Quack Diet Red Flags

Warning: Quick weight loss! No effort required!

By Jeanie Lerche Davis
WebMD Weight Loss Clinic - Feature

Reviewed By Brunilda Nazario, MD

Lose that weight -- you know you should. But the sheer numbers of weight loss programs sometimes confuse the issue.

The cabbage diet! The rice diet! The blood type diet! Atkins! South Beach! No carb! Low carb! There's even a Jesus diet (sans loaves and fishes).

"People who want to lose weight are a very vulnerable group because they're very frustrated," Kathleen Zelman, MPH, RD/LD, director of nutrition for the WebMD Weight Loss Clinic, tells WebMD. "Weight loss is hard, and everybody is looking for a silver bullet."

How can you discern which weight loss claims are true or false? Here's some advice from Zelman and from the Federal Trade Commission:

Does the diet promote rapid weight loss?

That's a clear signal it's unrealistic, says Zelman. When you start a diet, water weight is the first to go, she explains. If you lose much more than two pounds a week, you're drawing from both fat and muscles. That's not good, because muscle is one big factor that controls your metabolism. If you lose muscle mass, your metabolism will slow down. That's how the yo-yo cycle begins -- and that's one reason why some diets don't work, she explains.

"That's why we advocate losing weight slowly and gradually, so you're losing one to two pounds per week," Zelman says. "You're eating more food than diets allow, but you're tapping into stored fat more efficiently."

Does the weight loss program involve eating just one food -- or eliminating whole food groups?

"That's crazy," says Zelman. "No one can stay on those diets very long."

Sure, you can do it in the short term -- with some success, she says. "If you're eating all the cabbage or meat you want, you go into a state of ketosis. This causes your appetite to go away, so ultimately you don't eat as much -- probably you're down to a 1,000-calorie diet. Anyone on a 1,000-calorie diet will lose weight.

"Even the strangest diets will pull weight off you, because the basic formula to weight loss is burning more calories than you eat."

Does the program help you change long-term eating habits?

If not, you'll just get caught up in a never-ending lose-gain cycle -- better known as "yo-yo" dieting.

Most diets are short-term fixes for a long-term problem, says Zelman. "People who get slim and stay that way have changed their eating habits and attitudes toward food."

Does it involve exercise?

If it doesn't, you will gain the weight back. "Research shows that individuals who exercise on a regular basis have much greater success at losing weight and keeping it off ... Exercise is critical to weight loss success," Cedric Bryant, PhD, chief exercise physiologist for the American Council on Exercise, tells WebMD.

You need an hour of aerobic exercise -- at least five times per week -- if you seriously want to lose weight, says Bryant. "That doesn't need to be in one concentrated dose, because calorie-burning effects accumulate over time."

Also, you need strength training two times a week to build muscle. Lifting weights or working with rubber tubes helps maintain and can also increase the level of lean body mass -- which helps your metabolism burn calories.

"Two-thirds of the calories a person burns over the course of a day are from resting metabolism," says Bryant. "If you're on a restricted diet (decreasing calories and nutrients) and not doing resistance training (to build muscle), it's not uncommon to see resting metabolism decrease -- so you won't lose weight."

Are supplements, creams, or patches involved?

If so, forget it. "It's the old saying, 'if it sounds too good to be true, it is.' Why would we have an obesity epidemic if it was as easy as popping a pill?" says Zelman.

"By and large, products are not capable of helping you lose weight. Ephedra has been banned from the market, and it was the major ingredient of weight-loss supplements." That should send a big message: These things are either not healthy or do not work, she says.

Products that block absorption of fat, such as Xenical or Orlistat, may have only minor weight-loss potential -- and they're expensive, says Zelman.

The problem: "These are all Band-Aid approaches to the problem. Even though it's not sexy, and not any fun, people know what they need to do. You don't need to be a rocket scientist to know that eating sweets, eating constantly, drinking alcohol, eating fast food are all the things that add extra calories."

Is there sound research behind the weight-loss program?

"Not all studies are created equal, and there are plenty sponsored by companies to get the answers they want. So a fair amount of skepticism is in order," says Zelman.