There are many weight loss pills available on the market. But, only a portion of those pills have met with the Federal Drug Administration's approval. An examination of the pros and cons of FDA approved diet aids is the first step to understanding if they are right for you.

What FDA Approval Means

Having FDA approval means the Federal Drug Administration believes a drug has been proven safe. A drug gains this approval through many tests and trials. By the time the approved drug becomes available to the public, it has already been taken by thousands of people over a time span of several years. They have all proven that they can trigger or support weight loss without serious apparent health risk.

Diet pills with FDA approval fit into one of two categories. They are either fat blockers or appetite suppressants. However, even with FDA approval, diet drugs are not miracle cures, nor are they without undesirable side affects.

Fat Blockers

Alli is the only over the counter FDA approved weight loss drug. It, and its prescription strength sister Xenical, are both derivative of a fat blocker called Orlistat. Fat blockers work by binding with the fat in the food you eat and preventing the body from absorbing it.

• Pro: Studies show Alli and Xenical work. In one-year clinical trials, between 35.5% and 54.8% of subjects achieved a 5% or greater decrease in body mass. Between 16.4% and 24.8% achieved at least a 10% decrease in body mass. You are allowed to eat fatty foods while taking these fat blockers, however as the drug is shown to only remove about 25% of consumed fat from your digestive system; the more fat you eat the less effective the drug. Populations using the drug also showed slight decrease in tendencies toward type 2 diabetes and high blood pressure.
• Con: Even FDA approved fat blockers have side affects. Since the bound fat leaves through your digestive system, it can cause oily stools, gas, intestinal discomfort and fecal incontinence. These effects worsen with the more fat consumed. Also, Orlistat can prevent your body from absorbing certain fat soluble nutrients.

Appetite Suppressants

Most FDA approved weight-loss drugs are appetite suppressants. Most of those appetite suppressants, such as Adipex-P, Oby-Trim and Zantryl, contain a drug called Phentermine. Phentermine stimulates the neurons in the brain to trigger a fight-or-flight response that shuts off hunger signals.

• Pros: Phentermine is a well tolerated drug. Though man side affects are possible, ranging from nausea to rapid heart, they are usually mild. Phentermine has been proven an effective weight loss pill, especially for short term weight loss.
• Cons: Phentermine is classified as a mildly addictive drug due to it's similarities to amphetamines. Users often develop a tolerance to the drug, diminishing it's efficacy. It cannot be relied upon for long periods of time and is only available by prescription.

The most important part of choosing a weight loss drug is to choose one under the guidance of your doctor. Sometimes even FDA approved drugs can have dangerous effects if taken by the wrong person. The best way to lose weight is still by healthy eating and frequent exercise. Talk to your doctor to see if weight loss drugs are a necessary option for you.