An interventional study of High-Fruit Diet in Diabetes Mellitus, Type 2, sponsored by University of Alabama at Birmingham. Completed at 1 site in United States. Open to participants aged 20 Years to 70 Years. Per ClinicalTrials.gov, last updated 2025-06-10.
Sponsored by University of Alabama at Birmingham · Not applicable, Interventional, and Treatment
Diabetes costs the U.S. healthcare system more than any other disease, 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. Despite this, not much is known about which food groups are most effective at improving blood sugar levels in patients with diabetes.
Interestingly, of the various food groups, epidemiologic data suggests that whole fruit may be one of the most efficacious at both preventing type 2 diabetes and improving blood sugar in patients with type 2 diabetes. However, few clinical trials have investigated the effects of whole fruit on blood sugar control. This study will therefore be the first to determine the effects of increasing whole fruit as a food group in type 2 diabetes patients. This supervised controlled feeding trial will test whether consuming a diet rich in whole fruit for 12 weeks can improve glycemic control and cardiometabolic health in weight-stable adults with type 2 diabetes. The primary endpoint is glycemic control. Since changes in medication doses can skew the interpretation of glycemic outcomes, glycemic control will be assessed hierarchically (in descending order of importance) using (a) attainment of nondiabetic glycemia without medications (as a proxy for diabetes remission), (b) medication effect scores, (c) mean glucose during an oral glucose tolerance test, and (d) 24-hour mean glucose from continuous glucose monitoring. As secondary aims, this study will also test whether consuming a large amount of fructose in whole food form affects liver fat, pancreatic fat, and cardiovascular disease risk factors.
10,923 studies on the registry are indexed under Diabetes Mellitus; 1,318 are open to participants now.
This study's enrollment of 34 is below the median of 80 across 8,367 interventional studies indexed under Diabetes Mellitus.
Browse Diabetes Mellitus studies →University of Alabama at Birmingham is the lead sponsor of 1,396 studies on the registry; 284 are open to participants now.
Of its 156 completed or terminated interventional studies of FDA-regulated products, 124 (79%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Whole fruit-rich diet (\~50% of calories from whole fruit)
Behavioral: High-Fruit Diet
In this supervised controlled feeding study, participants will consume a diet rich in whole fruit. During the Ramp-Up Phase (Weeks 1-4), participants will gradually increase the amount of whole fruit they consume, eventually reaching 50% of calories from whole fruit. In the Main Phase (Weeks 5-12), participants will consume a whole fruit-rich, eucaloric diet that provides 50% of calories in the form of whole fruit. The non-fruit portion of the diet will be styled as a Mediterranean Diet. Participants will be required to approximately keep their weight stable throughout the intervention.
Diabetes Remission Rate
Percentage of patients who can maintain non-diabetic levels 24-hour mean glucose without the aid of pharmacotherapy at week 12
Time frame: Change from baseline to week 12
Medication Effect Score (MES)
% (or percentage). This quantity estimates the percentage by which all anithyperglycemic medications taken by a patient would lower HbA1c levels (i.e., percent of glycated hemoglobin molecules). Higher values indicate a higher dose and/or potency of medications.
Time frame: Change from baseline to Week 12
Mean Glucose During a 3-hour Oral Glucose Tolerance Test (OGTT)
mg/dl
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
Mean 24-hour Glucose Levels as Measured by Continuous Glucose Monitoring (CGM), Adjusted for Any Changes in Medication Doses Via the MES
mg/dl
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
Insulin Sensitivity
Insulin sensitivity (dl/kg/min/μU/ml) during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model.
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
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.
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
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.
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
Mean Insulin During a 3-hour OGTT
mU/l
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
Mean C-peptide During a 3-hour OGTT
ng/ml
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints). Change from week 0 to 12 reported.
