Alli clinical studies showed moderate weight loss efficacy

Orlistat, known by the brand name Alli, works by decreasing the amount of fat absorbed by the body. It is the OTC version of Xenical, a prescription weight loss pill. The good news: Orlistat has been tested and the prescription version has been used since 1999.

Last fall Dr. James Anderson, head of the UK College of Medicine Metabolic Research Group, and his colleagues examined the effects of OTC strength (60 mg) orlistat on mildly to moderately overweight individuals. The study was the first of its kind. Previously, the slimming pill's effects had only been studied in obese individuals. Study participants took either orlistat or a placebo three times daily with meals for 16 weeks. Results of that study showed those taking OTC-strength orlistat did lose more weight than those taking the placebo.

"Our research showed that people taking orlistat and following low-fat diets lost almost five percent of their initial body weight, about seven to15 pounds, over four months," Anderson said. "While two to four pounds a month isn't dramatic, steady weight loss of this amount can have major health benefits. For example, the reduction in LDL-cholesterol, the bad-guy cholesterol, of 10 percent can reduce risk of heart attack by 20 percent."

Any successful dieter knows that long-term weight loss is about lifestyle changes not quick fixes. While taking Alli slimming pill may help you lose weight, it won't do all of the work for you. Anderson stresses a healthy diet and exercise plan are absolutely necessary to lose the weight and keep it off.

"This is the first over-the-counter slimming pill that has proven effectiveness. It is my hope that people will take one capsule before each regular meal, breakfast, lunch, and supper, and alter their fat and calorie intake," Anderson said. "If they commit to exercise six days a week, most people can lose weight steadily. All of us are in this for the long haul and need to keep up healthy behaviors, not for days or weeks, but for months and years. Doing regular physical activity and making good food choices will help us be trimmer and give us more energy."

Read also Best weight loss pills