Healthy ParticipantsPPGRBNCT07158762
Blood Glucose Levels After Bread Consumption Between Participants With Normal Weight and Overweight/Obesity
A study testing White bread and Wholemeal bread in people with Healthy Participants and Normal Weight Adults, run by City, University of London at 1 site in United Kingdom.
Trial summary
Obesity and increased blood glucose peaks are risk factors for type 2 diabetes mellitus (T2DM). Few studies have explored whether increased body fat contributes to higher blood glucose peaks after food consumption. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Participants, Normal Weight Adults, Overweight or Obese Adults
- What is being tested?
- White bread and Wholemeal bread
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 May 2022to 31 Jul 2022
- 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 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- healthy adults of 18 - 50 years
Who cannot join
- participants with diabetes
- digestive system diseases
- BMI < 18.5 kg/m2
- coeliac disease
- other chronic diseases
- blood clotting issues
- those who could not consume the study meals due to food allergies or other reasons
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Association of Postprandial Blood Glucose Levels With Body Weight in Adults
Obesity and increased blood glucose peaks are risk factors for type 2 diabetes mellitus (T2DM). Few studies have explored whether increased body fat contributes to higher blood glucose peaks after food consumption.
This study aimed to investigate differences in blood glucose levels between healthy adults with normal weight and those with overweight/obesity after consuming two commercially available breads (white and wholemeal) with different dietary fibre contents.
In this study, 20 healthy adults (10 normal weight, 10 overweight/obese) consumed two slices of white bread (100 g, fibre 3.6 g) or wholemeal bread (88 g, fibre 5.6 g) alongside 150 ml of orange juice and 10 g of butter on separate visits in random order after fasting for 8-12 hours. Blood glucose concentration was measured while fasting (before bread consumption) and at 30, 60, 90, and 120 minutes after consumption using finger-prick tests. Information on age, gender, ethnicity, body mass index (BMI), and body fat percentage (BF%) was also collected.
Read the detailed description
Introduction
Postprandial glycaemic response (PPGR) is an independent risk factor for type 2 diabetes mellitus (T2DM), and postprandial hyperglycaemia is the first detectable metabolic alteration in the progression from prediabetes to T2DM. T2DM is a multifactorial disease, with overweight and obesity being major risk factors.
Previous evidence shows inconsistent results regarding the association between BMI (few studies used BF%) and PPGRs. Some studies found no significant difference in the incremental area under the curve (iAUC) of PPGRs between participants with normal weight and overweight/obesity after bread consumption or glucose solution ingestion. Other studies similarly reported no differences after processed orange juice ingestion or a high-fat meal.
Bread is a staple food in the UK, with white bread being the most consumed, followed by wholemeal bread. Wholemeal bread is generally considered healthier than white bread due to its higher content of dietary fibre, phytochemicals, and some minerals and vitamins. Interestingly, some studies found no significant differences in PPGRs between wholemeal and white breads, despite the higher fibre content of wholemeal bread. This may be due to the predominance of insoluble fibre in wholemeal flour, which does not affect postprandial glycaemia, whereas soluble, viscous fibre is known to slow gastric emptying and glucose absorption, thereby attenuating glycaemic spikes. However, few studies have tested commercially available breads, which typically contain around 7 g (wholemeal) and 2.9 g (white) of dietary fibre per 100 g.
The primary aim of this study is to determine whether individuals with overweight or obesity exhibit higher PPGRs compared to individuals with normal weight following the consumption of commercially available white and wholemeal breads sold in UK supermarkets. The secondary aim is to assess whether wholemeal bread consumption attenuates PPGRs compared to white bread, irrespective of BMI or BF%.
Methods
Ethics approval
The study was approved by the Coventry University Ethics Committee (Ref P136390).
Participants
Twenty participants will be recruited using purposive and convenience sampling via a recruitment advert circulated by email and word of mouth among university staff and students. Normal weight (BMI 18.5-24.9 kg/m²) and overweight/obesity (BMI ≥ 25 kg/m²) were defined according to National Institute for Health and Care Excellence (NICE).
Inclusion criteria: healthy adults aged 18-50 years. Exclusion criteria: diabetes, digestive system diseases, BMI < 18.5 kg/m², coeliac disease, other chronic diseases, blood clotting disorders, or inability to consume the study meals due to food allergy or other reasons.
