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Gastric Bypass vs. Diet for Type 2 Diabetes (RBD-T2D Trial)

Waitlist Available
Led By Samuel Klein, MD
Research Sponsored by Washington University School of Medicine
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Type 2 Diabetes
For Low-Calorie Diet group: BMI 34-55 kg/m², Type 2 Diabetes and Non-Diabetics, Signed informed consent
Screening 3 weeks
Treatment Varies
Follow Up 6 months (before and after targeted weight loss)
Awards & highlights


This trial will compare the effects of weight loss from gastric bypass surgery to weight loss from a low calorie diet on insulin sensitivity, beta-cell function, and 24-hour metabolic homeostasis in obese subjects with or without type 2 diabetes.

Who is the study for?
This trial is for obese individuals with or without Type 2 Diabetes, having a BMI between 34-55 kg/m². They must not use tobacco, be pregnant/breastfeeding, have had previous intestinal surgery, significant organ dysfunction (other than diabetes), or take meds affecting metabolism. Exercise should be less than 90 minutes per week.Check my eligibility
What is being tested?
The study compares the effects of Roux-en-Y Gastric bypass (RYGB) surgery and a low-calorie diet on weight loss and metabolic health in obese patients. It looks at how each method affects insulin sensitivity in the liver and muscles, beta-cell function, and overall metabolic balance over a day.See study design
What are the potential side effects?
Potential side effects from RYGB may include nutritional deficiencies, digestive issues like nausea or vomiting, surgical complications such as infections or hernias. The low-calorie diet might lead to fatigue, hunger pangs, mood swings and could potentially cause gallstones if weight loss is rapid.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
I have Type 2 Diabetes.
I have a BMI between 34-55, may or may not have Type 2 Diabetes, and agree to participate.
I am scheduled for weight loss surgery.


Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~6 months (before and after targeted weight loss)
This trial's timeline: 3 weeks for screening, Varies for treatment, and 6 months (before and after targeted weight loss) for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.
Primary outcome measures
Changes in hepatic insulin sensitivity
Secondary outcome measures
Changes in 24-hour plasma free fatty acid profile
Changes in 24-hour plasma glucose profile
Changes in 24-hour plasma insulin profile
+7 more

Trial Design

2Treatment groups
Experimental Treatment
Active Control
Group I: Roux-en-Y gastric bypass (RYGB)Experimental Treatment1 Intervention
Subjects in this group are scheduled to undergo roux-en-Y gastric bypass surgery to obtain approximately 16-18% (with a range of 16-25%) weight loss.
Group II: Low-calorie dietActive Control1 Intervention
Subjects in this group will participate in a low-calorie diet intervention to obtain approximately 16-18% (with a range of 16-25%) weight loss.
First Studied
Drug Approval Stage
How many patients have taken this drug
Roux-en-Y gastric bypass surgery

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
Common treatments for Type 2 Diabetes include pharmacological therapies like GLP-1 receptor agonists, lifestyle interventions such as low-calorie diets, and surgical options like Roux-en-Y Gastric Bypass (RYGB). GLP-1 receptor agonists improve glucose control, promote weight loss, and reduce food intake by slowing gastric emptying and acting on the central nervous system. Low-calorie diets induce weight loss by reducing caloric intake, which improves insulin sensitivity and glycemic control. RYGB surgery alters the digestive system to reduce food intake and absorption, leading to significant weight loss and improved glucose homeostasis. These mechanisms are crucial for T2DM patients as they address both hyperglycemia and obesity, which are central to the disease's progression and complications.
Revisiting the concept of incretin and enteroendocrine L-cells as type 2 diabetes mellitus treatment.The Impact of Bariatric Surgery on Type 2 Diabetes Mellitus and the Management of Hypoglycemic Events.Gut hormones and the brain.

Find a Location

Who is running the clinical trial?

Washington University School of MedicineLead Sponsor
1,949 Previous Clinical Trials
2,307,488 Total Patients Enrolled
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)NIH
2,381 Previous Clinical Trials
4,315,032 Total Patients Enrolled
Samuel Klein, MDPrincipal InvestigatorWashington University School of Medicine
27 Previous Clinical Trials
2,151 Total Patients Enrolled

Media Library

Low-calorie diet Clinical Trial Eligibility Overview. Trial Name: NCT02207777 — N/A
Type 2 Diabetes Research Study Groups: Low-calorie diet, Roux-en-Y gastric bypass (RYGB)
Type 2 Diabetes Clinical Trial 2023: Low-calorie diet Highlights & Side Effects. Trial Name: NCT02207777 — N/A
Low-calorie diet 2023 Treatment Timeline for Medical Study. Trial Name: NCT02207777 — N/A
~4 spots leftby Apr 2025