A Decade of Tech, Part 8

Currently offered for sale (US$4,499.00) is the domain name vBloc.com, ​described as “a perfect fit for your business or personal project.” If, that is, your business or personal project is the manufacture of an appetite suppression gadget suitable for implantation in the body of a severely obese person who within the past five years had tried and failed to shed weight by other methods. Under its formal name, the Maestro Rechargeable System, the device was approved by the Food and Drug Administration in 2015.​ It included some components implanted in the body and others located outside. ​

The internal components include a rechargeable pulse generator (also called a neuroregulator disc) which delivers electrical signals to nerve electrodes. The electrodes are placed on the trunks of the vagus nerve in the abdomen and two electrical leads connect the electrodes to the pulse generator. The external components include a transmit coil, mobile charger, and clinician programmer.​

Installation would involve minimally invasive surgery,​ and the externally-worn battery would be on for up to 12 hours per day, and need a weekly recharge. Its purpose was to block signals along the vagus nerve, telling the brain that the stomach was empty or full, and also to “decrease calorie absorption through lower digestive enzyme secretion.” It was said to allow patients “to address obesity without any restrictions to food intake and any adjustments to their lifestyle.” This is difficult to envision. Could a person really eat unrestrictedly and be okay, as long as they had a gadget? Wouldn’t the presence of an ever-open port necessitate some lifestyle changes?

Aaron Mamiit wrote,​

Functions of the vagus nerve involve the enabling of several mechanisms in the human metabolic and gastrointestinal systems, including stomach expansion, stomach contraction, gastric acid release, stomach content release into the small intestine, digestive pancreatic enzyme secretion and the sensations of both hunger and fullness.

Patients who received over 12 daily hours of vBloc therapy “achieved more than 25 percent average excess weight loss over a period of 12 months.” These numerical statements can be tricky. If a person was judged to be 40 pounds too heavy, that would mean they lost maybe 10 pounds over a year, which does not sound so impressive when phrased that way. In 2012 during testing, it was estimated that the system would cost the patient $15,000.

One trial involved 503 Australian and American subjects, of whom 90% were women. ​ The researchers found that clinically significant weight loss…​

[…] was related to hours of device use. Post-study analysis suggested that the system electrical safety checks (low charge delivered via the system for electrical impedance, safety, and diagnostic checks) may have contributed to weight loss in the control group.

They concluded that weight loss was not impressively greater among the participants than in the control subjects. In another trial concerning morbidly obese patients,​ 162 received the working device and 77 were implanted with a fake, and they all had weight management education. The report concluded that:​

[…] the use of vagal nerve block therapy compared with a sham control device did not meet either of the prespecified coprimary efficacy objectives, although weight loss in the vagal block group was statistically greater than in the sham device group.

On the positive, side, the device proved to be safe and well tolerated by the implantees. A couple of years later, vBloc therapy reportedly​ “continues to result in medically meaningful weight loss with a favorable safety profile through 2 years.” In a manufacturer-conducted study, the participants with the working device lost almost 9 pounds more in a year than those in the control group who had sham devices.

Your responses and feedback are welcome!

Source: “vBloc.com,” PerfectDomain.com, 05/07/23
Source: “Enteromedics Maestro Rechargeable System,” RxList.com 10/14/19​
Source: “FDA approved a device that blocks your hunger pangs,” Mashable.com, 01/15/15
Source: “Appetite Pacemaker: Here’s How this Weight Loss Implant Works,” TechTimes.com, 01/15/12
Source: “The EMPOWER study: randomized, prospective, double-blind, multicenter trial of vagal blockade to induce weight loss in morbid obesity,” NIH.gov, November 2012
Source: “Effect of reversible intermittent intra-abdominal vagal nerve blockade on morbid obesity: the ReCharge randomized clinical trial,” NIH.gov, September 2014​
Source: “Two-Year Outcomes of Vagal Nerve Blocking (vBloc) for the Treatment of Obesity in the ReCharge Trial,” NIH.gov, January 2017
Image by Beth Scupham/CC BY 2.0

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OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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