For More Information, Please Call Us At call 603.524.3211

Health Information Library

 
Categories > Diet and Nutrition > Weight management

Mayo Content Display

Weighing in on diet-control medications

» Overweight or obese?

» Two pharmaceuticals

» Beware of sticker shock

The BMI formula

You can determine your body-mass index (BMI) using the following formula and a pocket calculator:

BMI=your weight in pounds multiplied by 705, divided by your height in inches, then divided again by your height in inches

Your target value using the BMI scale is 18.5 to 24.9. Values of less than 18.5 indicate underweight; values from 25 to 29.9 indicate overweight; values of more than 30 indicate obesity.

Extreme option: stomach surgery

Surgically reducing the size of the stomach is becoming a popular treatment for extremely obese patients whose BMI exceeds 40, or who are 100 pounds overweight. The American Society for Bariatric Surgery (ASBS) contends that such procedures should be regarded as medical necessities, not cosmetic procedures. Bariatric surgery is “the only proven method of achieving long-term weight control” in the extremely obese, the group says. “[Their ability] to lose significant weight by nonsurgical means is minuscule.”

Two types of procedures are in common use today: restrictive and combined restrictive/malabsorptive. In restrictive operations, surgeons use a band or a band and staples to form a small pouch at the top of the stomach, limiting the amount of food the patient can eat. In combined operations, doctors create the pouch and graft a new tube into the small intestine so that food is less well-digested. Both procedures can be done either traditionally, through “open” abdominal surgery, or laparoscopically, through a small incision in the abdomen.

Examples of obese patients losing half their weight within two years of undergoing bariatric surgery are not uncommon. Studies show that patients keep the weight off for as long as 14 years after their procedures. In addition, patients say they’re healthier, happier and better-looking following the operation. For most of them, having small meals four or five times a day—eating slowly and chewing thoroughly to avoid stomach upset—and taking daily dietary supplements is a small price to pay for their new lifestyle. But the ASBS warns that stomach surgery, a major medical procedure, is a last-resort therapy that should be thoroughly discussed with your doctor before proceeding.

Need to lose a few pounds before you can fit into your fall wardrobe? Your neighborhood pharmacy has a complete line of over-the-counter diet aids, but you only seem to lose weight for a few weeks using them. This time, you’ve decided to ask your doctor for a prescription for one of the weight-control drugs you’ve read about.

Well, don’t be surprised if your doctor suggests exercise and better eating instead. Prescription diet drugs are targeted only to patients with serious, health-endangering weight problems, not to the millions of Americans who should lose just 10 or 15 pounds. For those people, the only surefire way to lose weight—and keep it off—is to make dietary and lifestyle changes, researchers say.

Overweight or obese?

An estimated 58 million Americans are 20 percent or more overweight. Although many people think their “ideal weight” means looking like a fat-free supermodel or an Olympic distance runner, doctors use a more scientific approach: the body-mass index, or BMI. Basically, the BMI is a math formula that compares a person’s weight to his or her height and gives it a value. (See “The BMI Formula.”) A BMI between 18.5 and 24.9 is usually healthy; 25 to 29.9 indicates a patient is overweight; 30 or more (27 for diabetics), along with a waistline of 35 inches or more for women and 40 inches for men, is a medical red-alert for obesity. (You’re also obese if you’re more than 30 pounds over the government’s established weight ranges for your height, age and gender.) Extreme obesity is defined as a BMI exceeding 40.

If you’re overweight by BMI guidelines, most doctors will direct you to eat better and hit the gym.

Over-the-counter diet aids and some herbal products may help to quiet your growling stomach. But nutritionists warn these aids are not an appropriate long-term approach to weight control. Speak with your doctor about side effects, possible drug interactions and the ingredient ephedra, a Chinese herbal extract that has been implicated in stroke and even several deaths.

Truly obese patients whose BMI exceeds 30 have a chronic disease. Obesity is defined as an excess of body fat, and it’s a major risk factor for coronary heart disease, stroke, diabetes and hypertension, according to the American Heart Association.

Two pharmaceuticals

Since the fen-phen scare of the late 1990s, only two prescription obesity drugs have been approved by the U.S. Food and Drug Administration: Meridia, containing sibutramine, and Xenical, containing orlistat. A lower-dose version of orlistat, called Alli, has recently been approved by the FDA for over-the-counter sale. These drugs, taken daily as pills, work in different ways to help patients lose weight, although sometimes they are prescribed together. Both prescription drugs are FDA-approved only for clinically obese patients—those with a BMI exceeding 30, or diabetics and those with cardiovascular disease, high cholesterol or high blood pressure with a BMI of 27 or higher. Alli is approved for use by overweight adults along with a reduced-calorie, low-fat diet and exercise program.

Meridia works similarly to fenfluramine (the “fen” in fen-phen) by blocking serotonin, a brain chemical that stimulates appetite. Meridia makes a patient feel less hungry and more “full” earlier in the meal, so he or she will lose weight. In studies, patients lost at least 4 pounds in the first month using Meridia.

Meridia doesn’t appear to cause heart-valve disease like fenfluramine might have, which led to its recall in September 1997. However, the drug’s side effects include increased blood pressure, faster heart rate, headaches and insomnia in some patients. And doctors caution that the drug’s effect on appetite sometimes doesn’t fully kick in for three weeks to a month, which can be frustrating.

Xenical and Alli, on the other hand, work within 48 hours using a completely different mechanism. The drug orlistat blocks the release of lipases—enzymes in the digestive tract that break down dietary fats. It can block up to 30 percent of these fats from being digested; instead, the patient excretes them. Side effects on the gastrointestinal tract can be severe if the patient tries to eat high-fat foods, however. In this unusual way, doctors say, the drug actually enforces better eating habits.

Beware of sticker shock

None of these drugs are modestly priced, and health-plan coverage varies.

In addition, their usefulness is limited, since they don’t provide “stand-alone” therapy for overweight or obesity. Rather, Meridia, Xenical and Alli are part of a larger weight-management program calling for dietary changes and physical activity to succeed.

In other words, there still are no “magic bullets” for weight control, whether you need to lose 10 pounds or 100. Lasting weight management, doctors say, is still basically the result of changing our attitudes about nutrition and physical activity. But the many benefits—from better health to better looks—make the sacrifices worth it.


© 2014 Dowden Health Media