Weight Loss Drugs: How Much Do Diet Pills Help?

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Weight Loss Drugs: How Much Do Diet Pills Help?

The truth about weight loss medications and supplements.

By Kathleen Zelman, MPH, RD/LD
WebMD Weight Loss Clinic - Feature

Reviewed By Louise Chang, MD

"Clinically proven to help you lose weight without being hungry or working out for hours at the gym!"

You've seen the ads promising successful weight loss by taking diet drugs or weight loss supplements, but do they really deliver results? Could weight loss medications and over-the-counter supplements really help to reverse the obesity epidemic?

Experts who spoke to WebMD agreed that there's no such thing as a quick fix or magic bullet when it comes to losing weight. Weight loss medications (not to be confused with dietary supplements) can help you lose weight, but only if you also cut calories and get moving. And effective weight loss, they say, is slow and gradual -- anywhere from 1/2 to 2 pounds per week, even with the help of diet drugs.

"Weight loss medications can be modestly effective, and enhance weight loss by 8%-10%, but medication does not work for everyone," says Robert Kushner, MD, a professor of medicine at Northwest University.

Kushner estimates that about a third of his patients respond well to medication. But he points out that drug therapy is only one part of a lifestyle that also includes a healthy eating plan, regular exercise, and behavior modification.

Louis Aronne, MD, director of the comprehensive weight control program at New York Presbyterian Cornell Weill Medical Center, agrees.

"Medications can really make a difference for some people, but it must be part of a complete lifestyle that includes diet and exercise," he says.

One problem, says Aronne, it is that there are simply not enough medications to choose from.

"We have numerous medications for conditions like high blood pressure, but when it comes to treating obesity we only have a few, and we could use 5-10 different types of weight loss drugs," he says.

Weight Loss Drugs and How They Work

There are two basic types of weight loss drugs -- prescription drugs, which have been around for years, and now, with the release of Alli, over-the-counter medication. Other over-the-counter weight loss remedies are considered dietary supplements; they do not undergo the same type of FDA approval process as drugs.

"Approved weight loss drugs must prove they are safe and effective with strong scientific evidence in order to pass the stringent FDA approval process," says Aronne, former president of the North American Association for the Study of Obesity (NAASO).

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In the prescription drug category, there are basically three choices, Xenical (orlistat), Meridia (sibutramine), and phentermine.

Xenical (orlistat) is a fat blocker that prevents fat from being completely absorbed in the gastrointestinal tract. Prescription strength is 120 milligrams; over-the-counter Alli is the same drug at half strength, or 60 milligrams.

Fat blockers reduce fat absorption and, as a result, some people are plagued with oily discharge, fatty stools, gas, and/or inability to control bowel movements. These side effects are the result of the fat not being absorbed by the body. Eating a low-fat diet reduces the risk of potential side effects. But if your diet is already low in fat, you may see less of an impact from the medication, as there is less fat to block.

Xenical or Alli is safe for almost anyone because the drug is not absorbed, says Kushner. "I frequently prescribed it to cardiovascular patients because it is so safe," he says.

Patients must be willing to stick to a low-fat diet. These drugs have a built-in feedback system. "If you eat a high-fat diet, you will experience the side effects, so to avoid the unpleasant effects, you need to reduce the fat in your diet," says Aronne.

Not only do these drugs block fat, they have the potential to block other nutrients.

"Take a once-daily multivitamin mineral for nutritional insurance to help compensate for any losses and don't take it at the same time as the medication," says Dawn Jackson-Blatner, a spokesperson for the American Dietetic Association.

Meridia (sibutramine) helps reduce hunger by working on the appetite control center in the brain that makes you feel full.

"Meridia can help add 5%-10% additive weight loss that you would not get with diet and exercise alone" says Aronne.

Kushner prescribes Merida to patients who struggle with cravings and have trouble knowing when to stop eating. Aronne says that younger patients who are at a low risk for heart disease are good candidates.

Side effects include dry mouth, constipation, and insomnia. Meridia should not be used by anyone with cardiovascular risk factors.

"We recommend regular blood pressure checks for anyone on Merida," says Blatner.

