Appetite Control Drug
A New Drug For Controlling Appetite?
What is the problem and what is known about it so far?
Obesity affects many Americans and can hurt a person's health by triggering diabetes, causing high blood pressure, and destroying important blood vessels of the heart and kidney through atherosclerosis. It is believed that obesity is responsible for 280,000 U.S. deaths a year and this number is growing. These deaths could be prevented with diet control, but diet control is particularly difficult for some people because they may have too much or too little of certain appetite controlling hormones. Peptide YY (PYY) is one type of such a hormone that the body produces when a person eats. Researchers hope PYY can be used to help obese people lose weight by reducing their appetite.
Why did the researchers do this particular study?
To find out if an injection of PYY will make lean and obese people eat less and feel less hungry after a meal.
Who was studied?
12 obese people and 12 lean people. Everyone was between the age of 18 and 50. The average age was 29. No smokers were allowed in the study.
How was the study done?
People in the study ate a standard meal at 7:00 p.m. the night before the experiment and were not allowed to eat or drink anything but water after that. At 9:30 a.m. the next day some people were given PYY and some people were given saline (a substance not thought to affect appetite), but they were not told which one they received. Two hours later everyone was offered an all-you-can-eat buffet lunch. Researchers calculated how many calories each person ate and then let everyone go home and keep a diet diary of everything they ate for the next 24 hours. One week later everyone came back and the experiment was repeated, except that people who received PYY the first time now received saline and people who had received saline now received PYY.
What did the researchers find?
When comparing how much each person ate at the buffet, researchers found that if an obese person received PYY they ate 30% less than if they had received saline. When comparing diet diaries to see how much each person ate over the next 12 hours, researchers found that if an obese person received PYY they ate 26% less than if they had received saline. However, when comparing the last 12 hours of the diet diaries, the researchers found that obese people who received PYY ate a little more than if they had received saline. Overall, when researchers combined all of the calories eaten at the buffet and in the 24 hours of the diet diary, they found obese people who received PYY ate 16% less than if they had received saline. The results were similar for lean people. Also, obese people had lower levels than lean people of PYY in their blood both before and after the meal.
What were the limitations of the study?
The study involved only 24 people, was carried out over a short time (2 weeks) and only examined the effects of a single PYY dose. It is possible that if a person received PYY every day it would lose its effect and not reduce appetite. Interactions with other chemicals that may affect appetite were not considered.
What are the implications of the study?
PYY has the potential to help people curb their appetite and reduce obesity.
Summarized by Wells Chandler, College of Medicine, University of Vermont.
Summarized from "Inhibition of Food Intake in Obese Subjects by Peptide YY 3-36". Batterham, Rachel L. The New England Journal of Medicine, September 4, 2003, Volume 349, Issue 10, Pages 941-948
