6 months)
- Do not have any medical conditions or are taking any medications or supplements which can affect the study's outcome measures.
- Free from any metallic implants, including permanent jewellery (that can't be removed)
- No known intolerances or allergies to any component of the nutritional supplement
Who cannot join
- Are not a male (at birth) aged between 18 and 45.
- Do not regularly train for a specific sport (must include cycling) at least 3 times per week (with the purpose of competing).
- Does not have a VO2 max/peak >50 (ml.kg.min)
- A current smoker/vaper (must not have smoked or vaped within the last 6 months)
- Have any medical conditions or are taking any medications or supplements which can affect the study's outcome measures
- Have any metallic implants, including permanent jewellery (that can't be removed)
- Known intolerances or allergies to any component of the nutritional supplement.
About this study
Official title: The Effects of a Dual-Source High-Carbohydrate Breakfast on Hepatic Glycogen Storage Following an Overnight Fast.
This study is looking at whether eating a breakfast which has two different sources of carbohydrates, glucose and fructose (found in foods like honey and fruits), can increase how much glycogen can be stored in the liver. Glucose is a type of sugar that the body uses to provide energy during exercise. When it is not circulating in the blood, it is stored in the muscles and liver. The stored version of glucose is often referred to as glycogen. When the body needs energy, for example, it will break down glycogen into glucose so that it can be used as fuel.
Muscle and liver glycogen stores are vital in providing energy during prolonged exercise, and strenuous activity can rapidly deplete these stores, leading to increased fatigue and a decline in performance. Liver glycogen, however, is particularly important because it controls blood glucose levels. This is important because the brain and other organs are constantly relying on the supply of glucose to function properly.
Read more
When sleeping, the body goes through a natural period of fasting. During this period, the liver gradually breaks down its glycogen stores to release glucose into the bloodstream. Because of this, following sleep, liver glycogen stores are automatically low (which is why having breakfast is important). There is research to suggest that eating a high-carbohydrate breakfast can prevent further declines in liver glycogen; however, it is not known if eating different types of carbohydrates within the breakfast (glucose and fructose together) will affect the liver's ability to store glycogen. This research will aid in understanding optimal ways to increase liver glycogen stores before performing exercise, which may influence exercise performance.
Therefore, the main aim of this study is:
- Investigate whether a high fructose breakfast will increase liver glycogen storage
To achieve this, participants will be recruited to complete a randomised crossover study where they will undertake three different conditions. All laboratory trials will take place at the Manchester Metropolitan University Institute of Sport.
- No breakfast (Control)
- 3 g/kg of body mass of carbohydrate (of which contains 0% fructose)
- 3 g/kg of body mass of carbohydrate (of which contains50% fructose)
Liver glycogen stores will be measured using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). The investigators will measure liver glycogen content, liver volume, and stomach volume. Blood samples will also be taken to measure different metabolic hormone responses.
Read the detailed description
Glycogen stores in the muscle and liver play a crucial role in providing fuel during prolonged exercise and strenuous activities, which can rapidly deplete these stores, leading to increased fatigue and reduced performance. During prolonged exercise, liver glycogen is broken down to maintain blood glucose (sugar) levels and provide an important fuel source for the exercising muscles. Accordingly, liver glycogen is important for our ability to perform prolonged endurance exercise.
Following sleep, the body is placed under a natural period of fasting; because of this, the body's main source of fuel derives from liver glycogen stores, meaning hepatic glycogen stores decline sufficiently during this period. Accordingly, without sufficient pre-exercise carbohydrate intake, athletes begin training or competition with reduced liver glycogen availability, which can impair their ability to maintain blood glucose during prolonged exercise and may result in hypoglycaemia and subsequent fatigue. Whilst current guidelines suggest that pre-exercise carbohydrate intake may support the replenishment of depleted liver glycogen stores, it is currently unclear whether the composition of carbohydrates contained within the breakfast meal may impact the ability of the liver to store glycogen.