Eligibility will be screened via a health and lifestyle questionnaire.
Study design
This is an acute, randomised, non-blinded crossover trial. Eligible participants will attend two visits (at least 48 hours apart). They will be asked to fast for 8-12 hours (water only) prior to each visit.
On each visit, participants will be provided with meals containing either white bread (WB) or wholemeal bread (WMB) in random order. The bread type for the first visit will be determined by coin toss: heads = WB, tails = WMB. Participants will consume two slices of bread (white or wholemeal) alongside 150 ml of pure orange juice and 10 g of butter to mimic a real-life scenario and enhance palatability. All food and drink items will be purchased from TESCO supermarket (Welwyn Garden City, United Kingdom).
Postprandial blood glucose will be measured at 0 (fasting), 30, 60, 90, and 120 minutes by finger prick, performed by the researcher using the BIOSEN Blood Glucose/Lactate Analyser (EKF Diagnostics, Cardiff). Participants will be instructed to consume the meal within 10 minutes, remain sedentary, and refrain from eating or drinking during the study period. Mobile alarms will be used to ensure blood samples are collected on time.
Participants will also be asked to follow a similar dinner, avoid intensive physical activity and alcohol, and obtain adequate sleep the night before each visit. Names, email addresses, and mobile numbers will be collected for appointment purposes, and self-reported demographic variables (age, gender, and ethnicity) will also be collected.
The treatment allocation (bread type) will not be blinded to AC and YX, who conducted the study, or to participants (non-blinded), but will be blinded to HD, who analysed the data.
Outcome measures
PPGRs will be reported as iAUCs and peak values (PVs) after the meals for up to 2 hours. iAUC will be calculated using trapezoidal numerical integration, including only the incremental area above the fasting level.
Body height will be measured with a stadiometer, and body weight and BF% will be measured using the TANITA MC-980MA PLUS (TANITA Company, Tokyo) before the meal on the first visit only.
Data analysis
The sample size was informed by a similar study design and calculated using G*Power software (version 3.1.9.7, Düsseldorf, Germany), selecting F-test, ANOVA: repeated measures, within-between interaction. Twenty participants were required to detect an effect size of 0.3 with 90% power at a significance level of 0.05.
Categorical data will be presented as frequency (n) and percentage (%). Continuous data will be presented as mean ± standard deviation (SD). Differences in age, BMI, and BF% between the two groups will be analysed using independent-samples t-tests. Gender and ethnicity distributions between groups will be analysed using the Chi-squared test.
Differences in iAUC and PVs between the two body weight groups (between-subject factor) and between WB and WMB conditions (within-subject factor) will be analysed using a two-way repeated-measures ANOVA. Pearson's correlation will be used to analyse associations of BMI and BF% with iAUCs and PVs after white and wholemeal bread consumption separately. Normality of continuous data will be assessed using the Kolmogorov-Smirnov test. Statistical significance is set at P ≤ 0.05 (two-tailed).
- Being tested
- White bread, Wholemeal bread
- Keywords
- postprandial glycaemic response, bread, body mass index, body fat percentage
- Medical subject headings
- Overweight
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
White breadOther
Two slices of white bread consumption along with 150 ml of pure orange juice and 10 g of butter
Wholemeal breadOther
Two slices of wholemeal bread consumption along with 150 ml of pure orange juice and 10 g of butter
| Study group | Role | What they receive |
|---|---|---|
| Participants with normal weight | Active comparator | Healthy participants with a body mass index between 18.5-24.9 kg/m2. Receives: Other: White bread; Other: Wholemeal bread |
| Participants with overweight or obesity | Experimental | Healthy participants with a body mass index ≥ 25 kg/m2 Receives: Other: White bread; Other: Wholemeal bread |
What is being measured
The primary outcome is the main question the study is designed to answer.
Postprandial glycaemic response
Postprandial blood glucose was measured at 0 (fasting), 30, 60, 90 and 120 minutes by finger prick performed by the researcher using Biosen Blood Glucose/Lactate Analyser (EKF Diagnostics, Cardiff).
