Most diet pills, especially those sold over the counter, work by increasing metabolism and decreasing appetite. The products often contain one or more of these ingredients: ephedrine (also known as ma Huang and ephedra), guarana and caffeine, all of which increase metabolism. They also increase heart rate and blood pressure and, if taken in excess, can cause heart attack and stroke. Products containing ephedrine are especially dangerous and can no longer be sold legally in the United States.
Other diet pills available by prescription only, such as Meridia, phentermine and dextroamphetamine, can also cause problems for people with high blood pressure. The only product that will not is Xenical (also known as orlistat). Xenical works by blocking fat absorption in the gastrointestinal tract. It does not increase metabolism or decrease appetite. Unfortunately about one out of every four people will have gastrointestinal side effects including diarrhea, oily stool, intestinal gas and the like, which make the drug a bit difficult to tolerate. Like any diet pill, Xenical will not provide long-term weight loss. It only works for as long as you are taking it.
To achieve more sustained weight loss, calorie restriction and exercise are mandatory. Diet pills can help get the ball rolling, but should only be used in combination with a weight reduction program that includes lifestyle changes.
