Type 2 DiabetesFRUIT2NCT07376226
Effects of Whole Fruit on Blood Sugar in People With Type 2 Diabetes
A study testing Whole Fruit in people with Type 2 Diabetes, run by Harvard School of Public Health (HSPH) at 1 site in United States.
Trial summary
This study will determine the effects of consuming whole fruit on blood sugar control, liver fat, and cardiovascular health in adults with type 2 diabetes who are not treated with insulin. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Type 2 Diabetes
- What is being tested?
- Whole Fruit
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 1 siteUnited States
- Study dates
- Sep 2026to Apr 2028
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged ≥18 years
- Diagnosed with type 2 diabetes
- HbA1c between 6.5-12.0%
- Fasting C-peptide level ≥0.5 ng/ml, indicating the patient does not have beta-cell failure, as measured at screening
Who cannot join
- On insulin
- Evidence of latent autoimmune diabetes (LADA) or maturity-onset diabetes of the young (MODY)
- Estimated glomerular filtration rate (eGFR) <45 ml/min per 1.73 m²
- Heart attack in the past 6 months or severe/unstable heart failure
- On weight loss medication, including GLP-1 receptor agonists (e.g., semaglutide, dulaglutide)
- Change in the dosage of a chronic medication that may affect study endpoints within the past 3 months
Show all 16Show fewer
- Clinically significant laboratory abnormality (e.g., abnormal hemoglobin levels)
- Significant gastrointestinal disease, major gastrointestinal surgery, or gallstones
- Significant cardiovascular, renal, cardiac, liver, lung, adrenal, or nervous system disease that might compromise participant safety or data validity
- Evidence of cancer (other than non-melanoma skin cancer) within the last 5 years
- Lost or gained more than 5 lbs (or more than 2% of body weight if the patient weighs >250 lbs) of weight in the past 2 months
- Pregnant, planning to become pregnant in the next 6 months, or breastfeeding
- Major psychiatric condition that would affect the ability to participate in the study
- Not able to eat the provided study meals (e.g., food allergies)
- Behavioral factors or circumstances that may impede adherence to the dietary intervention
- Not able to undergo the MRI scan (e.g., due to claustrophobia, implanted metal objects, or body girth ≥60 cm)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Harvard T. H. Chan School of Public Health
Boston, Massachusetts, 02115
Kathleen Johnson, 617-998-6333, fruit2@hsph.harvard.edu
Courtney M Peterson, PhD
About this study
Official title: Effects of Whole Fruit on Glycemic Control, Liver Fat, and Cardiovascular Disease Risk Factors in Adults With Type 2 Diabetes
This study will determine the effects of consuming whole fruit on blood sugar control, liver fat, and cardiovascular health in adults with type 2 diabetes who are not treated with insulin.
Read the detailed description
Diabetes is one of the top three drivers of healthcare costs in the U.S., and nearly half of Americans will develop either diabetes or prediabetes in their lifetime. It is therefore critical to find new strategies to treat or reverse diabetes.
One such approach is adopting a healthy diet, which can dramatically improve blood sugar levels in adults with type 2 diabetes and even induce diabetes remission in some patients. Despite this, not much is known about which food groups are most effective at improving blood sugar levels in patients with diabetes.
Although individuals with type 2 diabetes are often advised to reduce carbohydrate intake, current dietary guidelines also recommend consuming fruit and other carbohydrate-rich foods. This has led to confusion among patients and clinicians about whether eating fruit, particularly in larger amounts, is beneficial or harmful for blood sugar and overall health. Whole fruit differs from many other carbohydrate sources in that whole fruit is rich in fiber, vitamins, minerals, and bioactive plant compounds, while being relatively low in energy density.
Most prior research examining the effects of whole fruit in people with type 2 diabetes has been epidemiologic, focused on individual fruits, or combined whole fruit with fruit juice and/or vegetables into a single food category. As a result, it is unknown how whole fruit, as a food category, affects glycemic control and cardiovascular health.
The investigators previously found that a whole-fruit-rich, Mediterranean-style diet improved blood sugar control and blood pressure in patients with type 2 diabetes and even allowed some patients to wean off all anti-hyperglycemic medications. The investigators will conduct a follow-up study to determine the effects of whole fruit alone on glycemic control, liver fat, and cardiovascular risk factors. The study will be a single-arm controlled feeding study to determine the effects of eating a large amount of whole fruit for 17 weeks on glycemic control (Aim 1), liver fat (Aim 2a), and cardiovascular disease risk factors (Aim 2b) in patients with insulin-independent type 2 diabetes. The primary measures of glycemic control will be mean 24-hour glucose levels (as measured by continuous glucose monitoring) and mean 3-hour glucose levels (as measured during a 3-hour oral glucose tolerance test). These assessments will be supplemented by, and interpreted in light of, other glycemic outcomes, which are listed as outcomes #3-9 below.