Measured: 2 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Sep 2025
- Study start1 May 2022
- Primary completion31 Jul 2022
- Study completion31 Jul 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy ParticipantsStudies 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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- City, University of London
- Sponsor type
- University, hospital or other
- Collaborators
- Coventry University
- Responsible party
- Sponsor
- Investigators
- Yizhi Xu, PhD, Principal investigator, Coventry University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07158762
- Sponsor's protocol ID
- P136390
- Other IDs
- Ref 71978
- Acronym
- PPGRB
- Status last verified
- Sep 2025
- First submitted
- 26 Aug 2025
- Last updated
- 8 Sep 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 8 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Association of Postprandial Blood Glucose Levels With Body Weight in Adults
- ClinicalTrials.gov ID
- NCT07158762
- Acronym / sponsor ID
- PPGRB / P136390
- Keywords
- postprandial glycaemic response, bread, body mass index, body fat percentage
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- City, University of LondonUniversity, hospital or other
- Collaborators
- Coventry University
- Study start
- 1 May 2022 (actual)
- Primary completion
- 31 Jul 2022 (actual)
- Study completion
- 31 Jul 2022 (actual)
- First posted
- 8 Sep 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.
Obesity and increased blood glucose peaks are risk factors for type 2 diabetes mellitus (T2DM). Few studies have explored whether increased body fat contributes to higher blood glucose peaks after food consumption.
This study aimed to investigate differences in blood glucose levels between healthy adults with normal weight and those with overweight/obesity after consuming two commercially available breads (white and wholemeal) with different dietary fibre contents.
In this study, 20 healthy adults (10 normal weight, 10 overweight/obese) consumed two slices of white bread (100 g, fibre 3.6 g) or wholemeal bread (88 g, fibre 5.6 g) alongside 150 ml of orange juice and 10 g of butter on separate visits in random order after fasting for 8-12 hours. Blood glucose concentration was measured while fasting (before bread consumption) and at 30, 60, 90, and 120 minutes after consumption using finger-prick tests. Information on age, gender, ethnicity, body mass index (BMI), and body fat percentage (BF%) was also collected.
Detailed description
Introduction
Postprandial glycaemic response (PPGR) is an independent risk factor for type 2 diabetes mellitus (T2DM), and postprandial hyperglycaemia is the first detectable metabolic alteration in the progression from prediabetes to T2DM. T2DM is a multifactorial disease, with overweight and obesity being major risk factors.
Previous evidence shows inconsistent results regarding the association between BMI (few studies used BF%) and PPGRs. Some studies found no significant difference in the incremental area under the curve (iAUC) of PPGRs between participants with normal weight and overweight/obesity after bread consumption or glucose solution ingestion. Other studies similarly reported no differences after processed orange juice ingestion or a high-fat meal.
Bread is a staple food in the UK, with white bread being the most consumed, followed by wholemeal bread. Wholemeal bread is generally considered healthier than white bread due to its higher content of dietary fibre, phytochemicals, and some minerals and vitamins. Interestingly, some studies found no significant differences in PPGRs between wholemeal and white breads, despite the higher fibre content of wholemeal bread. This may be due to the predominance of insoluble fibre in wholemeal flour, which does not affect postprandial glycaemia, whereas soluble, viscous fibre is known to slow gastric emptying and glucose absorption, thereby attenuating glycaemic spikes. However, few studies have tested commercially available breads, which typically contain around 7 g (wholemeal) and 2.9 g (white) of dietary fibre per 100 g.
The primary aim of this study is to determine whether individuals with overweight or obesity exhibit higher PPGRs compared to individuals with normal weight following the consumption of commercially available white and wholemeal breads sold in UK supermarkets. The secondary aim is to assess whether wholemeal bread consumption attenuates PPGRs compared to white bread, irrespective of BMI or BF%.
Methods
Ethics approval
The study was approved by the Coventry University Ethics Committee (Ref P136390).
Participants
Twenty participants will be recruited using purposive and convenience sampling via a recruitment advert circulated by email and word of mouth among university staff and students. Normal weight (BMI 18.5-24.9 kg/m²) and overweight/obesity (BMI ≥ 25 kg/m²) were defined according to National Institute for Health and Care Excellence (NICE).
Inclusion criteria: healthy adults aged 18-50 years. Exclusion criteria: diabetes, digestive system diseases, BMI < 18.5 kg/m², coeliac disease, other chronic diseases, blood clotting disorders, or inability to consume the study meals due to food allergy or other reasons.
Eligibility will be screened via a health and lifestyle questionnaire.
