People treated with Xenical and a reduced-calorie diet with no more than 30 percent of calories from fats showed in studies to have achieved significantly greater weight loss than people who were treated with diet alone.
In trials participants on a reduced-calorie diet for 4 weeks, followed by the diet plus Xenical or the diet alone for 52 weeks, lost an average of twice as much weight as those who used the diet alone.

Clear scientific evidence has shown that if you are overweight, losing as little as 5 percent to 10 percent of your body weight can result in improved health. Two-thirds of people treated with Xenical plus diet successfully lost at least 5 percent of their body weight after 2 years.

There are many weight-loss drugs you may have heard about that act in the brain or central nervous system to suppress appetite or to speed up metabolism, but Xenical works in your digestive system to stop about one-third of the fat in the food you eat from being digested. There are enzymes in your digestive system which are called lipases which help digest fat. Taken with meals, Xenical attaches to these lipases and blocks those from breaking down some of the fat eaten. Undigested fat cannot be absorbed and is eliminated in your bowel movements. Working this way, Xenical helps block about one-third of the fat in the foods you eat.

Because Xenical interferes with your body's absorption of some fat-soluble vitamins you should take a daily multivitamin supplement that contains vitamins D, E, and K and beta carotene.

Weight loss and a healthy diet improve a number of weight-related health risks and studies show that weight loss with Xenical can decrease total and LDL cholesterol, the level of low-density lipoprotein-also known as bad cholesterol. This improves the ratio of bad to good cholesterol (LDL/HDL cholesterol). Weight loss can also reduce blood pressure, reduce levels of insulin and reduce the risk or delay the progression to type2 diabetes. The long-term benefits of Orlistat on weight-related illnesses and life expectancy have not been studied.

People treated with Xenical and a reduced-calorie diet with no more than 30 percent of calories from fat achieved significantly greater weight loss than people who were treated with diet alone.