Fructose is primarily metabolised in the liver and enters hepatic carbohydrate metabolism downstream to key regulatory steps in glycolysis. Research has shown that fructose preferentially contributes to hepatic glycogen storage and, when co-ingested with glucose, enhances post-exercise hepatic glycogen synthesis when compared with glucose alone. Despite this, the effects of fructose within a high-carbohydrate breakfast following overnight fasting (where the metabolic and hormonal environment is markedly different) remain unknown.
As such, the present study aims to assess 1) the effect of a high-carbohydrate breakfast diet on liver glycogen storage and 2) the effect of fructose content on liver glycogen storage.
To achieve our aims, participants will complete three experimental conditions in a randomised, counterbalanced order: 1) no breakfast (control), 2) high carbohydrate breakfast (3 g/kg of body mass) (0% fructose), and 3) high carbohydrate breakfast (3 g/kg of body mass) (50% fructose). Hepatic glycogen concentrations will be quantified using non-invasive 13C magnetic resonance spectroscopy (MRS), with magnetic resonance imaging (MRI) used to assess liver volume and gastric volume. Secondary measures will include circulating metabolic and hormonal responses assessed via venous blood sampling. Primary and secondary outcomes will be compared across conditions to determine whether fructose co-ingestion alters hepatic glycogen storage relative to glucose intake and fasting. This study will provide mechanistic insight into the role of fructose in promoting hepatic glycogen synthesis.
- Being tested
- No breakfast, Breakfast (0% Fructose), Breakfast (50% fructose)
- Keywords
- Glucose, Fructose, Liver glycogen storage, Magnetic resonance spectroscopy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No breakfastDietary supplement
Participants will come in and receive no breakfast, which will act as a control group.
Breakfast (0% Fructose)Dietary supplement
Participants will receive a breakfast of 3g/kg of body mass of carbohydrate with 0% fructose content.
Breakfast (50% fructose)Dietary supplement
Participants will receive a breakfast of 3g/kg of body mass of carbohydrate with 50% fructose content.
| Study group | Role | What they receive |
|---|---|---|
| Control | Experimental | No breakfast Receives: Dietary Supplement: No breakfast |
| 0% fructose | Experimental | Breakfast containing 0% fructose Receives: Dietary Supplement: Breakfast (0% Fructose) |
| 50% fructose | Experimental | Breakfast containing 50% fructose Receives: Dietary Supplement: Breakfast (50% fructose) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in liver glycogen content
The change in liver glycogen content will be determined using 13C magnetic resonance spectroscopy
Measured: 3 hours
Secondary outcomes (9)
Total carbohydrate oxidation
Total carbohydrate oxidation will be measured using indirect calorimetry
Measured: 3 hours
Total fat oxidation
Total fat oxidation will be measured using indirect calorimetry
Measured: 3 hours
Stomach volume
Stomach volume will be measured using MRI
Measured: 3 hours
Plasma glucose
Measured via blood collection
Measured: 3 hours
Plasma lactate
Measured via blood collection
Measured: 3 hours
Plasma insulin
Measured via blood collection
Measured: 3 hours
Plasma glucagon
Measured via blood collection
Measured: 3 hours
Gastrointestinal symptoms
Participants will be asked to rate how they are feeling on a scale of 0-10 (0 = no discomfort and 10 = very severe discomfort) on whether they feel nauseous, having any regurgitation, stomach fullness, experiencing any cramps and if they have an urge to defecate.
Measured: 3 hours
Appetite
To measure appetite (which will include being asked on hunger, fullness, satisfaction and prospective food consumption), participants will be shown a 100mm visual analog scale, which will have descriptors on both ends (e.g., I am not hungry at all, and I have never been hungrier in my life), and they will rate their appetite by drawing an intersecting vertical line along the horizontal line. The previous rating will be hidden to prevent the influence of a prior rating on the subsequent reporting.