Study design
This is an acute, randomised, non-blinded crossover trial. Eligible participants will attend two visits (at least 48 hours apart). They will be asked to fast for 8-12 hours (water only) prior to each visit.
On each visit, participants will be provided with meals containing either white bread (WB) or wholemeal bread (WMB) in random order. The bread type for the first visit will be determined by coin toss: heads = WB, tails = WMB. Participants will consume two slices of bread (white or wholemeal) alongside 150 ml of pure orange juice and 10 g of butter to mimic a real-life scenario and enhance palatability. All food and drink items will be purchased from TESCO supermarket (Welwyn Garden City, United Kingdom).
Postprandial blood glucose will be measured at 0 (fasting), 30, 60, 90, and 120 minutes by finger prick, performed by the researcher using the BIOSEN Blood Glucose/Lactate Analyser (EKF Diagnostics, Cardiff). Participants will be instructed to consume the meal within 10 minutes, remain sedentary, and refrain from eating or drinking during the study period. Mobile alarms will be used to ensure blood samples are collected on time.
Participants will also be asked to follow a similar dinner, avoid intensive physical activity and alcohol, and obtain adequate sleep the night before each visit. Names, email addresses, and mobile numbers will be collected for appointment purposes, and self-reported demographic variables (age, gender, and ethnicity) will also be collected.
The treatment allocation (bread type) will not be blinded to AC and YX, who conducted the study, or to participants (non-blinded), but will be blinded to HD, who analysed the data.
Outcome measures
PPGRs will be reported as iAUCs and peak values (PVs) after the meals for up to 2 hours. iAUC will be calculated using trapezoidal numerical integration, including only the incremental area above the fasting level.
Body height will be measured with a stadiometer, and body weight and BF% will be measured using the TANITA MC-980MA PLUS (TANITA Company, Tokyo) before the meal on the first visit only.
Data analysis
The sample size was informed by a similar study design and calculated using G*Power software (version 3.1.9.7, Düsseldorf, Germany), selecting F-test, ANOVA: repeated measures, within-between interaction. Twenty participants were required to detect an effect size of 0.3 with 90% power at a significance level of 0.05.
Categorical data will be presented as frequency (n) and percentage (%). Continuous data will be presented as mean ± standard deviation (SD). Differences in age, BMI, and BF% between the two groups will be analysed using independent-samples t-tests. Gender and ethnicity distributions between groups will be analysed using the Chi-squared test.
Differences in iAUC and PVs between the two body weight groups (between-subject factor) and between WB and WMB conditions (within-subject factor) will be analysed using a two-way repeated-measures ANOVA. Pearson's correlation will be used to analyse associations of BMI and BF% with iAUCs and PVs after white and wholemeal bread consumption separately. Normality of continuous data will be assessed using the Kolmogorov-Smirnov test. Statistical significance is set at P ≤ 0.05 (two-tailed).
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Participants with normal weight | Active comparator | Other: White bread, Other: Wholemeal breadHealthy participants with a body mass index between 18.5-24.9 kg/m2. |
| Participants with overweight or obesity | Experimental | Other: White bread, Other: Wholemeal breadHealthy participants with a body mass index ≥ 25 kg/m2 |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- healthy adults of 18 - 50 years
Key exclusion criteria (7 listed)
- participants with diabetes
- digestive system diseases
- BMI < 18.5 kg/m2
- coeliac disease
- other chronic diseases
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 |
|---|---|---|
| White breadTwo slices of white bread consumption along with 150 ml of pure orange juice and 10 g of butter | Other | Participants with normal weight, Participants with overweight or obesity |
| Wholemeal breadTwo slices of wholemeal bread consumption along with 150 ml of pure orange juice and 10 g of butter | Other | Participants with normal weight, Participants with overweight or obesity |
Primary outcome
Postprandial glycaemic response
Time frame: 2 hours
Postprandial blood glucose was measured at 0 (fasting), 30, 60, 90 and 120 minutes by finger prick performed by the researcher using Biosen Blood Glucose/Lactate Analyser (EKF Diagnostics, Cardiff).
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 8 Sep 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.
Yizhi Xu, PhD principal investigator
Coventry University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing White bread and Wholemeal bread in people with Healthy Participants and Normal Weight Adults, run by City, University of London 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 1 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: finished, as of the sponsor's last update on 8 Sep 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?
Postprandial glycaemic response (time frame: 2 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 8 Sep 2025.