Some weight loss pills can cause serious health problems for individuals, a local doctor has warned.

Khalid Al-Madani, a consultant in clinical nutrition at Advance Clinic, and former vice president of the Saudi Society for Food and Nutrition, said recently obesity-fighting products can be divided into categories approved by the Saudi Ministry of Health, the American Food and Drug Administration and the European Medicines Agency.

The only authorized drug for the treatment of obesity is Orlistat that is sold under the trade name Xenical. Al-Madani said Orlistat works to prevent the absorption of an estimated 30 percent of fats that enter the human body through eating. They have to be taken in capsules three times a day. One common side effect is the passing of oily, yellowish stool.

The other drugs on local markets are not authorized by the health authorities as a main treatment for obesity, with some having serious negative side effects.

Some drugs such as Fluoxetine causes the loss of appetite but is primarily made to fight depression. Another drug, Metformin, effects metabolic processing of carbohydrates, which contributes to weight loss but is mainly used to treat other diseases such as Type II diabetes.

He warned that it is also dangerous to fight obesity using laxatives and diuretics. This is more harmful that obesity itself.

It is also not advisable to use dietary supplements. He said people should avoid non-pharmaceutical products not approved by the Ministry of Health, including chromium, vinegar and laxatives.

Many of these substances contain Chitosan, which is extracted from the shells of shrimp, lobster and crabs. It is a fibrous substance. However, Al-Madani said that a study in the European Journal of Clinical Nutrition published in May 1999, found that the use of Chitosan does not lead to weight loss for people with obesity. This is backed by the American Food and Drug Administration, which stated that no herbal drug is considered safe and effective for the treatment of obesity.

Al-Madani said there is a market for weight-loss pills in the Kingdom because of rising rates of obesity and the increasing awareness of the health risks associated with the condition.