By providing controlled, high-quality evidence, this study will determine whether whole fruit is good or bad for patients with type 2 diabetes and will improve dietary guidelines for the hundreds of millions of individuals with type 2 diabetes.
- Conditions
- Type 2 Diabetes
- Being tested
- Whole Fruit
- Keywords
- type 2 diabetes, whole fruit, dietary intervention, glycemic control, liver fat, continuous glucose monitoring, blood sugar, nutrition, fruit, glucose, insulin, blood pressure, carbohydrates, high-carbohydrate diet
- Medical subject headings
- Diabetes Mellitus, Type 2, Fatty Liver, Insulin Resistance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Whole FruitOther
Participants will consume a large amount of whole fruit for 17 weeks. During the first 6.5 weeks, participants will gradually increase the amount of whole fruit they eat by 5% every 5 days. Once they reach 50% of their calories as whole fruit, they will continue to eat 50% fruit for the remaining 10.5 weeks of the study. This is a controlled feeding study, so participants will consume fruit prepared in a metabolic kitchen. The fruit will consist of fresh fruit, dried fruit, and frozen fruit blended into smoothies. To demonstrate compliance, participants will video-record themselves eating the provided fruit. All participants will receive the same dietary intervention. Participants will otherwise continue their usual diet and lifestyle habits.
| Study group | Role | What they receive |
|---|---|---|
| Whole Fruit | Experimental | Participants will consume a large amount of whole fruit, constituting 50% of total calories. Receives: Other: Whole Fruit |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean 24-hour Glucose Levels
Average 24-hour interstitial glucose levels (mg/dl), as measured by continuous glucose monitoring (CGM). If needed, data will be adjusted for any changes in antihyperglycemic medication use, using the medication effect score (MES).
Measured: Change from baseline to week 17
Mean 3-hour Glucose Levels
Mean glucose (mg/dl) during a 3-hour oral glucose tolerance test (OGTT)
Measured: Change from baseline to week 17
Mean 3-hour Insulin
Mean insulin (mU/l) during a 3-hour OGTT
Measured: Change from baseline to week 17
Mean 3-hour C-Peptide
Mean C-Peptide (ng/ml) during a 3-hour OGTT
Measured: Change from baseline to week 17
Insulin Sensitivity
Insulin sensitivity (dl/kg/min/μU/ml) during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model
Measured: Change from baseline to week 17
Dynamic Beta-Cell Responsivity
Phi_dynamic during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model (which is a set of 5 coupled differential equations; see reference under Citations). Phi_dynamic is a measure of beta-cell responsiveness during first-phase insulin secretion. It is a dimensionless index (arbitrary units), where higher values denote greater insulin secretion
Measured: Change from baseline to week 17
Static Beta-Cell Responsivity
Phi_static during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model (which is a set of 5 coupled differential equations; see reference under Citations). Phi_static is a measure of beta-cell responsiveness during second-phase insulin secretion. The units of measure are min^-1, and higher values denote greater insulin secretion.
Measured: Change from baseline to week 17
Glycemic Variability
Measures of glucose variability derived from continuous glucose monitoring, including mean amplitude of glycemic excursions and standard deviation (mg/dl).
Measured: Change from baseline to week 17
Time-in-range Metrics from CGM
Standard time-in-range metrics, including time-below-range (TBR), time-in-range (TIR), and time-above-range (TAR), as standardized by the International Consensus on Time in Range. Values will be reported as percentages of the 24-hour day.
Measured: Change from baseline to week 17
Secondary outcomes (5)
Intrahepatic Lipid (Liver Fat)
Percentage as measured using Magnetic Resonance Spectroscopy (MRS) and 3-point M-Dixon Magnetic Resonance Imaging (MRI)
Measured: Change from baseline to week 17
Body Weight
kg
Measured: Change from baseline to week 17
Systolic and Diastolic Blood Pressure
mm Hg
Measured: Change from baseline to week 17
Heart Rate
beats per minute
Measured: Change from baseline to week 17
Lipids
Fasting total cholesterol (mg/dl), LDL cholesterol (mg/dl), HDL cholesterol (mg/dl), and triglycerides (mg/dl).
