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Our gut reaction: claim that magnetic brain stimulation aids weight loss based on shaky foundation

Magnetic brain stimulation causes weight loss by making gut bacteria healthier

Our Review Summary

The focus of this news release from The Endocrine Society is on research examining the impact of deep transcranial magnetic stimulation (dTMS) — a non-invasive treatment that can stimulate different regions of the brain — on weight loss, hormones and signaling molecules that can affect metabolism and appetite, and composition of the gut microbiome in 14 obese human subjects living in Italy. Microbiome refers to the community of microorganisms living in and on our bodies, most of which are within the gut, and their genetic makeup.

The results indicated that volunteers who underwent dTMS lost more weight and fat mass than those who had a sham procedure and that changes were seen in the microbiome profile in individuals who’d had dTMS. The release didn’t discuss any changes in the sham group, and there was no discussion of where these results fit within the total body of evidence in this area of research.

Most importantly, the release takes significant liberties by stating that dTMS can directly impact microbes living in the gut, without considering the impact that weight loss and lifestyle changes have on microbial composition.

Employing a more cautious interpretation of the results, and including a discussion of costs, risks, and comparisons to other weight loss treatments would have significantly improved the release.


Why This Matters

Researchers and clinicians work relentlessly every day to find treatments for obesity and its chronic health consequences, and yet, new, safe and effective techniques are few and far between.

It’s well known that obesity treatment and management are critical concerns in the United States and abroad. Any new technique that might influence weight loss, appetite, or the gut microbiome is exciting to consider, given that lifestyle changes and prescription weight loss drugs often have limited long-term impacts. However, this news release overstates and oversimplifies the results of the study without fully addressing the complex interplay between weight loss, metabolic hormones and neurotransmitters (the brain’s chemical messengers), and the microbes living in our gut. Change in one of these components typically doesn’t proceed without the others, and the mechanisms are extremely intricate and multifaceted.

This release seems to leap from Point A to Point C in a conclusion that does not show appropriate and cautious interpretation of the results of this very small study.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Cost of dTMS is not mentioned in this release. After doing a bit of independent information gathering, it seems that even though dTMS may be more cost-effective than other more invasive neurostimulation techniques, each session can cost a patient roughly $400-$500, according to PyschologyToday. Individuals in this study underwent 15 sessions each, which amounts to $6000 to $7500 for five weeks of therapy. We don’t know the long-term effects of dTMS on weight loss, nor do we know if, or – more likely – how often these sessions would need to be repeated, but it’s easy to see the price for an individual mounting quickly.

The release doesn’t mention insurance coverage but costs for this type of therapy are likely to be out-of-pocket.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

One of the least straightforward ways to present research results is by stating changes in percentages rather than absolute differences between groups — and this release does exactly that. The release states, “After five weeks of treatment, subjects receiving dTMS lost more than 3 percent of their body weight and more than 4 percent of their fat — significantly more than controls did.” And yet, the release doesn’t report actual body weight or body fat data, leaving readers out in the cold as to what a 3 or 4% change in weight or fat loss really means. This is unintentionally misleading for people trying to assess the value of the treatment.

Current guidelines for treating obesity recommend a 5 to 10 percent weight loss within one year for benefits to be clinically meaningful, and it’s uncertain if participants would achieve this goal, given the short time frame of the study. Neither the release or the abstract it’s based on addressed whether volunteers in the sham group (those who didn’t receive dTMS therapy) also lose weight or fat mass. Without this comparison, it’s difficult to understand the impact of dTMS itself or if the placebo effect played a role in these results.

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

Specific risks are not discussed, though it’s mentioned that dTMS is currently approved in the U.S. for treating major depression and is being studied in other countries for treating neuropsychiatric disorders. Unlike deep brain stimulation, this technique does not require an operation or implantation of electrodes, so we can deduce that the potential harms are lower than other neurostimulation procedures. Nevertheless, a brief mention of harms would give readers a sense of the risk-benefit balance should dTMS rise in popularity and availability in the coming years.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release tells us that this research builds upon previous findings demonstrating that dTMS reduced food cravings and induced weight loss in obese individuals. That conclusion is also supported by the results of the current study, though we can’t gloss over the fact that the study only had 14 participants total — just 7 of whom received dTMS.

The release claims that dTMS “helps obese people lose weight, partly by changing the composition of their intestinal bacteria.” But based on the study design of this research, there simply isn’t a way to determine if the changes in gut microbes were due to changes in weight, food intake, physical activity, hormonal or metabolic shifts, or if they were directly due to dTMS. The release suggests that dTMS can influence pituitary hormones and neurotransmitters, which are known to affect appetite and certain microbiota, respectively, but very little is known in this area of research and it would be wise to tread with caution through this conclusion.

Does the news release commit disease-mongering?


The release doesn’t engage in disease mongering. Obesity is an increasing problem on both the individual and population-level scales. The release provides some context about why new obesity treatments are needed, as well as the possible role gut microbes might play in weight management.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

No funding sources or conflicts of interest are described in the news release.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

While many strategies for weight loss are well known to the general public, none are mentioned in this release. It would be beneficial for readers to be able to compare the weight loss and metabolic changes in subjects who underwent dTMS to the results typically seen through changes in diet and physical activity, FDA-approved weight loss medications, or bariatric surgery, all of which are widely accepted treatments for obesity.

Does the news release establish the availability of the treatment/test/product/procedure?

Not Satisfactory

The release does not discuss the availability of this treatment and the treatment does not appear to be available for obesity at this time. Since dTMS is only approved in the U.S. for treatment of depression, it’s unlikely that it would be available to people without a formal diagnosis of depression.

Does the news release establish the true novelty of the approach?


The news release confirms that dTMS has been around for a while and is used to treat other conditions, but highlights that using the procedure to treat obesity is a new area of exploration.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?


Though the release does take liberties in stating the conclusion of the study, it stays away from sensational language about the dTMS and its potential role in weight loss and microbial changes.

Total Score: 3 of 10 Satisfactory


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