How can a diet pill make you feel full?

The expanding diet pill may become a new tool in the battle of the bulge. See more tips with staying healthy pictures.
The expanding diet pill may become a new tool in the battle of the bulge. See more tips with staying healthy pictures.
Image courtesy Dreamstime

When you were a kid, did you ever throw some pastel-colored pills into the bathtub and watch as they bloomed into dinosaurs and alligators? Those critters actually have something in common with a new diet pill being developed by an Italian research team.

Led by Professor Luigi Ambrosio, researchers at the National Research Council's Institute for Composite and Biomedical Materials in Naples, Italy, have created a diet pill that expands in the patient's stomach to make him feel full. The pill is about the size of a pea or bean, but when taken with two glasses of water, it swells in your stomach. At maximum capacity, so to speak, the pill holds one thousand times its weight (about a liter of water).


The expanding diet pill is seen as an alternative to gastric bypass and other major procedures that attempt to reduce the amount of food you eat. Currently undergoing trials in Italy, the pill may be for sale sometime in 2008. However, there are safety concerns. Diet pills usually carry a potential for abuse, and in this case, abuse could carry potentially serious side effects. Two or more of the pills and a significant amount of water could lead to an immovable blockage in the stomach or even a rupture. Some bloggers have raised the issue of what happens if the pill becomes lodged in someone's throat. The pill will likely be coated so that it will not immediately absorb any nearby moisture. But if the coating dissolves prematurely, it could be quite dangerous. Presumably the trials currently underway will address some of these issues.

In the next section, we'll look at how the expanding diet pill is made.


Hydrogel Compound

Photo courtesy Free Images                                  Contact lenses                                                  use hydrogel technology.
Photo courtesy Free Images Contact lenses use hydrogel technology.

The pill is made from a hydrogel compound. A hydrogel (related to gelatin or food thickeners like agar) is an incredibly absorbent material with a stunning variety of applications. In the case of the diet pill, the hydrogel is safe and eventually passes through the body, though researchers don't currently know how long the pill retains the absorbed water. Still, Professor Ambrosio and his team believe that if a dieter takes the pill with water before a meal, the stomach would be partially filled by the liquid-filled blob and the dieter would eat less before feeling full.

Hydrogels are already used in many fields. Professor Ambrosio and his colleague Luigi Nicolais have discovered that their hydrogel could be used to treat edemas (or spots of excessive accumulation of fluid in the body). Hydrogels already exist in wound dressings, where they help to keep moisture on a wound and to clean away bacteria and dirt.


Farmers and gardeners use hydrogels, too. Many agricultural products use hydrogels to slow down water absorption in soil. These products, when spread across a crop, help to retain water and nutrients. The boost in water retention allows farmers to use less water and to irrigate less frequently.

Hydrogels could potentially be used for time-released watering of plants. Imagine dropping a hydrogel "sack" of water in a pot where it slowly releases its contents before dissolving away.

The list of products using hydrogel technology goes on, and some of them might surprise you. They include:

So the expanding diet pill seems to have some formidable technology behind it. But what about just eating less? And haven't we heard of something like this before? In the next section, we'll answer those questions.


Konjac and Other Expanding Foods

Photo courtesy FDA                                  In 2001, the FDA issued warnings about konjac candy and                                                  many companies voluntarily recalled their konjac candies.
Photo courtesy FDA In 2001, the FDA issued warnings about konjac candy and many companies voluntarily recalled their konjac candies.

We can't judge the pill effectively until it's on the market, but we have seen some of the features of the expanding diet pill before, both in natural foods and other diet pills.

The konjac plant, also known as the konnyaku potato, is used to make konnyaku and other low-calorie health foods in Japan. These foods are often gelatinous or rubbery. In addition to containing very few calories, konnyaku is 97 percent water and 3 percent glucomannan (a dietary fiber that aids in digestion and passes through the body largely undigested).


Like many "superfoods," konjac is seen by some marketers as a potential weight-loss miracle worker. Two popular diet pills, Lipozene and Centrilene, make use of konjac root. Essentially, these medications are just high-fiber pills. If taken properly, they can aid in digestion and have somewhat of a laxative effect. But they're hardly unique. Konjac pills have been around for a long time under many different names.

If not taken with a proper amount of water, konjac products can be a choking hazard. In late 2001, the Food and Drug Administration (FDA) moved to block the import of konjac candy. These gelatinous candies became lodged in the throats of some children, causing them to choke to death. Because of their lumpy form, the candies mold to the shape of the throat and are difficult to dislodge. In 2002, many companies recalled their konjac candies.

Products containing a type of fiber called psyllium husk seed can also cause a choking hazard. Like other types of fiber, psyllium husk seed absorbs water. If cereal containing psyllium husk seed becomes lodged in the throat, it can expand and cause choking. For this reason, products containing psyllium husk seed shouldn't be consumed dry, and children and people with difficulty swallowing should be careful. The FDA recommends that you check product labels for information about choking hazards.

In the end, it's best to approach diet pills of all sorts with skepticism. Expanding diet pills, hydrogel-based, konjac-derived or otherwise, do about as much as drinking more water, eating less and loading up on fiber through natural foods. The Harvard School of Public Health recommends that adults get 20 to 35 grams of fiber per day. A healthy diet of fruits, vegetables, whole grains and nuts should provide you with more than enough fiber. It may help you lose weight, lower your cholesterol, and you'll be lowering your risk of several diseases at the same time.

For more information about dieting, diet pills, and related topics, please check out the links in the next section.


Lots More Information

Related Articles

More Great Links

  • "Agar Agar." Asia Food Glossary. Asia Source.
  • "Fiber." Harvard School of Public Health.
  • "Hydrogel Dressings Are Essential to Proper Wound Care." Medcompare.
  • "New Diet Pill: The Expanding Blob." Diet Blog. new_diet_pill_the_expanding_blob.php
  • "Psyllium." PDR Health. nmdrugprofiles/nutsupdrugs/psy_0214.shtml
  • "Soil Moist - Water Storing Hydrogel Granules." Biconet.
  • "What is Konnyaku?" The Bard of Avon: Shakespeare in Stratford-upon-Avon.
  • Bren, Linda. "Prevent Your Child From Choking." FDA Consumer Magazine. Oct. 2005.
  • Farris, Meg. "Do weight loss pills live up to the hype?" May 17, 2007. kmsb-20070517-wwl-dietpills.7aeca6ec.html
  • Gemeinhart, Richard Allen. "Properties of superporous hydrogels for drug delivery." Purdue e-Pubs. 1999.
  • Martinelli, Nicole. "Jelly in the Belly: A Diet Pill That Expands So You Don't." WIRED. June 8, 2007.
  • Weil, Andrew. "Is Konjac Fiber Good for You?" Weil Lifestyle. Aug. 15, 2003.