肥胖症是不是病？

STEVE INSKEEP, HOST: It's MORNING EDITION from NPR News. I'm Steve Inskeep.

DAVID GREENE, HOST: And I'm David Greene, good morning.

Today in Your Health, we're taking time to answer more questions that you have sent to us about the Affordable Care Act. That's the new healthcare law taking effect next month. But first, we're going to hear about treatments for obesity. Many insurance plans don't cover treatments, such as counseling on diet and exercise, medications and weight-loss surgery. But that might all change under the Affordable Care Act. This is largely due to a growing acceptance that obesity is a disease, not a lifestyle choice.

NPR's Patti Neighmond has more.

PATTI NEIGHMOND, BYLINE: When Melissa Merenda went to college, she didn't gain the Freshman 15. It was more like the Freshman 30.

MELISSA MERENDA: Just the way that I ate and the lifestyle and, you know, drinking in college didn't help.

NEIGHMOND: Merenda continued gaining even after college. At 5 foot 5, she was the heaviest she'd ever been: 216 pounds. She decided it was time to get serious. She started walking a lot. She joined a volleyball team and drastically changed her diet. Even so, after a few months, she'd only lost seven pounds. Merenda ended up going to the Massachusetts General Hospital Weight Clinic.

MERENDA: By the time I got there, I was kind of at wit's end. Nobody would listen to me and I was just like, well, what's the point of doing all of this if I'm just going to, you know, be fat. I might as well just eat cheesecake and be happy, not bust my butt trying to work out

NEIGHMOND: The obesity program is headed by Dr. Lee Kaplan, a firm believer that obesity is a disease which puts some people, like Merenda, at a disadvantage when it comes to gaining weight.

DR. LEE KAPLAN: We're all different. We're wired in slightly different ways. And those subtle differences are reflected in how the body deals with energy stores or how the body deals with its fat.

NEIGHMOND: And many of those differences are inherited. There are thousands of genes in the body and Kaplan says about 100 of them are involved in making some people more susceptible to weight gain.

Harvard Professor Dr. Osama Hamdy, directs the obesity program at the Joslin Diabetes Center in Boston. He says classifying obesity as a disease is long overdue.

DR. OSAMA HAMDY: The reality is if you have that genetic susceptibility to gain weight, you will gain weight easily no matter what

NEIGHMOND: Genetic susceptibility has to do with hormones and chemical systems in the body that direct appetite, metabolism and the absorption of nutrients and fat. One of those hormones is leptin. It tells the body when it's full. Hamdy says the majority of people who are obese are resistant to leptin.

HAMDY: The brain is shielded from the information on how much fat you have in your body. And the brain is under the assumption all the time that you need more fat because it cannot sense that leptin.

NEIGHMOND: Leptin tells the body when to stop eating. Other hormones make some people hungry more often than others. Then there's a system of brain chemicals that, if not functioning properly, fail to tell the body to stop eating what it likes. Instead they do the opposite.

HAMDY: This is exactly what you like, this is what you love, continue to eat it.

NEIGHMOND: Hamdy says defining obesity as a disease should encourage more doctors to offer treatments like gastric bypass surgery and medication. Two new obesity drugs were recently approved by the FDA. But not everybody thinks calling obesity a disease is a good idea.

Linda Bacon is a nutritionist in San Francisco.

LINDA BACON: It sets up people who are heavier up to believe there's something wrong with them and that they're going to get sick unless they do something about it. Then that gets used as justification: oh, I have to get weight loss surgery to ward off the potential of a future disease. But that future disease may never exist.

NEIGHMOND: Others worry that overweight people may just opt for medication, before even trying to seriously change their diet and exercise routine.

Patti Neighmond, NPR News.