Measured: 3 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Mar 2026
- Study startMar 2026 (estimated)
- Primary completionDec 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Carbohydrate MetabolismStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Manchester Metropolitan University
- Sponsor type
- University, hospital or other
- Collaborators
- Cargill, The University of Bath
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07476989
- Sponsor's protocol ID
- 84304
- Status last verified
- Mar 2026
- First submitted
- 25 Feb 2026
- Last updated
- 17 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of a Dual-Source High-Carbohydrate Breakfast on Hepatic Glycogen Storage Following an Overnight Fast.
- ClinicalTrials.gov ID
- NCT07476989
- Acronym / sponsor ID
- 84304
- Keywords
- Glucose, Fructose, Liver glycogen storage, Magnetic resonance spectroscopy
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Manchester Metropolitan UniversityUniversity, hospital or other
- Collaborators
- Cargill, The University of Bath
- Study start
- Mar 2026 (estimated)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 17 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is looking at whether eating a breakfast which has two different sources of carbohydrates, glucose and fructose (found in foods like honey and fruits), can increase how much glycogen can be stored in the liver. Glucose is a type of sugar that the body uses to provide energy during exercise. When it is not circulating in the blood, it is stored in the muscles and liver. The stored version of glucose is often referred to as glycogen. When the body needs energy, for example, it will break down glycogen into glucose so that it can be used as fuel.
Muscle and liver glycogen stores are vital in providing energy during prolonged exercise, and strenuous activity can rapidly deplete these stores, leading to increased fatigue and a decline in performance. Liver glycogen, however, is particularly important because it controls blood glucose levels. This is important because the brain and other organs are constantly relying on the supply of glucose to function properly.
When sleeping, the body goes through a natural period of fasting. During this period, the liver gradually breaks down its glycogen stores to release glucose into the bloodstream. Because of this, following sleep, liver glycogen stores are automatically low (which is why having breakfast is important). There is research to suggest that eating a high-carbohydrate breakfast can prevent further declines in liver glycogen; however, it is not known if eating different types of carbohydrates within the breakfast (glucose and fructose together) will affect the liver's ability to store glycogen. This research will aid in understanding optimal ways to increase liver glycogen stores before performing exercise, which may influence exercise performance.
Therefore, the main aim of this study is:
- Investigate whether a high fructose breakfast will increase liver glycogen storage
To achieve this, participants will be recruited to complete a randomised crossover study where they will undertake three different conditions. All laboratory trials will take place at the Manchester Metropolitan University Institute of Sport.
- No breakfast (Control)
- 3 g/kg of body mass of carbohydrate (of which contains 0% fructose)
- 3 g/kg of body mass of carbohydrate (of which contains50% fructose)
Liver glycogen stores will be measured using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). The investigators will measure liver glycogen content, liver volume, and stomach volume. Blood samples will also be taken to measure different metabolic hormone responses.
Detailed description
Glycogen stores in the muscle and liver play a crucial role in providing fuel during prolonged exercise and strenuous activities, which can rapidly deplete these stores, leading to increased fatigue and reduced performance. During prolonged exercise, liver glycogen is broken down to maintain blood glucose (sugar) levels and provide an important fuel source for the exercising muscles. Accordingly, liver glycogen is important for our ability to perform prolonged endurance exercise.
Following sleep, the body is placed under a natural period of fasting; because of this, the body's main source of fuel derives from liver glycogen stores, meaning hepatic glycogen stores decline sufficiently during this period. Accordingly, without sufficient pre-exercise carbohydrate intake, athletes begin training or competition with reduced liver glycogen availability, which can impair their ability to maintain blood glucose during prolonged exercise and may result in hypoglycaemia and subsequent fatigue. Whilst current guidelines suggest that pre-exercise carbohydrate intake may support the replenishment of depleted liver glycogen stores, it is currently unclear whether the composition of carbohydrates contained within the breakfast meal may impact the ability of the liver to store glycogen.
