When diet and exercise just aren't doing the job for whatever reason, there are other options. Some weight-loss medications such as Xenical (orlistat) and Meridia (sibultramine HCI monohydrate) hold promise in treating obesity. In clinical trials, Xenical produced a 5 percent or higher weight loss in 72 percent of subjects over a period of six months. The mean weight loss was 23 pounds. Meridia had similar efficacy, with a 5 percent or higher weight loss in 77 percent of subjects and a mean weight loss of 21 pounds at two years.

In 2007, the FDA approved an over-the-counter version of orlistat, called alli, for commercial sale. The drug is the same as the prescription version, but comes in dosages of half the strength (60 mg versus 120 mg) and is accompanied an online companion behavioral weight-loss program.

The ADA recommends that weight-loss medications only be used in patients with a BMI of 27 or higher, and always in conjunction with lifestyle modifications (i.e., diet and exercise).

Side Effects

Both Xenical and alli can cause considerably unpleasant gastrointestinal side effects, including cramping, diarrhea, gas, and leakage of oily stools. Eating foods with high fat content will worsen the side effects. Meridia can elevate blood pressure and is not recommended for use in anyone with a history of hypertension or cardiovascular disease.