As you may have heard when we reported on it earlier this month, the FDA has cleared a new weight loss pill (it’s a device, not a drug), called Plenity, and the internet had feelings. After reading up on it, we had some questions of our own. As an advocate for healthy lifestyle practices over dieting, we were a little unsure about how healthy this product could be, since most weight-loss pills or devices tend to be problematic, not addressing the basic lifestyle changes (like exercise and cooking and eating more healthy food) that we know actually work.
But we also wanted to keep an open mind. Obesity continues to be a major health problem in the US, and anything that could help solve that deserves considered attention. So we spoke with Harry Leider, MD, the chief medical officer of Gelesis, the company that has invented and is producing Plenity.
Stay up to date on what healthy means now.
Sign up for our daily newsletter for more great articles and delicious, healthy recipes.
Then we spoke with Violeta Popov, MD, PHD, FACG, an expert from the American Gastroenterological Association, a director of bariatric endoscopy at NY VA Harbor Healthcare System, and an assistant professor of medicine at NYU, to help us decipher just how impactful this device is—and to help sort out any potential negative effects to watch out for.
What is Plenity, anyways?
Plenity is a pill that you take, just before eating. But—and this is a little confusing—it’s really not a drug. Instead, the FDA (and Gelesis) define Plenity as a “weight loss device.” This is because, instead of acting on your body’s chemistry—to make you less hungry, or to speed up your metabolism, for instance—it works physically to fill up your stomach, and make less space available to fill with food.
In this way, Plenity works more like a temporary version of gastric bypass or bariatric surgery—in which part of a person’s stomach is closed off, or removed to make the actual stomach space smaller. Those surgeries are expensive and invasive, but they have resulted in drastic weight loss for many people dealing with morbid obesity. They have also resulted in a number of complications for patients, and some long-term studies find that more than half of patients regain the weight, and the health problems, after several years.
There hasn’t been time to study the long term effects of Plenity, of course. But one big difference is it’s the first weight loss device cleared by the FDA that allows people who are only mildly overweight (with a BMI between 25-27) to use it. Leider says this is ground-breaking because 70% of adults in the U.S. are considered overweight or obese, but only two percent are receiving medical treatment.
How Plenity Works
According to Leider, Plenity consists of citric acid and a “super-absorbent hydrolyzed gel made of carboxymethyl cellulose.” For those of us who aren’t scientists, that’s a form of fiber used commercially in some food products like ice cream or yogurt.
When swallowed, the pill releases the gel, which absorbs 100 times its weight in water, causing the stomach—which has, on average, a 1 liter capacity—to lose about 25% of its available volume.
From here, the gel ultimately travels out the same way food does. It stays intact in the small intestine but enzymes and gut bacteria in the large intestine and colon will break it down. Leider explains that, due to the way it breaks down, it won’t cause constipation the way other weight loss aids can.
One of our biggest concerns with Plenity has been how it would impact gut health (which we’re learning is of increasing importance). Leider says Gelesis’ research (in mice) shows the gel actually has a positive impact on gut health and permeability—preventing leaky gut and other negative conditions.The biotech company is planning to experiment further with human subjects.
When we spoke with Popov, an obesity, weight loss, and gut microbiome expert who has no ties to the company, she was more cautious, noting that while ingesting any foreign substance can make it difficult for your body to digest it, Plenity did seems to not have any severe side effects on gut health in previous clinical studies and she agreed it should be, at the least, perfectly safe for your digestive tract. However, she believes those with pre-exisiting gastrointestinal issues should be wary and use under close observation of their medical professional.
A recent clinical study of Plenity, published in the journal Obesity, found six out of 10 participants on Plenity were positive responders—losing 10% of their bodyweight or more in six months. On average, these participants lost 22 pounds and 3.5 inches from their waist. 14 percent of these positive responders lost 30 pounds or more.
However, Popov was surprised that patients who continued to take Plenity after the initial six-month trial didn’t see any further weight loss (but she noted they were able to keep the weight they did lose off). Popov says more research needs to be done on how Plenity affects certain hormones like ghrelin—our hunger hormone—which controls appetite.
Popov says she is also surprised by how small the sample size was for this study. She says most medications seeking to get FDA approval need thousands of patients for their clinical trials. While this is a device not a medication, she believes it should be held to the same standard.
Interested in learning more about losing weight healthfully?
It’s important to note this clinical trial offered nutritional counseling and lifestyle recommendations for participants. Both participants on Plenity and those using a placebo were encouraged to engage in healthier behavior, including participating in regular, moderate physical activity—equivalent to a 30-minute walk each day—and were counseled to help reduce their average daily caloric intake by 300 calories. It’s unclear still how the pill will be used, or whether it will be as effective without these additions.
Final Thoughts from Popov
Popov says her field of work has shown her permanent weight loss is hard to achieve, and even harder to sustain. And she argues that there’s usually more to the equation than simply making lifestyle changes.
“Our ability to gain weight is predetermined by nature,” Popov said. “It’s hard to fight off weight gain with all the food options out there and if you don’t like exercise. It’s simply hard to lose doing it all on your own. Those who are overweight or obese need a long-term plan.”
Popov says overweight and obese patients should be treated like any one with a chronic disease—even if it is managed or subsides, they still need to be treated as they have the condition nonetheless. Even if her patients lose significant amounts of weight, she still advises them to stick to the long-term plan established before the weight loss occurred, because it’s just too easy to gain it back.
Poplov believes Plenity could be an excellent part of a long-term plan for those with BMIs of 25 or higher. If diet and exercise don’t work, this could be a beneficial intermediary before having to resort to an invasive medical procedure or a drug with frightening potential side effects.
“I think [Plenity] is a wonderful thing to have,” Popov said. “It’s easy to use, and increases availability for those who want to jumpstart weight loss in a minimally invasive way.”