24 September 1999

Fat On The Brain

by Kate Melville

It's the same story for thousands of overweight people fighting the battle of the bulge. They diet to lose weight, only to regain those extra pounds once they return to their normal eating habits.

However help may be at hand as researchers from Oregon Health Sciences University, may have identified the actual neurons involved in coordinating appetite and metabolism control in the brain! The research discovered one of the mechanisms in the brain that apparently memorizes and regulates a person's weight. The mechanism located in the hypothalamus has been named the adipostat, due to the fact that it essentially acts as a fat thermostat.

Previous studies have shown how the brain reacts to a change in diet and why losing weight can be a battle for many. Apparently when you lose weight, the body thinks there's something wrong (like starvation or disease) and it initiates a number of responses to prevent you from losing weight and even to help you put weight back on.

These responses include a decrease in the metabolic rate and an increase in muscle efficiency to limit energy loss. For years, scientists have proposed the existence of an adipostat in the brain, but until now, it's mechanism has remained a mystery. The Oregon team has now identified individual neurons within the hypothalamus with the precise properties of the long-predicted adipostat. To find the adipostat, researchers traced the routes of two fiber pathways that appear to play a role in feeding and metabolism. Cone compares the process to tracing electrical wires in your home back to the fuse box.

One of the pathways to the adipostat, called the NPY/AGRP, stimulates feeding. The other pathway, called the MSH, inhibits feeding and is involved in the normal maintenance of metabolic rates. While this is a real breakthrough (although perhaps not if you own a weight loss clinic) there still lots more to be learned about the body's metabolism controls.