UBC Reports | Vol. 51 | No. 1 | Jan. 10, 2005

Do You Really Want That Bite?

Resistance to signals from the "obesity hormone" may feed drive to eat, and contribute to the onset of diabetes

By Hilary Thomson

How many of us have resolved to lose weight in the New Year? Quick, put down that hamburger and raise your hand.

Obesity, along with its debilitating partner, diabetes, is becoming recognized as one of North America’s major health concerns. Scientists and clinicians know the two conditions are linked -- but how?

Timothy Kieffer aims to find out. A diabetes researcher and associate professor in the departments of cellular and physiological sciences and surgery, Kieffer has recently received almost $300,000 over three years from the Canadian Institutes of Health Research to explore the connection between a hormone called leptin and the development of obesity and diabetes.

“We’ve learned that the mechanisms of obesity are complex -- it’s not a matter of gluttony,” says Kieffer. “We also know that maintaining weight loss is difficult because people are fighting powerful hormonal effects, including the fall in leptin levels.”

Leptin -- also known as the obesity hormone -- is normally produced by fat cells. It tells the part of the brain that controls eating how much fat you have, information that helps the body minimize changes in body weight. When an individual loses fat, leptin levels fall. The brain interprets the drop as a message that the body is starving and must eat more and conserve energy so body weight and leptin levels can return to normal.

Obese people produce lots of leptin, but are somehow resistant to its signals. Because it can’t “hear” the signal, the brain thinks there is insufficient leptin and the stimulus to eat more and conserve energy gets activated. Kieffer believes that leptin resistance may contribute to the development of diabetes associated with obesity.

One of only a few researchers world wide looking at the connection, Kieffer’s work could lead to new ways to control body weight and reduce the risk of diabetes.

In the new study, he will look at leptin’s powerful effects on regulating blood sugar levels and how to reverse leptin resistance. Research on the leptin connection may lead to medications that could help people maintain a healthy weight and reduce the risk of diabetes.

“But medication to regulate leptin won’t be a magic bullet,” says Kieffer. “Fat isn’t just a matter of genetics -- diet and exercise do play an important role. How the body regulates weight is just a lot more complex than we’d earlier believed. Ultimately we hope to eliminate Type 2 diabetes by developing an approach that can be combined with diet and exercise to maintain a health body weight.”

Diabetes could Double in 20 Years

According to the World Health Organization, 177 million people were suffering from diabetes in 2000. By 2025, that number is expected to jump to 300 million. The U.S. Centers for Disease Control estimate that one-third of American children born in 2000 will develop the disease.

A huge drain on health budgets, diabetes care costs Canadians about $13 billion annually. The U.S. spent $132 billion to manage the disease in 2002.

About 80 per cent of patients with Type 2 diabetes (formerly known as adult onset diabetes) are obese. With more children becoming overweight, there has also been a steady rise in the number of kids with Type 2 diabetes.

Kieffer’s study is also supported by the Michael Smith Foundation for Health Research.

For more information on diabetes, visit the Canadian Diabetes Association website at www.diabetes.ca and click on About Diabetes.