Measured: Change from baseline to week 17
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jan 2026
- Study startSep 2026 (estimated)
- Primary completionOct 2027 (estimated)
- Study completionApr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Type 2 DiabetesStudies 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
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Harvard School of Public Health (HSPH)
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Courtney Peterson, Harvard School of Public Health (HSPH)
- Investigators
- Courtney M Peterson, Principal investigator, Harvard School of Public Health (HSPH)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07376226
- Sponsor's protocol ID
- 25-1444
- Acronym
- FRUIT2
- Status last verified
- Jul 2026
- First submitted
- 22 Jan 2026
- Last updated
- 7 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Cobelli C, Dalla Man C, Toffolo G, Basu R, Vella A, Rizza R. The oral minimal model method. Diabetes. 2014 Apr;63(4):1203-13. doi: 10.2337/db13-1198.
PubMed 24651807
Study at a glance
From the registry record, last updated by the sponsor on 7 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Whole Fruit on Glycemic Control, Liver Fat, and Cardiovascular Disease Risk Factors in Adults With Type 2 Diabetes
- ClinicalTrials.gov ID
- NCT07376226
- Acronym / sponsor ID
- FRUIT2 / 25-1444
- Conditions
- Type 2 Diabetes
- Keywords
- type 2 diabetes, whole fruit, dietary intervention, glycemic control, liver fat, continuous glucose monitoring, blood sugar, nutrition
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- Harvard School of Public Health (HSPH)University, hospital or other
- Study start
- Sep 2026 (estimated)
- Primary completion
- Oct 2027 (estimated)
- Study completion
- Apr 2028 (estimated)
- First posted
- 29 Jan 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 will determine the effects of consuming whole fruit on blood sugar control, liver fat, and cardiovascular health in adults with type 2 diabetes who are not treated with insulin.
Detailed description
Diabetes is one of the top three drivers of healthcare costs in the U.S., and nearly half of Americans will develop either diabetes or prediabetes in their lifetime. It is therefore critical to find new strategies to treat or reverse diabetes.
One such approach is adopting a healthy diet, which can dramatically improve blood sugar levels in adults with type 2 diabetes and even induce diabetes remission in some patients. Despite this, not much is known about which food groups are most effective at improving blood sugar levels in patients with diabetes.
Although individuals with type 2 diabetes are often advised to reduce carbohydrate intake, current dietary guidelines also recommend consuming fruit and other carbohydrate-rich foods. This has led to confusion among patients and clinicians about whether eating fruit, particularly in larger amounts, is beneficial or harmful for blood sugar and overall health. Whole fruit differs from many other carbohydrate sources in that whole fruit is rich in fiber, vitamins, minerals, and bioactive plant compounds, while being relatively low in energy density.
Most prior research examining the effects of whole fruit in people with type 2 diabetes has been epidemiologic, focused on individual fruits, or combined whole fruit with fruit juice and/or vegetables into a single food category. As a result, it is unknown how whole fruit, as a food category, affects glycemic control and cardiovascular health.
The investigators previously found that a whole-fruit-rich, Mediterranean-style diet improved blood sugar control and blood pressure in patients with type 2 diabetes and even allowed some patients to wean off all anti-hyperglycemic medications. The investigators will conduct a follow-up study to determine the effects of whole fruit alone on glycemic control, liver fat, and cardiovascular risk factors. The study will be a single-arm controlled feeding study to determine the effects of eating a large amount of whole fruit for 17 weeks on glycemic control (Aim 1), liver fat (Aim 2a), and cardiovascular disease risk factors (Aim 2b) in patients with insulin-independent type 2 diabetes. The primary measures of glycemic control will be mean 24-hour glucose levels (as measured by continuous glucose monitoring) and mean 3-hour glucose levels (as measured during a 3-hour oral glucose tolerance test). These assessments will be supplemented by, and interpreted in light of, other glycemic outcomes, which are listed as outcomes #3-9 below.