Phentermine is generic, the least expensive of the medications, and has been on the market the longest. Once a part of the famed fen-phen combination weight loss drug, Phentermine works to decrease appetite.

It is the most widely used weight loss drug. While it's officially approved only as a short-term drug, some doctors use it as long term therapy.

"I use phentermine for people with strong appetites. [It] seems to work best on reducing hunger and the number of eating episodes. I also like it because it is generic, and inexpensive for patients who do not have insurance coverage," says Kushner.

Side effects may include depression, insomnia, increased blood pressure, irritability, and nervousness.

While these are the only medications approved for weight loss, some people also lose weight on prescribed medications used to treat other conditions such as depression, seizures, and diabetes.

Insurance coverage of these weight loss medications varies. Some companies will cover them completely, some partially, and some not at all.

Over-the-Counter Weight Loss Supplements

Dietary supplements should not be confused with weight loss medications. Most experts give little credence to the weight loss remedies that line drugstore shelves.

"There is a bewildering array of weight loss dietary supplements, but the sad fact is, there is no credible medical evidence that the supplements are safe, effective, and perform the way they claim," says Aronne.

Even so, many people plunk down their money. Promises from manufacturers range from reduced appetite to increased metabolism. But these claims are loosely regulated, and if they sound too good to be true -- chances are, they are.

"It is not as simple as many of the ads claim, and invariably what happens is patients try the supplements, they don't deliver as promised, and patients gain another notch on their failure belt," says Kushner.

Blatner suggests talking to your doctor or a registered dietitian before buying supplements.

"Wouldn't you rather take an FDA-approved medication than take the risk of choosing an over-the-counter weight loss remedy that may not be safe or effective?" she asks.

The Today show nutritionist Joy Bauer, RD, tries to inspire her clients to lose weight the old- fashioned way.

"Very few of my clients rely on supplements or drugs, and my advice is to find the natural health benefits in food," she says. "It is much better to drink a hot cup of green tea that is soothing, relaxing, gives you something to do with your hands and mouth, and delivers the benefits [of green tea] in a much better form than taking a pill."

Who Can Use Weight Loss Medications?

Not everyone is a candidate for diet drugs.

"About one-third of my patients are on weight loss drugs, but they don't start off that way," says Kushner. "The initial approach is to change their lifestyle, and after about 4-6 months of being engaged in a healthy lifestyle, if they are not getting results of 1- to 2-pound loss per week, we consider drugs."

He says another third of his patients have surgery, and the last third are successful with what he calls "lifestyle medicine."

So who does do well on weight loss drugs? Before prescribing drugs, experts look at whether patients are eating a variety of healthy food, controlling portion sizes, using strategies to monitor and plan their meals, adhering to reasonable calories goals, and getting exercise. If the traditional approach to weight loss is not working, drugs are an option.

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But don't think that if you are 5 pounds overweight, you are going to be prescribed weight loss medication.

"We follow the NHLBI [National Heart, Lung and Blood Institute] guidelines that patients must have a BMI of 27 along with other complaints, or a BMI of 30, before using drug therapy," says Aronne, editor of The Practical Guide: Identification, Evaluation and Treatment of Overweight and Obesity in Adults.

Even when a patient meets the criteria and takes the drugs as an adjunct to a healthy lifestyle, there is no guarantee they will work.

"We can usually tell who will be a responder in 4-6 weeks," Blatner says.

Published October 5, 2007.


SOURCES: Joy Bauer, MS, RD,Today show nutritionist; author,Joy Bauer's Food Cures. Dawn Jackson Blatner, RD, spokesperson, American Dietetic Association. Robert Kushner, MD, professor of medicine, Northwestern University; author, Dr. Kushner's Personality Diet. Louis Aronne, MD, director, comprehensive weight control program, New York Presbyterian Weill Cornell Medical Center. WebMD Feature: "All About Alli." National Institutes of Health Weight Control Network web site. The Practical Guide: Identification, Evaluation and Treatment of Overweight and Obesity in Adults, NHLBI, 2000.

©2007 WebMD Inc. All rights reserved.


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Reviewed on 10/8/2007

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