Glucose and Lipid MetabolismNCT07250191
The Effects of 24-hour Fasting or Carbohydrate Restriction on Postprandial Metabolic Responses
A study testing Fasting and Carbohydrate restriction in people with Glucose and Lipid Metabolism, run by University of Bath at 1 site in United Kingdom.
Trial summary
Most individuals spend the majority of the day in a fed state, making postprandial blood glucose and lipid regulation a central component of metabolic health. Short periods of fasting or reduced carbohydrate intake can occur frequently in daily life, whether through intentional dietary practices (e.g. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Glucose and Lipid Metabolism
- What is being tested?
- Fasting and Carbohydrate restriction
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 16 Oct 2023to 6 Nov 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Aged between 18-40 years
- Have a BMI of 18.5-29.9 kg/m2
Who cannot join
- Diagnosed with any major chronic conditions (e.g. type 2 diabetes, coronary heart disease, cancer, chronic kidney disease, etc.)
- Use of medication that may interfere with study outcomes (e.g. glucose or lipid-lowering medications)
- Currently or recently pregnant (within last 6 months), planning to get pregnant or currently lactating
- Has a habitually low carbohydrate intake (<150g carbohydrates/day)
- Current or previous eating disorder
- Has donated more than 500ml of blood in the last 3 months prior to the initial laboratory visit
Show all 9Show fewer
- Insufficient mental capacity or language skills to independently understand and follow the study protocol
- Has an irregular sleeping pattern (e.g. due to undertaking night-shift work)
- Any other condition, concurrent intervention or behaviour deemed either to pose undue personal risk to the participant or to introduce bias into the experiment
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Acute Effects of Energy and Carbohydrate Restriction on Postprandial Metabolism
Most individuals spend the majority of the day in a fed state, making postprandial blood glucose and lipid regulation a central component of metabolic health. Short periods of fasting or reduced carbohydrate intake can occur frequently in daily life, whether through intentional dietary practices (e.g. intermittent fasting), cultural or religious traditions, or unstructured eating patterns. These periods can induce measurable metabolic changes, but the acute effects of a single 24-hour period of fasting or carbohydrate restriction on postprandial metabolism upon refeeding remain poorly characterised.
This study will examine how 24 hours of either complete fasting or low carbohydrate intake without energy restriction influence postprandial blood glucose and lipid concentrations, as well as related metabolic markers, in healthy adults, in comparison to a habitual high carbohydrate control diet. Participants will complete all three conditions in a randomised order, consuming a standardised meal test after each 24-hour condition. Repeated blood sampling and gas exchange measurements will be carried out to assess postprandial metabolic responses.
The aim of this study is to characterise whether acute periods of fasting and low carbohydrate restriction elicit distinct or comparable alterations in postprandial metabolic responses. A clearer understanding of these acute physiological effects can help inform how variations in eating patterns influence glucose and lipid handling in individuals without metabolic disease.
- Conditions
- Glucose and Lipid Metabolism
- Being tested
- Fasting, Carbohydrate restriction
- Keywords
- carbohydrate restriction, fasting, intermittent energy restriction
- Medical subject headings
- Fasting
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FastingBehavioural
No food intake for 24 hours
Carbohydrate restrictionBehavioural
Also called Ketogenic diet
Restriction of dietary carbohydrate to ≤5% of total energy intake for 24 hours
| Study group | Role | What they receive |
|---|---|---|
| Habital control diet | No intervention | 100% of energy requirements, ≥150 carbohydrate/day |
| Fasting | Experimental | No energy intake Receives: Behavioral: Fasting |
| Carbohydrate Restriction | Experimental | 100% of energy requirements, ≤20g carbohydrate Receives: Behavioral: Carbohydrate restriction |
What is being measured
The primary outcome is the main question the study is designed to answer.
