Medical practice

Swallowable gastric balloon could help with weight loss

"Swallowable gastric balloon could help the obese lose weight without surgery," The Guardian reports. The news, which was widely reported, is based on a study presented at the European Congress of Obesity in Portugal.

Researchers in Italy found obese patients who used a swallowable gastric balloon lost on average about 15kg over a four-month period.

Gastric balloon treatment for obesity involves inserting a balloon in the stomach and filling it with air or liquid. This means you can't or won't need to eat as much to feel full.

Currently, deflated gastric balloons usually have to be inserted – and later removed – in a hospital setting. This involves being sedated or having a general anaesthetic and having an endoscopy, where a thin tube with a camera and light is passed down your throat.

The swallowable gastric balloon used in this study can be inserted without any invasive procedures such as endoscopy. The balloon is swallowed by the patient and then filled with liquid once it's in the stomach. The balloon stays in the stomach for four months, until it automatically deflates and is excreted.

Overall, the study found the swallowable gastric balloon was a safe procedure that led to weight loss in obese patients, when used alongside a low calorie diet. However, the rate of weight loss slowed down after 12 weeks of treatment, until the introduction of a very low calorie diet.

This is early stage research involving a small number of patients who were followed up for just 16 weeks. Long-term studies are needed to see if the swallowable gastric balloon can help people not only lose weight but also keep the weight off.

Where did the story come from?

This research was carried out by researchers from Sapienza University in Italy. No external sources of funding were mentioned.

The research was presented as a conference poster at the 24th European Congress on Obesity taking place in Portugal from May 17-20 2017. The poster is also available online (PDF, 530kb).

The media coverage around this research was generally accurate, though several reports made no mention of the fact that any weight loss achieved may not last beyond the period when the gastric balloon is in place, unless patients make long-term changes to their diet.

What kind of research was this?

This prospective non-randomised study investigated whether treatment with a swallowable gastric balloon is a safe and effective option to help obese people lose weight.

Used alongside a low calorie diet, the balloon can make it easier to adhere to the strict intake of the diet because it makes you feel fuller.

Non-randomised prospective studies like this one are useful to follow up on medical interventions, and assess their safety and effectiveness by looking at the number of adverse events. However, the best way to validate these findings would be by using a randomised controlled trial (RCT).

What did the research involve?

Researchers studied 38 obese patients (28 men and 10 women) for 16 weeks after insertion of the gastric balloon.

The mean age of the participants was 46, their mean initial weight was 110kg, and they had a mean BMI of 39.

The people recruited for the study had struggled to lose weight through dieting alone, and had refused other treatments involving gastric balloons because of the need for sedation and endoscopy.

The participants were asked to swallow the gastric balloon, which is packaged inside a capsule the size of a pill and attached to a thin tube. The capsule disintegrates when it's in the stomach, and the balloon is then filled with 550ml of liquid.

The thin tube is then detached and the gastric balloon remains in the stomach. After four months, the release valve in the balloon opens automatically, which empties the fluid, and the balloon is then excreted.

For the first 12 weeks of treatment, the patients were given a low calorie diet, which was then switched to a very low calorie ketogenic diet (~700 kcal/day) for the last four weeks.

Follow-up took place every two weeks. At the end of the 16 weeks, the balloon was excreted and participants were asked to follow a Mediterranean diet to maintain their weight loss.

What were the basic results?

Overall, treatment with the gastric balloon was well received by all the patients involved in the study. In all cases, the balloons were swallowed, filled and excreted successfully.

There were no reports of serious adverse events. Side effects such as nausea, vomiting and abdominal pain resolved on their own or with medication.

The participants lost weight throughout the 16 weeks of gastric balloon therapy:

  • at week 4: the mean weight loss was 5.4kg
  • at week 8: mean weight loss 8.9kg
  • at week 12: mean weight loss 11.5kg
  • at week 16: mean weight loss 15.2kg

Although weight loss decreased overall in the first 12 weeks, the rate of weight loss began to slow down at the end of the first 12 weeks. It then increased again in the last month, when the patients followed a very low calorie ketogenic diet (VLCKD) to boost weight loss.

How did the researchers interpret the results?

The researchers concluded: "The Elipse balloon appears to be a safe and effective weight loss method. Furthermore, the introduction of a VLCKD (very low calorie ketogenic diet) improves weight loss."

They added: "The procedureless nature of the Elipse balloon may make it amenable to a larger population of obese patients not responding to diet treatment and a variety of clinicians (e.g. nutritionists, dieticians and internists) who currently do not have access to endoscopic or surgical weight loss devices."


This research investigated whether treatment with a swallowable gastric balloon is a safe and effective option to help obese people lose weight.

Overall, the study found the gastric balloon led to weight loss when used alongside a low calorie diet, with a mean weight loss of 15.2kg by the end of the 16-week treatment period.

However, the rate of weight loss declined after 12 weeks of treatment, before going up again in the last month with the introduction of a very low calorie diet.

This is an interesting piece of research, but it has a number of limitations.

  • This is a very small study, and the findings would have to be observed on a large scale before it can be decided whether this swallowable gastric balloon is a safe and cost-effective option compared with other gastric balloon procedures.
  • The study only looks at the effects of the gastric balloon after 16 weeks of treatment. The effects of the gastric balloon for long-term weight loss would have to be studied before it's decided whether this could be a sustainable weight loss treatment.
  • Because the study has only been presented as a poster at a conference, only limited information on the findings is currently available. A full research paper would provide more information on the methods and limitations of the study. 

Dr Simon Cork, Research Fellow at the Department of Investigative Medicine at Imperial College London, commented: "This is an interesting study with interesting outcomes for clinical practice. It is a small study (only 38 people); however, in terms of proof of concept this is acceptable.

"It is also noteworthy that weight loss begins to slow down as the trial goes on (until the introduction of a low calorie diet). This is not surprising, but shows that in itself, gastric balloons are not long-term solutions for weight loss.

"Sadly, the weight lost through this balloon will undoubtedly be put back on soon after the balloon is removed. Nevertheless, gastric balloons are still useful for some patients, and the introduction of a device which doesn't require surgery to implant is a positive step forward."

Read more on weight loss and weight loss surgery.

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