weight control: obese lack spike of hunger hormone

Researchers studying hormones associated with food intake and metabolism have discovered a hitherto unknown biological feature of obesity. Julio Licinio of the University of California at Los Angeles and colleagues have found that obese people lack a normal nighttime spike of ghrelin, a hormone that promotes hunger. Levels of ghrelin in the blood show regular patterns in a 24-hour cycle — normally increasing before meals, and decreasing after eating. In this week’s Proceedings of the National Academy of Sciences Online Early Edition, the researchers report studying five obese and five lean young men, collecting samples of their blood every seven minutes over 24 hours. They found that the lean men had a surge of ghrelin between midnight and 6 a.m. — when they were sleeping and so didn’t eat. The obese subjects had higher ghrelin levels when they were awake and capable of eating, and had no hormone surge during the night. The authors said they hope their finding might point out new directions for treating obesity.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 6/29/2004.