Fructose is primarily metabolised in the liver and enters hepatic carbohydrate metabolism downstream to key regulatory steps in glycolysis. Research has shown that fructose preferentially contributes to hepatic glycogen storage and, when co-ingested with glucose, enhances post-exercise hepatic glycogen synthesis when compared with glucose alone. Despite this, the effects of fructose within a high-carbohydrate breakfast following overnight fasting (where the metabolic and hormonal environment is markedly different) remain unknown.
As such, the present study aims to assess 1) the effect of a high-carbohydrate breakfast diet on liver glycogen storage and 2) the effect of fructose content on liver glycogen storage.
To achieve our aims, participants will complete three experimental conditions in a randomised, counterbalanced order: 1) no breakfast (control), 2) high carbohydrate breakfast (3 g/kg of body mass) (0% fructose), and 3) high carbohydrate breakfast (3 g/kg of body mass) (50% fructose). Hepatic glycogen concentrations will be quantified using non-invasive 13C magnetic resonance spectroscopy (MRS), with magnetic resonance imaging (MRI) used to assess liver volume and gastric volume. Secondary measures will include circulating metabolic and hormonal responses assessed via venous blood sampling. Primary and secondary outcomes will be compared across conditions to determine whether fructose co-ingestion alters hepatic glycogen storage relative to glucose intake and fasting. This study will provide mechanistic insight into the role of fructose in promoting hepatic glycogen synthesis.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Control | Experimental | Dietary Supplement: No breakfastNo breakfast |
| 0% fructose | Experimental | Dietary Supplement: Breakfast (0% Fructose)Breakfast containing 0% fructose |
| 50% fructose | Experimental | Dietary Supplement: Breakfast (50% fructose)Breakfast containing 50% fructose |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- A male (at birth) aged between 18 and 45.
- Regularly training for a specific sport (must include cycling) at least 3 times per week (with the purpose of competing).
- VO2 peak >50 (ml.kg.min)
- A current non-smoker/vaper (must not have smoked or vaped within the last 6 months)
- Do not have any medical conditions or are taking any medications or supplements which can affect the study's outcome measures.
Key exclusion criteria (7 listed)
- Are not a male (at birth) aged between 18 and 45.
- Do not regularly train for a specific sport (must include cycling) at least 3 times per week (with the purpose of competing).
- Does not have a VO2 max/peak >50 (ml.kg.min)
- A current smoker/vaper (must not have smoked or vaped within the last 6 months)
- Have any medical conditions or are taking any medications or supplements which can affect the study's outcome measures
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No breakfastParticipants will come in and receive no breakfast, which will act as a control group. | Dietary supplement | Control |
| Breakfast (0% Fructose)Participants will receive a breakfast of 3g/kg of body mass of carbohydrate with 0% fructose content. | Dietary supplement | 0% fructose |
| Breakfast (50% fructose)Participants will receive a breakfast of 3g/kg of body mass of carbohydrate with 50% fructose content. | Dietary supplement | 50% fructose |
Primary outcome
Change in liver glycogen content
Time frame: 3 hours
The change in liver glycogen content will be determined using 13C magnetic resonance spectroscopy
9 secondary outcomes
Total carbohydrate oxidation
Time frame: 3 hours
Total fat oxidation
Time frame: 3 hours
Stomach volume
Time frame: 3 hours
Plasma glucose
Time frame: 3 hours
Plasma lactate
Time frame: 3 hours
Plasma insulin
Time frame: 3 hours
Plasma glucagon
Time frame: 3 hours
Gastrointestinal symptoms
Time frame: 3 hours
Appetite
Time frame: 3 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Mar 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A study testing No breakfast, Breakfast (0% Fructose) and Breakfast (50% fructose) in people with Carbohydrate Metabolism and Hepatic Glycogen Storage, run by Manchester Metropolitan University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 17 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in liver glycogen content (time frame: 3 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Mar 2026.