Alli is the brand name for tetrahydrolipstatin in the US and is a popular drug used to combat obesity. It is also known as Orlistat and Xenical and is the first diet pill to obtain approval from the Food and Drug Administration and is expected to show enormous profits in the coming years.
Xenical has been shown to be successful in combination with exercise (wow, who would have guessed that doing exercise was good for you). Participants in a study lost more weight using the drug than those taking sugar pills. Although statistically significant, the increased weight loss due to Alli is not particularly large and is therefore no substitute to a healthy diet and exercise regime. Furthermore, when people stop taking the drug they tend to regain between 25-45% of the weight they lost. This is perhaps due to a psychological dependence on the drug and a tendency to rely on its effects too heavily.
The drug inhibits pancreatic triacylglycerol lipase – the enzyme responsible for converting fat into monoglycerides. In addition to promoting weight loss, this also decreases the chance of developing diabetes and heart disease.
Tetrahydrolipstatin is associated with digestive side effects, such as producing excess oils in excrement. The drug has also been known to cause digestive irregularity and in some cases loss of control of the intestine. These side effects can be minimized by following a low-fat diet and usually lessen with time and are manageable with little effect on the patients’ quality of life. In the worst case scenario Xenical can cause kidney damage, due to oxalate being deposited in the kidneys from the stomach.
Keep in mind that despite the FDA approval and the aggressive marketing campaign, Alli is not a miracle drug. The test subjects that took the drug lost only about 5 pounds more per year than those that stuck to regular diet and exercise. Walking 20 minutes more per day and making minor adjustments to your diet can easily compensate for this effect (but it won’t make the drug companies so much money).