A hydrogel pill has been tested on 20 volunteers for its stomach-expanding effects in an effort to make people feel full. According to the Italian researchers, the feeling of being full lasted for several hours. Hydrogel, a substance used to make diapers more absorbent, expands to 1000 times its size when combined with water. Hydrogel is like cellulose, a substance the body can eliminate in 5 or 6 hours.

Scientists say the 500-mg pill should be taken with 2 glasses of water 30 minutes prior to having a meal. Once inside the stomach, the substance will expand to the size of a tennis ball, which will render the feeling of having just finished a plate of spaghetti. One volunteer took the pill at 11 AM and felt full until early evening.

Another trial is underway including 90 overweight volunteers. If the trial is successful, the pill may be on the market by summer 2008, according to the National Research Council, Italy.