Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Problems With Diet Studies continued...

Why don't diets work? Mann says there are two issues. The first is that it's just plain hard for people to change their eating behaviors. And the second reason is that even if you do succeed at a diet, the rule of diminishing returns comes into play.

"When you keep to a reduced-calorie diet, your body makes metabolic adjustments that make it harder and harder for you to lose weight," Mann says. "Your body becomes very efficient, and you have to eat less and less to continue to lose weight. If you had the will to go on a diet, the fact that it steadily becomes less and less effective makes it even harder to stick to it."

That's true, agrees Madelyn Fernstrom, PhD, founder and director of the Weight Management Center at the University of Pittsburgh and diet and nutrition editor for NBC's Today show.

But Fernstrom worries that people will get the idea from this that their diets don't matter. And she's worried even more that the Mann report will discourage people from trying to lose weight.

"'Diets don't work' is only half the story," Fernstrom tells WebMD. "Lifestyle change will work if you have realistic expectations, good support, and choose a plan that you can stick with -- a plan that will give you moderate change over a long time."

That doesn't mean weight loss is easy. There's a myth, Fernstrom says, that normal-weight people can eat anything they want and don't need a strict exercise regimen. But that's true for only a very small number of people. Most people who have a healthy weight have to work at it.

"It is really hard to lose weight, and it is even harder to keep it off," Fernstrom says. "You can't cry about this. You must maintain hope. We just have to develop better strategies to keep people on track."

How to Lose Weight for Good

The basic problem is that people think diets are something you do for a little while before going back to your old lifestyle, says obesity expert Rob M. van Dam, PhD, assistant professor of medicine at Harvard Medical School.

Healthy Recipe Finder

Browse our collection of healthy, delicious recipes, from WebMD and Eating Well magazine.

Top searches: Chicken, Chocolate, Salad, Desserts, Soup

Heart Rate Calculator

Ensure you're exercising hard enough to get a good workout, but not strain your heart.

While you are exercising, you should count between...