Overweight People Have Excess Amount Of Appetite Suppressant Leptin

Obesity researcher Jose F. Caro has just deflated much of the hope and hype behind leptin - the appetite-suppressing substance discovered last year that miraculously melted away excess fat in obese laboratory mice.

Alas, mice are not men.

People and mice both produce the hormone leptin, but obese mice have a shortage of the stuff, while overweight people have a surplus - their blood carries an average of four times the amount of leptin found in thin people, according to a study by Caro and Robert Considine both of Philadelphia’s Jefferson Medical College.

Therefore, getting extra leptin is not likely to help most overweight people to get thin.

“If you have four times the normal amount of leptin, it’s unreasonable to think you would respond to a leptin shot,” says Caro.

This new research adds to a growing body of evidence that science won’t easily overrule Mother Nature, who gave humans the propensity to store fat as a protection against famine.

But Caro argues that his study points to another line of attack in the molecular biologists’ war against fat.

The fact that his obese subjects made so much leptin is a sign they likely suffer from a defect in the way the body processes it.

“This tells you loud and clear that people with obesity have a resistance to leptin,” he says. Caro and other researchers speculate that a treatment aimed at reversing this resistance would help people shed pounds.

The study, based on measurements of blood leptin in 136 people of normal weight and 139 overweight people, is published in today’s New England Journal of Medicine.