March 10, 2026
At Mayo Clinic, endoscopic sleeve gastroplasty (ESG) is an effective endoscopic therapy for patients seeking nonsurgical treatment for obesity. ESG is a proven, Food and Drug Administration-authorized endoscopic suturing procedure that reduces stomach volume and improves satiety to promote safe and durable weight loss. However, it does not engage the hormonal pathways of appetite control. One potent hunger hormone, ghrelin, is made in the inner surface lining of the top part of the stomach, called the fundus. Targeting the fundus presented an opportunity to make traditional ESG even more effective for weight loss and preventing postoperative weight regain.
To address this mechanistic gap, gastroenterologists and researchers, including those at Mayo Clinic, developed gastric fundal mucosal ablation (GFMA), a novel, minimally invasive procedure that uses thermal energy to treat the fundus lining. Early clinical evidence suggests that combining GFMA with ESG may yield weight-loss outcomes approaching those of gastric sleeve surgery but without incisions, anatomical resection or long-term vitamin supplementation.
"Bariatric surgery is still king for treating obesity, but because of the increased invasiveness and perception of risk, its uptake is really limited — maybe 1% to 2% of eligible candidates end up pursuing it," says Daniel B. Maselli, M.D., a gastroenterologist at Mayo Clinic in Rochester, Minnesota, where he co-leads the Metabolic and Bariatric Endoscopy Program with Eric J. Vargas Valls, M.D., M.S. GFMA, particularly when combined with ESG, represents the next-generation approach to endobariatric care.
Innovation in ablation therapy
GFMA uses a lift-then-ablate technique pioneered by Vivek Kumbhari, M.B., Ch.B., Ph.D., an interventional endoscopist and chair of Gastroenterology and Hepatology at Mayo Clinic in Jacksonville, Florida. "Unlike the rest of the stomach, which is thick and muscular, the fundus is very thin — 2 to 3 millimeters in width — so if we suture up into that area, it's inviting disaster," Dr. Maselli says. "One of the appealing aspects of bariatric endoscopy compared to bariatric surgery is that it is less invasive, so safety for any new endoscopic approach has to be a priority." Drs. Maselli and Kumbhari are members of an international expert committee that submitted a safety framework for gastric mucosal ablation for publication.
Directly ablating tissue of this caliber poses a significant risk of deep ulceration or stomach perforation. To mitigate this, before ablating the fundus, bariatric endoscopists at Mayo Clinic instill a cushion of fluid into the layer just beneath the surfacing lining of the fundus, called the submucosa. This creates a physical barrier and heat sink that allows safe treatment of the fundus lining while protecting deeper tissue areas from thermal injury.
"Providing world-class care at Mayo Clinic means presenting patients with options that fit their personal goals, medical needs and risk tolerance. We're proud to do so with GFMA-ESG."
Dr. Kumbhari validated this approach in both animal models and ex vivo human tissue. This preclinical research enabled two in-human trials, called the ABLATE Weight studies, in which 20 adults underwent GFMA without serious adverse events. "All of the adverse events that occurred were predictable and minor gastrointestinal symptoms of recovery — nothing related to perforations, bleeding or ulcers," Dr. Maselli says.
Mayo Clinic bariatric endoscopists perform GFMA and ESG in a single outpatient session. Patients recover at home with about three to five days of gastrointestinal symptoms and are typically back to work in three to four days. The combined procedure takes approximately 90 minutes, whereas ESG alone takes roughly 60 minutes. While ESG is FDA-authorized, GFMA-ESG is still investigational and should be performed only in expert centers.
Early clinical benefits of gastric fundal mucosal ablation and combination procedures
According to a study published in Gastroenterology by Dr. Maselli and colleagues, 10 patients with obesity who underwent GFMA alone experienced a 45% reduction in the hunger hormone ghrelin, 42% reduction in the size of a meal needed to feel completely full and a 7.7% loss of body weight at six months.
The research team also evaluated whether performing GFMA and ESG as a single-stage procedure would confer additional weight-loss benefit. The combination approach yielded a 23.5% total body weight loss. "It's not quite there, but we're definitely within striking distance of a sleeve gastrectomy," Dr. Maselli says. A study in Obesity Surgery reports that sleeve gastrectomy achieves a total body weight loss of 29% at 24 months.
Candidates for single-stage gastric fundal mucosal ablation and endoscopic sleeve gastroplasty
A single-stage GFMA-ESG procedure may be best suited for patients whose weight-loss goals exceed the 15% to 20% typically achieved with ESG alone. GFMA may also benefit patients whose prior weight loss — whether through ESG, GLP-1 medications or lifestyle modification — has been undermined by increased hunger as they lose weight.
The procedure may also appeal to patients who are not candidates for or wary of committing to long-term GLP-1 receptor agonist medications. It can also be a reliable tool for patients frustrated by the ever-changing landscape of access and coverage for GLP-1 receptor agonists and similar obesity medications. "Once you have the GFMA-ESG procedure, you've had it. And unlike medications, no one is going to take that away from you or change your insurance coverage so that you lose your hard-earned progress," Dr. Maselli says.
As the field of metabolic and bariatric endoscopy evolves, combination procedures that target multiple pathways of appetite and metabolism help close the gap between costly, higher risk operations and lifelong medication management. "The goal is to provide patients with meaningful tools that exist within the multidisciplinary framework for obesity," Dr. Maselli says. "Providing world-class care at Mayo Clinic means presenting patients with options that fit their personal goals, medical needs and risk tolerance. We're proud to do so with GFMA-ESG."
For more information
Maselli DB, et al. Endoscopic gastric fundal mucosal ablation induces weight loss in adults with obesity. Gastroenterology. 2024;167:1457.
Abedalqader T, et al. Comprehensive long-term outcomes and durability of sleeve gastrectomy with up to 14 years of follow-up. Obesity Surgery. 2026;36:439.
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