Bariatric Surgery vs Diet for Weight Loss

Overseen By Andres J Acosta, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Mayo Clinic

Must not be taking: Orlistat, Phentermine

Disqualifiers: Abdominal surgery, Chronic GI diseases, Psychiatric dysfunction, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

Duration: 12 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how the bile acid pathway, which aids in fat digestion, responds to weight loss from either Roux-En-Y Gastric Bypass (RYGB) surgery or a low-calorie diet. The researchers aim to determine if the method of weight loss affects this pathway differently. Participants will either undergo RYGB surgery or follow a diet plan designed by a dietitian. Suitable candidates have a BMI of 40 or higher and are generally healthy, with any existing health conditions well-controlled.

As an unphased study, this trial provides participants a unique opportunity to contribute to understanding the effects of weight loss on digestion.

Will I have to stop taking my current medications?

Participants must avoid taking any new over-the-counter or prescription medications or herbal supplements that have not been reviewed and approved by the physician or study coordinator. The protocol does not specify if you need to stop your current medications, but you should discuss them with the study team.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that Roux-En-Y Gastric Bypass (RYGB) surgery is generally well-tolerated by many patients. Studies have found that patients often lose significant weight and see improvements in conditions like type 2 diabetes and high blood pressure. However, like any surgery, it carries risks. Some people may experience issues such as infections or nutrient deficiencies after the procedure.

In contrast, low-calorie diets are usually safe for most people. They promote weight loss without surgical risks. However, some individuals might struggle to maintain a low-calorie diet, which can lead to regaining weight.

Both treatments have their advantages and disadvantages. Consulting healthcare providers is crucial to determine which option is safest and most effective for individual needs. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about comparing Roux-En-Y Gastric Bypass (RYGB) and a low-calorie diet for weight loss because these approaches offer distinct pathways to tackle obesity. Unlike standard treatments that often involve medication or lifestyle changes alone, RYGB is a surgical procedure that alters the digestive system to limit food intake and nutrient absorption, potentially leading to significant and sustained weight loss. On the other hand, a low-calorie diet, guided by a registered dietitian, emphasizes sustainable lifestyle modifications without surgery, focusing on reducing calorie intake to promote gradual weight loss. This trial aims to reveal the effectiveness and benefits of each method, providing insights into tailored strategies for weight management.

What evidence suggests that this trial's treatments could be effective for weight loss?

This trial will compare the effectiveness of Roux-En-Y Gastric Bypass (RYGB) with a low-calorie diet for weight loss. Research has shown that RYGB is highly effective for long-term weight loss. Studies have found that about 72% of patients maintained at least a 20% weight loss even after ten years. One study showed that RYGB patients lost about 31.5% of their weight in the first year, and this weight loss remained above 20% in the following years. Additionally, RYGB can help improve conditions like type 2 diabetes. In contrast, a low-calorie diet can also lead to weight loss, but the long-term results are not as strong or consistent as those from RYGB. Participants in this trial will be assigned to either the RYGB surgery arm or the low-calorie diet arm to evaluate these outcomes. ^{2 3 5 6 7}

Who Is on the Research Team?

Andres Acosta

Principal Investigator

Mayo Clinic

Are You a Good Fit for This Trial?

This trial is for adults with severe obesity (BMI ≥ 40) who are healthy or have controlled health issues. Women must not be pregnant. Participants will either undergo Roux-En-Y Gastric Bypass surgery at the Mayo Clinic or follow a low-calorie diet if they're not having surgery. People with untreated psychiatric disorders, alcoholism, eating disorders, certain past surgeries, chronic gastrointestinal diseases, or conditions affecting study participation are excluded.

Inclusion Criteria

Women of childbearing potential will have negative pregnancy tests within 48 hours of enrolment

BMI: ≥ 40

The non-RYGB participants (BMI ≥40) will be otherwise healthy individuals with no unstable psychiatric disease and no unstable cardiac, pulmonary, gastrointestinal, hepatic, renal, hematological, neurological, or endocrine disorders.

Exclusion Criteria

If you have significant mental health issues like anxiety, depression, substance abuse, or eating disorders, you may be excluded from the study. A screening test will be used to check for these issues. If any problems are found, you will be referred to your primary care doctor for further evaluation and care. Additionally, your alcohol consumption will be assessed using a questionnaire. If your score is above the recommended limits, it will be reviewed by the study team to determine if you are eligible for the study.

