for people ages 35 years and up (full criteria)
at Irvine, California and other locations
study started
estimated completion
Principal Investigator
by Andrew Odegaard



Diet beverages sweetened with artificial sweeteners occupy a unique category in the food environment as they are a source of intensely sweet taste with no calories. Diet beverages are the single largest contributor to artificial sweetener intake in the U.S. diet, and people with diabetes are the highest consumers of diet beverages, tending to consume them as a replacement for dietary sources of sugar, especially in place of sugar-sweetened beverages. This behavior has been endorsed by dietetic and scientific organizations, and diet beverages are marketed as being synonymous with better health, suitable for weight loss, and thus advantageous for diabetes control. The underlying public health concern is that there are few data to support or refute the benefit or harm of habitual diet beverage consumption by people with diabetes; therefore randomized trials with relevant outcomes must be conducted because they would address many limitations of previous research and have major implications for dietary recommendations on diet beverage intake and primary and secondary prevention of chronic disease. To begin addressing this important scientific gap the investigators are testing the effect of diet beverage intake on diabetes control parameters in free-living adults with type 2 diabetes in a randomized, two arm parallel trial with a run-in period of 2-weeks and an active intervention period of 24-weeks. This study will recruit 200 patients with type 2 diabetes who are usual consumers of commercial diet beverages and randomize them to receive and consume either: 1) A commercial diet beverage of choice (3 servings or 24 oz. daily); or 2) Unflavored bottled water of choice (sparkling or plain) (3 servings or 24 oz. daily). The primary outcome will be a central measure of clinical diabetes control in glycated hemoglobin (HbA1c). The study will also measure the nature and magnitude of glycemic excursions via continuous glucose monitors, as well as clinical markers of cardiometabolic risk and kidney function. Lastly, investigators will measure plausible mechanisms whereby diet beverage intake may alter risk by assessing the effect of diet beverage intake on the functional composition of the gut microbiome via stool samples and comprehensive metabolomics, satiety hormones, as well as usual dietary intake, and upstream behavioral pathways which may inform dietary intake patterns.

Official Title

Effect of Artificially Sweetened Beverages on Diabetes Control in Adults With Type 2 Diabetes


Type 2 Diabetes, Diet beverages, diet, diabetes control, artificial sweeteners, continuous glucose monitor, gut microbiome, metabolomics, Diabetes Mellitus, Type 2 Diabetes Mellitus, Diet Beverage, Water


You can join if…

Open to people ages 35 years and up

We will include men, women and non-binary participants with T2D, age 35 years and older, able to provide informed consent, otherwise healthy, who meet the following criteria:

- Physician diagnosed type 2 diabetes ≥ 6 months prior to screening - HbA1c 6.5-8.5% at participant screening - Current treatment with lifestyle changes or stable diabetes-related medication levels for the past 3 months - Willingness to provide consent to contact treating physician and physician agreement to refrain from changing diabetes-related medications during the trial (change defined as > 2 fold change in dose of any 1 hyperglycemic agent or addition or subtraction of an agent) - No physician-directed medication change for 3 months if prescribed medication for lipids or blood pressure - Usual consumers of diet beverages (≥ 3 servings/ week (24 oz.) and the willingness to maintain fidelity of the intervention, and participate in all aspects of the intervention - Not actively looking to make major lifestyle alterations during the study period with stable weight for 2 months (within 3%).

You CAN'T join if...

  • Type 1 diabetes or suspected type 1 diabetes (lean with polyuria, polydipsia, and weight loss with little response to metformin)
  • "Secondary" diabetes due to specific causes (e.g. monogenic syndromes, pancreatic surgery, and pancreatitis)
  • Diabetic Ketoacidosis hospitalization within last 6 months
  • Severe/major hypoglycemia in the last 3 months-severe/major hypoglycemia is defined as a hypoglycemic event in which patient requires assistance of another person to manage the episode
  • Glucocorticoid use (prednisone 2.5 mg/d or more or its equivalent)
  • History of intolerance or allergy to diet beverages or AS or phenylketonuria
  • Any condition that is known to affect the validity of the glycemic measures (Hba1c)
  • Major cardiovascular disease event or surgery within past 6 months
  • Gastrointestinal disease
  • Renal or liver disease
  • Current treatment for cancer
  • Those with major surgery planned or history of bariatric surgery
  • Antibiotic treatment (> 6 days) within past 6 months
  • Currently pregnant (via self-report) or planning to become pregnant during study period; <1 year postpartum and breast feeding
  • Current participation in another interventional clinical trial
  • Previous randomization in this study,
  • Heavy alcohol consumption (on average >2 drinks/day for women and >3 drinks/day for men)
  • Habitual consumer of SSB ≥ 1 serving / day (8 oz.)
  • Does not drink diet beverages
  • BMI < 20.0 kg/m2


  • University of California, Irvine
    Irvine California 92697 United States
  • University of Minnesota
    Minneapolis Minnesota 55454 United States

Lead Scientist at UC Irvine


in progress, not accepting new patients
Start Date
Completion Date
University of California, Irvine
Study Type
Expecting 181 study participants
Last Updated