Mean Amplitude of Glycemic Excursions From CGM
mg/dl
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)"
Fasting Glucose
mg/dl
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
HbA1c
percentage
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Liver Fat (Intrahepatic Lipid)
Percentage as measured using Magnetic Resonance Spectroscopy (MRS) and 3-point M-Dixon Magnetic Resonance Imaging (MRI)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Pancreatic Fat
Percentage as measured using MRS and 3-point M-Dixon MRI methods
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Systolic and Diastolic Blood Pressure
mm Hg
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Heart Rate
beats per minute
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Time-in-range Metrics From CGM
Time during which glucose levels are between 70 and 300 mg/dl
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Lipids
Fasting total cholesterol (mg/dl), LDL cholesterol (mg/dl), HDL cholesterol (mg/dl), and triglycerides (mg/dl)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Body Weight
kg
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints); assessed weekly
Waist Circumference
cm
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Visceral Fat
Visceral fat as measured using MRI (kg)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Subcutaneous Abdominal Fat
Subcutaneous abdominal fat as measured using MRI (kg)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Gut Microbiome Diversity
Diversity metrics (i.e., alpha and beta diversity)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Gut Microbiome Composition
Taxonomic composition and abundances
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Preference and Sensitivity to Sweet Tastes
As measured on a 0-100 mm visual analog scale (VAS), using a Sweetness Taste Test
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Diet Satisfaction
As measured on a 0-100 mm visual analog scale (VAS)
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Habitual Fruit Consumption
As estimated using a series of semi-quantitative food frequency questions from the Diet History Questionnaire
Time frame: Change from baseline to Weeks 4 and 12 and follow-up Months 6, 9, and 12
Food Cravings
As measured on five-point scales by the Food Craving Inventory-II
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Fruit Liking Visual Analog Scales
As measured by VAS on a 0-100 mm scale
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Food Attitudes and Behaviors
As measured by a modified version of the National Cancer Institute (NCI) 2007 Food Attitudes and Behaviors Survey, which covers constructs including attitudes and beliefs, fruit and vegetable consumption, eating behaviors, and food preferences
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
General Health Status
Healthy days (along various dimensions) as measured by the Centers for Disease Control and Prevention's (CDC) Health-Related Qualify of Life questionnaire
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Depression
As measured on a 0-27 point scale by the Patient Health Questionnaire-9
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Mood States
As measured on a 5-point scale by the Profile of Mood States Short-Form
Time frame: Changes from weeks 0 to 12 (primary timepoint) and weeks 0 to 4 and 4 to 12 (secondary timepoints)
Intervention Satisfaction and Feedback
As measured by qualitative exit interview
Time frame: Week 12
| Milestone | High-Fruit Diet |
|---|---|
| Started | 34 |
| Completed | 12 |
| Not completed | 22 |
Percentage of patients who can maintain non-diabetic levels 24-hour mean glucose without the aid of pharmacotherapy at week 12
| Participants | Fruit-Rich Diet |
|---|---|
| % Who Maintained Non-Diabetic Glycemia Without Pharmacotherapy | 3 |
| % Who Weaned Off All Antihyperglycemic Medications | 6 |
% (or percentage). This quantity estimates the percentage by which all anithyperglycemic medications taken by a patient would lower HbA1c levels (i.e., percent of glycated hemoglobin molecules). Higher values indicate a higher dose and/or potency of medications.
| % (see definition under "Description") | Fruit-Rich Diet |
|---|---|
| Medication Effect Score (MES) | -0.5 ± 0.5 |
mg/dl
| mg/dl | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | 11 ± 9 |
| n=4 participants without medication changes | -20 ± 12 |
mg/dl
| mg/dl | Fruit-Rich Diet |
|---|---|
| Main Analysis | -12 ± 7 |
| Post Hoc Analysis Excluding 1 Outlier with Very Low C-peptide Levels | -18 ± 6 |
Insulin sensitivity (dl/kg/min/μU/ml) during a 3-hour OGTT, as measured by the Oral C-Peptide Minimal Model.
| dl/kg/min/μU/ml | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | 1.27 ± 0.99 |
| n=4 participants without medication changes | 3.03 ± 1.61 |
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.
| arbitrary units * 10^9 | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | 135 ± 60 |
| n=4 participants without medication changes | 122 ± 133 |
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.
| 10^9/min | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | -3.0 ± 4.0 |
| n=4 participants without medication changes | 0.9 ± 10.6 |
mU/l
| mU/l | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | -17.1 ± 4.7 |
| n=4 participants without medication changes | -38.1 ± 6.7 |
ng/ml
| ng/ml | High-Fruit Diet |
|---|---|
| All n=10 participants, including those who changed their medication doses | -0.4 ± 0.4 |
| n=4 participants without medication changes | -1.7 ± 0.5 |
mg/dl
Results for this outcome have not been posted.
mg/dl
Results for this outcome have not been posted.
percentage
Results for this outcome have not been posted.
