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Dr. Jeffrey Friedman has fought for two decades to belie the
notion that obese people simply lack the willpower to change.
Instead, he says, they are victims of their own genes and shouldn't
be stigmatized for it.
He spent eight long years searching for proof of his genetic
theory of obesity - first advanced by Canadian-born Douglas
Coleman - and in 1994 discovered the hormone leptin, which is
largely responsible for controlling our metabolism and weight.
Leptin, from the Greek word meaning "thin," is produced
by fat cells and sends a signal to the brain reporting the amount
of fat stored. The brain then sends out signals that control
appetite and how much energy the body expends.
Friedman, a Howard Hughes Medical Researcher at New York's Rockefeller
University and one of five winners of this year's prestigious
$30,000 Gairdner Awards in medical science, will present his
findings at the Gairdner Public Lecture Tuesday night.
At first it was thought that leptin could be a magical cure
for obesity. When it was injected into obese mice, they quickly
lost weight. Drug giant Amgen spent $20 million to buy the rights
to make synthetic leptin. But the euphoria was short-lived.
Few obese participants who were given leptin in a large clinical
trial lost weight. In fact, most obese people produce too much
leptin, but their bodies don't process it properly.
What's clear is there is a complex physiologic system
that controls weight and maintains it within a range that most
people find very difficult to deviate from," Friedman said
in an interview.
The system is only now beginning to be understood, but he believes
it will eventually lead to far better treatments for obesity.
Already, the discovery has led to a whole new field of obesity
research and more than 10,000 scientific papers have been written
about leptin alone.
Friedman hesitates to talk about the so-called obesity epidemic,
although he agrees obesity is "a highly prevalent, very
important health problem."
But the extent to which it's increasing is debatable,"
he said. "I'm not sure the changes in rates of obesity
are as profound as you would believe reading the papers."
The average American weight gain in the last two decades has
been about seven to 10 pounds, he said, but many have used that
to argue obesity rates have doubled because the increase pushes
so many more people over the obesity threshold.
It also takes attention away from the real issue, he said.
"The more you believe rates of obesity have increased profoundly
in a generation or two, the more likely you are to attribute this
to changes in lifestyle and the less to differences in genes,"
Friedman said.
And the more people talk about epidemics of obesity, the more
they blame lifestyle issues - and the obese themselves.
That diverts attention from the way the problem needs to be
studied, which is like any other medical condition, he said.
"Instead, we simply assume it's all environmental and instruct
obese people to eat less and exercise more," he said. "It's
pretty clear that simple advice is no more likely to work today
than it was 2,500 years ago, when Hippocrates first suggested
it."
Obesity is "a highly politicized problem that plays into,
on one hand, Calvinist views about abstemiousness and, on the
other, economic interests served by playing up the epidemic
and the role of lifestyle in potentially treating it,"
he said.
The diet industry is "a multi-billion-dollar business"
that has an interest in having the public believe obesity is
a major problem that can be treated, he said. The pharmaceutical
industry also has a major interest in playing up obesity because
it stands to make millions finding new treatments.
"I think it's really important that the view of scientists
like myself be communicated to the public," Friedman said.
"This is an important problem that needs attention. The
key issue is how should we best approach it."
Obesity has many health consequences and people should use whatever
methods they can to lose weight, he said. Even a five- or 10-pound
weight loss can have a very positive effect on lowering high
blood pressure and the severity of Type 2 diabetes.
"But the more weight one needs to lose to improve their
health, the more difficult it becomes because of the complex
biological systems involved," he said.
It's known there are genetic factors that predispose some people to become
obese when they adopt the so-called Western lifestyle, he said.
What's not known is what is it about the Western lifestyle that
causes it.
"The answer is we don't really know," Friedman said.
"We don't know whether it's more food versus sedentary
lifestyle. The question is what are the genetic factors and
what are the lifestyle factors? Everyone makes assumptions about
it, but it's not really known with any certainty.
"The first step is to try to understand how the body normally
works, then to find what's different in the obese," he
said. "Then it will be possible to develop new treatments
that target specific molecules and biological pathways."
In the meantime, we must move away from blaming the obese, he
said.
"I think we have to be mindful of the fact that losing
weight is very intrinsically difficult and it forces people
to fight against their own biology," he said. "It's
important to not judge people harshly who are unable to lose
substantial amounts of weight."
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