If you are thinking about taking medications to lose weight, your doctor should consider 3 questions:

  • Is there a cause of your obesity?
  • Are there any medical complications resulting from your obesity?
  • What is the proposed treatment plan?

Medications should be used in combination with diet and exercise and never as the single method for treating obesity.

Currently, there is only one medication available in Canada for obesity.

Orlistat (Xenical®) is a medication that reduces the amount of fat your body absorbs from the foods you eat. When we eat something containing fat, enzymes help break it down and be absorbed by our bodies. Orlistat stops some of these enzymes from breaking down fat. The result is that about one third of the fat you eat is not absorbed.

Studies show that people who use orlistat for one year, along with exercising and changing their diet, lose about 2.9 kg more than people who do not take the medication. People are 21% more likely to lose 5% of their body weight, and 12% more likely to lose 10% of their body weight, if they use the medication.

If you eat a lot of fat when you are on orlistat, you are more likely to experience side effects from the medication. These include oily spots on undergarments, liquid stools, bloating, gas, stomach cramping, and diarrhea with an urgent need to use the washroom. These unpleasant effects will encourage you to reduce the amount of fat you eat. Orlistat is not recommended for people with certain stomach and liver conditions. If you miss a meal or eat a meal without fat, you need not take that dose of orlistat. Otherwise, the medication should be taken during or immediately following main meals 3 times a day.

Because your body absorbs less fat from your diet when you take orlistat, many doctors also advise that you take a multivitamin supplement containing sources of fat-soluble vitamins (vitamins A, D, E, and K) and beta-carotene. These vitamins are important for your health. Be sure not to take the multivitamin supplement within 2 hours of an orlistat dose. If you are unsure about how to make this timing work, ask your doctor or pharmacist for help.

Perhaps most importantly, one third of people will not respond to medication. Talk with your doctor before stopping or starting any new medications for weight reduction. And, most importantly, remember that using a medication is only one part of an effective plan for losing weight.