The study, published online in the American Journal of Physiology -- Endocrinology and Metabolism, focuses on a diabetes drug called Symlin. Symlin is a synthetic version of the fullness hormone amylin.
The researchers included Steven Smith, MD, of the Pennington Biomedical Research Center in Baton Rouge, La.
They studied 88 obese men and postmenopausal women. First, participants weighed in and spent four days in a lab. During that time, they ate as much as they wanted of prepared breakfasts, lunches, dinners, and snacks.
On the Menu
Most of the meals served at the lab were healthy and moderate in calories or fat. Menu items included bagels, fruit, and cereal at breakfast; sandwiches and cookies at lunch; a casserole and pudding at dinner; and peanut-butter-and-jelly sandwiches as snacks.
However, one lunch was particularly fatty and sugary, featuring deep-dish pizzas, ice cream, and soft drinks sweetened with high-fructose corn syrup.
Participants ate by themselves so they weren't influenced by what others were eating. The researchers encouraged them to focus on their food and avoid distractions, eating until they were comfortably full.
The researchers also weighed participants' servings and calculated their calorie intake.
Fullness Hormone Shots
During the first two days of the study, all participants got an inactive shot (placebo) 15 minutes before each meal.
After that, the researchers switched some of the participants to Symlin shots on the same dosing schedule.
When participants finished their four days at the lab, they went home with instructions to inject themselves with Symlin or placebo 15 minutes before each meal.
Using handheld electronic devices, participants rated their feelings of fullness, hunger, and nausea. Finally, they returned to the lab at the end of the six-week study for another meal of pizza and ice cream.
Throughout the study, participants didn't know whether they were taking Symlin or the placebo.
During the study, participants in the Symlin group lost 4.5 pounds. Those in the placebo group maintained their weight.
Both groups cut back on their daily calories. However, the Symlin group trimmed more calories and didn't report more hunger than those in the placebo group.
Early in the study, the Symlin patients shaved 990 calories off their daily calorie intake, while the placebo group cut 243 calories out of their daily intake. That gap narrowed somewhat by the end of the study, but the Symlin group still cut more calories than the placebo group.
Compared with the placebo group, the Symlin group was better able to resist the final pizza-and-ice-cream meal at the end of the study than they had been at the study's start.
Mild nausea was a common side effect in both groups, but that didn't explain the Symlin group's weight loss, note the researchers.
One of the researchers, Christian Weyer, MD, is the executive director of clinical research at Amylin Pharmaceuticals, which makes Symlin and funded the study.
The study appears online in the American Journal of Physiology -- Endocrinology and Metabolism.
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