How Does Alli Work?

What Is Alli?

Introduced in 2007 as an over-the-counter alternative to the prescription weight loss medicine Xenical, Alli has quickly taken a foothold in the weight loss market. With claims that you can lose five extra pounds for every ten pounds you would lose with exercise and diet alone, many struggling with obesity have turned to Alli, regardless of its unique side effects.

Enzymes

Whenever you eat a food that contains fat, special digestive enzymes in your body, called lipase, attack the fat and break it down into small enough particles that the body can absorb them. The absorbed fat is then stored for quick access in cases where the body needs additional energy. Unfortunately, this storage can get out of hand when too much fat is consumed, contributing to obesity. Alli works by targeting lipase and disabling it from being able to do its job.

Waste

Without lipase, fat is unable to be broken down into small enough particles to be absorbed. Instead, the fat continues on through the digestive system and is eliminated from the body through your stool. Although Alli is unable to block all fat that enters your digestive tract from being absorbed, it does block enough to help increase your overall weight loss.

Treatment Effects

One of the most well known problems with Alli is what the Alli website refers to as "treatment effects." Since a substantial amount of fat is not broken down in the body while using Alli, the exit of the fat in your feces can result in oily stool. If your intake of fat exceeds 15 grams of fat in a single meal, Alli may not only cause oily stool but may also cause you to lose control of your bowels, leading to an oily accident before you reach a bathroom. According to the Mayo Clinic, as long as you stay below 15 grams of fat, you should be able to avoid most severe treatment effects.

Vitamins

Because many vitamins in your body rely on fat in order to be used by the body, you may need to take a daily vitamin supplement at a separate time from when you take Alli. Fat-soluble vitamins that may be affected by the use of Alli include vitamins, E, D and A.