Triglyceride Concentration
Plasma triglyceride concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
Measured: After each 24-hour dietary condition
Glucose Concentration
Plasma glucose concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
Measured: After each 24-hour dietary condition
Secondary outcomes (4)
Insulin Concentration
Plasma insulin concentrations assessed postprandially for 2 hours after a mixed meal test
Measured: After each 24-hour dietary condition
Non-esterified Fatty Acid Concentration
Plasma non-esterified fatty acid concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
Measured: After each 24-hour dietary condition
Beta-hydroxybutyrate Concentration
Plasma beta-hydroxybutyrate concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
Measured: After each 24-hour dietary condition
Substrate Oxidation
Lipid and carbohydrate oxidation assessed via indirect calorimetry at baseline and during 2-hour mixed meal test
Measured: After each 24-hour dietary condition
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2025
- Study start16 Oct 2023
- Primary completion20 Jan 2024
- Study completion6 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Glucose and Lipid 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
- 16 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Bath
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Guoda Karoblyte, University of Bath
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07250191
- Sponsor's protocol ID
- 0590
- Status last verified
- Nov 2025
- First submitted
- 18 Nov 2025
- Last updated
- 26 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Acute Effects of Energy and Carbohydrate Restriction on Postprandial Metabolism
- ClinicalTrials.gov ID
- NCT07250191
- Acronym / sponsor ID
- 0590
- Conditions
- Glucose and Lipid Metabolism
- Keywords
- carbohydrate restriction, fasting, intermittent energy restriction
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 16 participants (actual)
- Lead sponsor
- University of BathUniversity, hospital or other
- Study start
- 16 Oct 2023 (actual)
- Primary completion
- 20 Jan 2024 (actual)
- Study completion
- 6 Nov 2025 (actual)
- First posted
- 26 Nov 2025 (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.
Most individuals spend the majority of the day in a fed state, making postprandial blood glucose and lipid regulation a central component of metabolic health. Short periods of fasting or reduced carbohydrate intake can occur frequently in daily life, whether through intentional dietary practices (e.g. intermittent fasting), cultural or religious traditions, or unstructured eating patterns. These periods can induce measurable metabolic changes, but the acute effects of a single 24-hour period of fasting or carbohydrate restriction on postprandial metabolism upon refeeding remain poorly characterised.
This study will examine how 24 hours of either complete fasting or low carbohydrate intake without energy restriction influence postprandial blood glucose and lipid concentrations, as well as related metabolic markers, in healthy adults, in comparison to a habitual high carbohydrate control diet. Participants will complete all three conditions in a randomised order, consuming a standardised meal test after each 24-hour condition. Repeated blood sampling and gas exchange measurements will be carried out to assess postprandial metabolic responses.
The aim of this study is to characterise whether acute periods of fasting and low carbohydrate restriction elicit distinct or comparable alterations in postprandial metabolic responses. A clearer understanding of these acute physiological effects can help inform how variations in eating patterns influence glucose and lipid handling in individuals without metabolic disease.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Habital control diet | No intervention | –100% of energy requirements, ≥150 carbohydrate/day |
| Fasting | Experimental | Behavioral: FastingNo energy intake |
| Carbohydrate Restriction | Experimental | Behavioral: Carbohydrate restriction100% of energy requirements, ≤20g carbohydrate |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Aged between 18-40 years
- Have a BMI of 18.5-29.9 kg/m2
Key exclusion criteria (9 listed)
- Diagnosed with any major chronic conditions (e.g. type 2 diabetes, coronary heart disease, cancer, chronic kidney disease, etc.)
- Use of medication that may interfere with study outcomes (e.g. glucose or lipid-lowering medications)
- Currently or recently pregnant (within last 6 months), planning to get pregnant or currently lactating
- Has a habitually low carbohydrate intake (<150g carbohydrates/day)
- Current or previous eating disorder
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 |
|---|---|---|
| FastingNo food intake for 24 hours | Behavioural | Fasting |
| Carbohydrate restrictionAlso: Ketogenic dietRestriction of dietary carbohydrate to ≤5% of total energy intake for 24 hours | Behavioural | Carbohydrate Restriction |
Primary outcome
Triglyceride Concentration
Time frame: After each 24-hour dietary condition
Plasma triglyceride concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
Glucose Concentration
Time frame: After each 24-hour dietary condition
Plasma glucose concentrations assessed at baseline and postprandially for 2 hours after a mixed meal test
4 secondary outcomes
Insulin Concentration
Time frame: After each 24-hour dietary condition
Non-esterified Fatty Acid Concentration
Time frame: After each 24-hour dietary condition
Beta-hydroxybutyrate Concentration
Time frame: After each 24-hour dietary condition
Substrate Oxidation
Time frame: After each 24-hour dietary condition
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Nov 2025.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fasting and Carbohydrate restriction in people with Glucose and Lipid Metabolism, run by University of Bath at 1 site in United Kingdom.
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 2 inclusion and 9 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: finished, as of the sponsor's last update on 26 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Triglyceride Concentration (time frame: After each 24-hour dietary condition). The study lists 2 primary outcomes in all. 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 26 Nov 2025.