Is obesity a disease? Or is it a result of bad lifestyle choices?
Opinions were split about 50:50 among the attendees at a recent Cleveland Clinic Medical Innovation Summit on Obesity, Diabetes, and the Metabolic Crisis. Then the speaker after the informal poll (a show of hands) said, "Obesity is 80 to 90% heredity, exceeded only by height" in its genetic cause.
That speaker was Jeffrey Friedman, who discovered leptin in 1994 and recently received a Lasker prize. The Lasker is considered a harbinger of a Nobel Prize.
Friedman went on to show slides of identical twins. The body builds of the identical twins were the same: if one twin was fat, so was the other. This was also true of twins raised apart.
Body builds of nonidentical twins were often different, despite having been raised together. And body builds of adopted children resemble those of their birth parents more than those of their adoptive parents, who would naturally influence the food that they were given.
He also described a boy who was one of the rare people who produce no leptin. Before being treated with leptin, the boy ate 1125 calories in a single test meal, about half of what an adult would eat in an entire day. At the age of 4, he weighed 90 pounds.
Then he received leptin injections and soon ate only 180 calories when offered the same meal. At the age of 6, despite being taller, he weighed only 72 pounds. A photograph showed that with the regular leptin injections he became not only normal weight, but also a bit on the thin side.
Unfortunately, most obese people do not have leptin deficiency but leptin resistance, analogous to insulin deficiency and insulin resistance, so leptin injections are not the solution for the vast majority of obese people.
In 2009, Friedman wrote an article in Newsweek arguing that obesity is genetic. He said at the conference that he received a lot of comments about the article saying, "That's crap." From the general public, this is somewhat understandable. Most people aren't able to understand scientific evidence. They read popularizations that may support their own preconceived views.
But when 50% of physicians and other leaders in the field of obesity and diabetes research think that obesity is caused by sloth and gluttony, we have a problem.
Almost everyone at the summit agreed that there's an obesity epidemic today. Philip Schauer, director of the Cleveland Clinic Bariatric and Metabolic Institute, said that the prevalence of obesity is expected to double worldwide in the next 10 years. Alex Gorsky, worldwide chairman of medical devices and diagnostics at Johnson & Johnson, said that in China, childhood obesity has increased 30 times in the past 15 years. And the Centers for Disease Control and prevention recently predicted that by 2050, 30% of Americans will have type 2 diabetes (currently 10% have been diagnosed with type 2).
Friedman appeared to support this view that there's an obesity "epidemic" today, showing a slide of a quote: "I believe no age did ever afford more instances of corpulency than our own."
Then he told us this quote was from a physician named Thomas Short . . . written in 1727.
In other words, obesity has always been with us. There have always been fat people and skinny people as well as people in between. Friedman pointed out that when you have cutoff points for obesity, a small change in weight may shift a lot of people from one category into another without a great overall change.
Despite all the bad press about obesity (and all the photos of headless people with bulging stomachs), he said a 33% increase in obesity reflects an average weight gain of only 10 pounds.
Nevertheless, most of us think that obesity is not a good thing. Most Americans would rather not be fat, if they had a choice (whereas in some cultures, being fat is a sign of success). But is it hopeless to expect any progress if obesity is mostly genetic?
I don't think so. I think both genetics and environment are important. Your genes can make you prone to easy weight gain and difficult weight loss. But if there's not much food available, you won't gain weight. You don't see a lot of people gaining weight in concentration camps or famine regions.
But when food is abundant and restaurant serving sizes are too large, then the people with the genetic tendency to store fat will gain a lot of weight, whereas people without those genes will be able to eat all the nutrition-free junk food they want, and they'll remain skinny.
It's like type 2 diabetes. Obesity is associated with type 2. But not all fat people become diabetic. If you have beta cells that can produce tons of insulin, you won't get type 2 no matter how fat you are.
When Friedman initially posed the possible cause of obesity, he said it could be genetic, or it could be environmental. Then he said the view that it's caused by eating too much and not exercising enough "is mostly favored by thin people."
Some of us think it's time to stop blaming fat people for their weight. Now we have a Lasker recipient on our side. As Friedman said, we need "a war on obesity, but not the obese." We need to focus on improving health instead of focusing on losing weight.
We need to figure out how to help the people with the bad luck to inherit easy-weight-gaining genes cope with an environment that brings out those fat-storing genes.
If we work together instead of assigning blame, perhaps we can fix this problem.
Published On: November 08, 2010