By providing controlled, high-quality evidence, this study will determine whether whole fruit is good or bad for patients with type 2 diabetes and will improve dietary guidelines for the hundreds of millions of individuals with type 2 diabetes.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Whole Fruit | Experimental | Other: Whole FruitParticipants will consume a large amount of whole fruit, constituting 50% of total calories. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Aged ≥18 years
- Diagnosed with type 2 diabetes
- HbA1c between 6.5-12.0%
- Fasting C-peptide level ≥0.5 ng/ml, indicating the patient does not have beta-cell failure, as measured at screening
Key exclusion criteria (16 listed)
- On insulin
- Evidence of latent autoimmune diabetes (LADA) or maturity-onset diabetes of the young (MODY)
- Estimated glomerular filtration rate (eGFR) <45 ml/min per 1.73 m²
- Heart attack in the past 6 months or severe/unstable heart failure
- On weight loss medication, including GLP-1 receptor agonists (e.g., semaglutide, dulaglutide)
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 |
|---|---|---|
| Whole FruitParticipants will consume a large amount of whole fruit for 17 weeks. During the first 6.5 weeks, participants will gradually increase the amount of whole fruit they eat by 5% every 5 days. Once they reach 50% of their calories as whole fruit, they will continue to eat 50% fruit for the remaining 10.5 weeks of the study. This is a controlled feeding study, so participants will consume fruit prepared in a metabolic kitchen. The fruit will consist of fresh fruit, dried fruit, and frozen fruit blended into smoothies. To demonstrate compliance, participants will video-record themselves eating the provided fruit. All participants will receive the same dietary intervention. Participants will otherwise continue their usual diet and lifestyle habits. | Other | Whole Fruit |
Primary outcome
Mean 24-hour Glucose Levels
Time frame: Change from baseline to week 17
Average 24-hour interstitial glucose levels (mg/dl), as measured by continuous glucose monitoring (CGM). If needed, data will be adjusted for any changes in antihyperglycemic medication use, using the medication effect score (MES).
Mean 3-hour Glucose Levels
Time frame: Change from baseline to week 17
Mean glucose (mg/dl) during a 3-hour oral glucose tolerance test (OGTT)
Mean 3-hour Insulin
Time frame: Change from baseline to week 17
Mean insulin (mU/l) during a 3-hour OGTT
Mean 3-hour C-Peptide
Time frame: Change from baseline to week 17
Mean C-Peptide (ng/ml) during a 3-hour OGTT
Insulin Sensitivity
Time frame: Change from baseline to week 17
Insulin sensitivity (dl/kg/min/μU/ml) during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model
Dynamic Beta-Cell Responsivity
Time frame: Change from baseline to week 17
Phi_dynamic during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model (which is a set of 5 coupled differential equations; see reference under Citations). Phi_dynamic is a measure of beta-cell responsiveness during first-phase insulin secretion. It is a dimensionless index (arbitrary units), where higher values denote greater insulin secretion
Static Beta-Cell Responsivity
Time frame: Change from baseline to week 17
Phi_static during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model (which is a set of 5 coupled differential equations; see reference under Citations). Phi_static is a measure of beta-cell responsiveness during second-phase insulin secretion. The units of measure are min^-1, and higher values denote greater insulin secretion.
Glycemic Variability
Time frame: Change from baseline to week 17
Measures of glucose variability derived from continuous glucose monitoring, including mean amplitude of glycemic excursions and standard deviation (mg/dl).
Time-in-range Metrics from CGM
Time frame: Change from baseline to week 17
Standard time-in-range metrics, including time-below-range (TBR), time-in-range (TIR), and time-above-range (TAR), as standardized by the International Consensus on Time in Range. Values will be reported as percentages of the 24-hour day.
5 secondary outcomes
Intrahepatic Lipid (Liver Fat)
Time frame: Change from baseline to week 17
Body Weight
Time frame: Change from baseline to week 17
Systolic and Diastolic Blood Pressure
Time frame: Change from baseline to week 17
Heart Rate
Time frame: Change from baseline to week 17
Lipids
Time frame: Change from baseline to week 17
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 7 Jul 2026.
- Background: PubMed 24651807Cobelli C, Dalla Man C, Toffolo G, Basu R, Vella A, Rizza R. The oral minimal model method. Diabetes. 2014 Apr;63(4):1203-13. doi: 10.2337/db13-1198.
- 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.
Courtney M Peterson principal investigator
Harvard School of Public Health (HSPH)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Whole Fruit in people with Type 2 Diabetes, run by Harvard School of Public Health (HSPH) at 1 site in United States.
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 4 inclusion and 16 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 7 Jul 2026. 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 States. 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?
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?
Contact Kathleen Johnson Research Project Manager, MPH, RD (617-998-6333, fruit2@hsph.harvard.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean 24-hour Glucose Levels (time frame: Change from baseline to week 17). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07376226, which also lists 1 linked publication.
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 7 Jul 2026.