Three recent studies examined the effects of diet pills, lifestyle changes and daily I weight monitoring to try to determine what works best in the fight against obesity.

Study #1: Meridia Plus Lifestyle Changes

The first study found that the weight-loss drug sibutramine (Meridia) is most effective when users also eat right and exercise.

In a one-year trial, researchers gave 224 obese adults 15 milligrams (mg) of Meridia every day. They randomly assigned some people to also receive counseling to teach them how to keep food records, shop for healthy foods and how to stay away from all-you-can-eat buffets and fast-food restaurants.

Lead researcher Dr. Thomas Wadden, director of the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine, says these changes, along with a healthy diet and physical activity, "help you modify the external environment," while drugs such as Meridia "help modify the internal environment," working on brain chemicals to lower appetite and help patients feel fuller sooner.

The combination seems to work. According to the researchers, people taking Meridia who also changed their lifestyles lost an average of 25 pounds, more than twice as much as those who took the drug but made no lifestyle changes (11 pounds).

Most obesity experts say lifestyle changes, especially improved diet and exercise, are the real keys to losing weight. But many overweight Americans still find it tough, according to Wadden.

"There's nothing worse than to be watching your calories and exercising, but the scale just doesn't budge," says Wadden. "You just feel like, 'My efforts are for naught.' That's when people tend to give up."

And that's when diet pills may come in handy, says Dr. Susan Yanovski, director of the Obesity and Eating Disorders Program at the US National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK).

'All the weight-loss drugs have shown generally what I'd consider a modest weight loss compared with placebo, usually somewhere in the range of five to 15 pounds additional weight loss," says Yanovski.

Weight-loss pills "should not be used alone," Yanovski advises.

"Don't look for a quick fix from the drug store. Combining therapies seems to be much more effective than drug treatment alone," she says.

Study after study has shown that obesity can easily return when individuals stop exercising and eating right, or if they discontinue a weight loss medication.

"We now realize that people may have to take weight loss medications on a long-term basis," 'Wadden says, "just like they have to take other medications, such as those that control cholesterol or high blood pressure."

In the case of Meridia, that means long-term physician monitoring, because the drug can trigger a rise in pulse rate and blood pressure in approximately 10% of users, the researchers say'.

Study #2: A New Weight-Loss Drug

Meridia is just one of two weight loss drugs currently approved for use by the US Food and Drug Administration (FDA).

The other is orlistat (Xenical), and a third medication, rimonabant (Acomplia), showed promising results in a trial, and is currently undergoing FDA review.

The international study on rimonabant was led by Jean-Pierre Despres of Laval University in Sainte-Foy, Quebec, Canada, and involved more than 1,000 overweight or obese patients who had untreated high cholesterol The participants were placed on a low-calorie diet and given either dally rimonabant (at doses of 5 or 20 mg) or a placebo.

Rimonabant helped participants lose an average of approximately 15 pounds during one year. And the drug may have the added health benefit of lowering levels of dangerous blood fats known as triglycerides and boosting levels of HDL ('good') cholesterol.

"We know that rimonabant improves [cardiovascular risk factors, but we don't know yet if that translates into a reduction in heart disease or death," Yanovski says.

"Rimonabant is a little bit different in that it acts not only on the brain but also on other tissues in the body, such as fat cells and those in the gastrointestinal tract," she says.

Study #3: Keeping Track

A third study found that people who get in the habit of weighing themselves every day are more successful at losing weight than those who do not monitor their weight daily.

The study looked at more than 3,000 obese or overweight individuals enrolled in weight-loss programs for two years.

Researchers at the University of Minnesota found that those who checked their weight daily lost more than those who didn't.

If people see that they have gained a few pounds, they may realize it's time to do something. It's probably easier to make that small correction than to make a larger one after they realize they have gained more than just a few pounds, says lead researcher Jennifer Linde.

All that monitoring and hard work could pay off, though-even minor weight loss can trigger major health benefits.

According to Wadden, "If people lost just 7% of their initial body weight-approximately 15 pounds through 150 minutes of exercise per week-they reduced their risk of developing type2 diabetes by 58%. A little bit of weight loss goes a long way."

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