Percentage as measured using Magnetic Resonance Spectroscopy (MRS) and 3-point M-Dixon Magnetic Resonance Imaging (MRI)
Results for this outcome have not been posted.
Percentage as measured using MRS and 3-point M-Dixon MRI methods
Results for this outcome have not been posted.
mm Hg
Results for this outcome have not been posted.
beats per minute
Results for this outcome have not been posted.
Time during which glucose levels are between 70 and 300 mg/dl
Results for this outcome have not been posted.
Fasting total cholesterol (mg/dl), LDL cholesterol (mg/dl), HDL cholesterol (mg/dl), and triglycerides (mg/dl)
Results for this outcome have not been posted.
kg
Results for this outcome have not been posted.
cm
Results for this outcome have not been posted.
Visceral fat as measured using MRI (kg)
Results for this outcome have not been posted.
Subcutaneous abdominal fat as measured using MRI (kg)
Results for this outcome have not been posted.
Diversity metrics (i.e., alpha and beta diversity)
Results for this outcome have not been posted.
Taxonomic composition and abundances
Results for this outcome have not been posted.
As measured on a 0-100 mm visual analog scale (VAS), using a Sweetness Taste Test
Results for this outcome have not been posted.
As measured on a 0-100 mm visual analog scale (VAS)
Results for this outcome have not been posted.
As estimated using a series of semi-quantitative food frequency questions from the Diet History Questionnaire
Results for this outcome have not been posted.
As measured on five-point scales by the Food Craving Inventory-II
Results for this outcome have not been posted.
As measured by VAS on a 0-100 mm scale
Results for this outcome have not been posted.
As measured by a modified version of the National Cancer Institute (NCI) 2007 Food Attitudes and Behaviors Survey, which covers constructs including attitudes and beliefs, fruit and vegetable consumption, eating behaviors, and food preferences
Results for this outcome have not been posted.
Healthy days (along various dimensions) as measured by the Centers for Disease Control and Prevention's (CDC) Health-Related Qualify of Life questionnaire
Results for this outcome have not been posted.
As measured on a 0-27 point scale by the Patient Health Questionnaire-9
Results for this outcome have not been posted.
As measured on a 5-point scale by the Profile of Mood States Short-Form
Results for this outcome have not been posted.
As measured by qualitative exit interview
Results for this outcome have not been posted.
Collected over Adverse events were collected at baseline (~1 week) and during Weeks 1 through 12.. Non-serious events are listed at a 4% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| High-Fruit Diet | 0/34 (0%) | 0/34 (0%) | 18/34 (52.9%) |
| Event | High-Fruit Diet |
|---|---|
| HypoglycemiaMetabolism and nutrition disorders | 18/34 |
| HyperglycemiaMetabolism and nutrition disorders | 15/34 |
| Mild Stomach PainGastrointestinal disorders | 4/34 |
| Mild TremorNervous system disorders | 3/34 |
| NauseaGastrointestinal disorders | 3/34 |
| DizzinessNervous system disorders | 3/34 |
| FatigueGeneral disorders | 2/34 |
| DiarrheaGastrointestinal disorders | 2/34 |
| Peripheral Sensory NeuropathyNervous system disorders | 2/34 |
Results were analyzed only per-protocol, as is the norm for controlled feeding trials. In our study, per-protocol was defined as (a) completing the study with \>=80% adherence and (b) meeting the weight stability criterion. Twelve participants completed the study, and of these, ten also met the weight stability criterion.
| Age, Continuous(years) | High-Fruit Diet |
|---|---|
| Mean | 56 ± 8 |
| Sex: Female, Male(Participants) | High-Fruit Diet |
|---|---|
| Female | 8 |
| Male | 2 |
| Ethnicity (NIH/OMB)(Participants) | High-Fruit Diet |
|---|---|
| Hispanic or Latino | 0 |
| Not Hispanic or Latino | 10 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | High-Fruit Diet |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 5 |
| White | 4 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Region of Enrollment(participants) | High-Fruit Diet |
|---|---|
| United States | 10 |
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University of Alabama at Birmingham