Effect of Whole Fruit on Glycemic Control in Adults With Type 2 Diabetes

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 that comprise the Mediterranean diet, 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 induce diabetes remission and can improve blood sugar, liver fat, and cardiovascular health in adults with type 2 diabetes. Thereafter, participants will be followed for up to one year. As a secondary aim, this study will also test whether consuming a large amount of fructose in whole food form negatively affects liver fat and cardiovascular health.

Pre-registration notes: The primary endpoint is glycemic control, which will be analyzed hierarchically in descending order of importance as:

1. Diabetes remission rate (endpoint #1)
2. Medication effect score (endpoint #2)
3. Fasting glucose and HbA1c (endpoints #3-4)
4. Oral glucose tolerance test and continuous glucose monitoring measures (endpoints #5-14)

while the secondary endpoints (endpoints #15-20) will all be evaluated with equal importance.

Eligibility Criteria:
Inclusion Criteria:

* 20-65 years old
* BMI between 27.0-45.0 kg/m\^2
* First diagnosed with type 2 diabetes within the past 6 years
* HbA1c between 6.0-9.5%%

Exclusion Criteria:

* On insulin
* Diagnosis of diabetes before age 18
* Estimated glomerular filtration rate \< 45 ml/min per 1.732 m\^2
* Heart attack in the past 6 months or severe or unstable heart failure
* On weight loss medication
* Change in the dosage of a chronic medication that may affect study endpoints within the past 3 months
* 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 safety or data validity
* Evidence of cancer (other than non-melanoma skin cancer) within the last 5 years
* Lost or gained more than 5 kg of weight in the past 6 months
* Pregnant, planning to become pregnant in the next 12 months, or breastfeeding
* Major psychiatric condition that would affect the ability to participate in the study
* Not able to eat the provided study meals
* Behavioral factors or circumstances that may impede adhering to the dietary intervention
* Not able to do the MRI/MRS abdominal scan, such as due to claustrophobia, implanted metal objects, or a body girth of 60 cm or greater