History of abdominal surgery including cholecystectomy and other than appendectomy, Caesarian section or tubal ligation

Any acute or chronic condition or other disease that, in the opinion of the Investigator, would limit the subject's ability to complete and/or participate in this clinical study.Participant activities: If recruited for the investigation participants will be asked to refrain from donating blood; refrain from participating in other research studies; avoid taking any additional over the counter or prescription medications or herbal supplements that have not been reviewed and approved by the physician or the study coordinator until the study has been completed

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline Testing

Participants undergo baseline testing including stool collection and blood sampling after an overnight fast

1 day

1 visit (in-person)

Treatment

Participants undergo RYGB surgery or follow a low-calorie diet until 7% body weight loss is achieved

12 weeks

Follow-up

Participants are monitored for changes in bile acid excretion and other health metrics

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Low-calorie Diet
• Roux-En-Y Gastric Bypass

Trial Overview The study compares how the bile acid pathway responds to weight loss from two methods: Roux-En-Y Gastric Bypass surgery and a strict low-calorie diet alone. The goal is to see if there's a difference in this metabolic pathway depending on the weight loss strategy used.

How Is the Trial Designed?

Group I: Roux-En-Y Gastric Bypass (RYGB) Active Control 1 Intervention

Participants will have elected to have RYGB surgery per standard of care.

Group II: Low-calorie Diet Active Control 1 Intervention

Participants will have a low-calorie diet prescribed by a registered dietitian.

Who Is Running the Clinical Trial?

Mayo Clinic

Lead Sponsor

Trials

3,427

Recruited

3,221,000+

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Trials

2,513

Recruited

4,366,000+

Published Research Related to This Trial

In a study of 213 type 2 diabetes patients with a BMI of 25 to 32.5 kg/m2, Roux-en-Y gastric bypass (RYGB) was found to be more effective than medical treatment in achieving significant metabolic improvements, with 23.9% of RYGB patients meeting the triple endpoint compared to only 7.0% in the medical group.

However, RYGB was associated with a higher rate of complications (36 vs. 22), highlighting the need to weigh the benefits of improved metabolic outcomes against the risks of surgical complications when considering treatment options for patients with lower BMI.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Two-year outcomes of Roux-en-Y gastric bypass vs medical treatment in type 2 diabetes with a body mass index lower than 32.5 kg/m2: a multicenter propensity score-matched analysis. Ling, J., Tang, H., Meng, H., et al.[2022]

Bariatric surgery, such as Roux-en-Y gastric bypass and biliopancreatic diversion, is effective for long-term weight loss and reducing health risks in morbidly obese individuals, but it can lead to serious nutritional complications that may require revisional surgery.

In a study of four patients who underwent revisional surgery due to complications, one patient died, highlighting that while revision surgery is rare, it carries increased risks and can involve different surgical approaches depending on the patient's condition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Revisional surgery in severe nutritional complications after bariatric surgical procedures: report of four cases from a single institution and review of the literature. Braga, JGR., Concon, MM., Lima, AP., et al.[2021]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40709782/

Evaluating the Effectiveness and Long-term Outcomes of ... Results: RYGB was associated with more significant long-term weight loss and superior T2DM remission rates. SG had a lower risk of nutritional ...

2. nejm.org nejm.org/doi/full/10.1056/NEJMoa1700459

Weight and Metabolic Outcomes 12 Years after Gastric ... Furthermore, at 10 years, 72% of the patients who had undergone Roux-en-Y gastric bypass had maintained at least a 20% weight loss from baseline ...

3. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/34953743/

10-year weight loss outcomes after Roux-en-Y gastric ... RYGB results in clinically significant and durable weight loss. Attendance at periodic follow-up visits does not appear to be associated with long-term ...

4. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2819400

Ten-Year Outcomes Following Roux-en-Y Gastric Bypass ... Total weight loss was 20.0% (95% CI, 15.3%-24.7%) for RYGB and 33.9% (95% CI, 27.8%-40.0%) for DS (P = .001). Mean serum lipid levels, except ...

5. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0039606024001818

Comprehensive outcomes after Roux-en-Y gastric bypass ... The maximum mean percentage total weight loss achieved at 1 year was 31.5% ± 5.7% and was consistently >20% throughout follow-up. Sustained resolution of ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3819407/

Clinical factors associated with weight loss outcomes after ... Roux-en-Y gastric bypass (RYGB) surgery can induce a substantial weight loss that is associated with improvement in type 2 diabetes, decreased incidence of ...

7. asmbs.org asmbs.org/news_releases/new-study-shows-long-term-effectiveness-of-gastric-bypass-in-treating-type-2-diabetes-and-obesity/

New Study Shows Long-term Effectiveness of Gastric ... Peak weight loss of 31.8% was achieved after 18 months and stabilized at 23% after 10 years and up to the 20-year mark. The overall 15-year ...