Diets Don't Work Long-Term
Most Who Go on Diets Gain Weight Back; Lifestyle Change Needed
Problems With Diet Studies continued...
"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
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
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.
"A lot of people go on a low-calorie diet for a few weeks and expect to
lose a lot of weight," van Dam tells WebMD. "But if you do a crash
diet, you will only regain the weight."
If you take medicine to control high blood pressure or high cholesterol, van
Dam says, you would expect your blood pressure or cholesterol level to go back
up when you stopped taking your medicine. A weight-control diet works the same
way for obesity.
Why is it so hard to lose weight? A big part of the problem, van Dam and
Fernstrom say, is that people try to diet in isolation.
"Diet is affected by social issues, by what you do when you are with
your family and your friends," van Dam says. "In the current American
setting, which really encourages unhealthy eating and dietary patterns, it is
difficult to keep these lifestyle changes going."