What are fat blockers?

Fat blockers commonly contain chitosan, calcium-rich source, which is similar to dietary fiber, but is derived from the exoskeletons of shellfish. Like fiber, they pass through the digestive tract without being digested, but it also purportedly absorbs between 6 and 10 times its weight in fat along the way, all of which is then eliminated in the stool.

How Do Fat Blockers Work

Fat blockers work by binding to the fats in your digestive system and creating a combined substance large enough that it will not travel through the walls of your gut into the bloodstream. When taking a fat blocker, only minimal amounts of fat pass from your digestive tract. The beauty of these drugs is that the user does not need to cut fatty foods from their diet.

When passing through the digestive system, fat blockers can absorb 6 to 10 times their own weight of fats. Once attached to the fat, the blockers simply pass through your system and take the excess fats with them.

When taken before or during a meal, chitosan binds to dietary fats before they can be digested and absorbed into the body. Chitosan allows dietary fat to comfortably pass through the body unabsorbed.

There's a drug treatment to treat obesity which works in a similar way, in that it prevents fat from being taken in to the body. Orlistat (trade name Xenical) inhibits an enzyme in the intestines called lipase which normally breaks fat up ready for digestion. Since the fat isn't properly digested, it isn't absorbed into the body.

Although with Xenical - the drug, and chitosan - the supplement, the end result, blocking the absorption of fat, is the same, the two substances are quite different in the mechanisms by which they attempt to achieve that end.

Orlistat (Xenical) operates strictly in the digestive tract. Rather than acting directly to stop fat from leaving the intestine, it acts as a lipase inhibitor. It prevents enzymes (lipase) in the gastrointestinal tract from breaking dietary fats down into a molecular size small enough to pass through the tiny holes in the intestinal lining. Even the most optimistic studies have predicted Orlistat can act to prevent only about 30% of dietary fat from being absorbed. The recommended dose of Orlistat is one 120 mg capsule with each main meal that includes fat.

Chitosan is a substance extracted from shellfish and has a "balling up" effect on oils it comes in contact with. When you put chitosan in the digestive tract, it doesn't affect enzymes as Orlistat, but rather attracts fat molecules and blobs them up into such large "fat balls" they can't be absorbed. Different mechanism, same effect.

When should you take them?

Both types of blockers are supposed to be taken right before meals in order to effectively prevent the absorption of fat, and lead to weight loss.

Since most fast foods and convenience foods are laden with carbs and fat, dieters and healthy eaters avoid them. But when they're the only option, a Fat Blocker is the best way to minimize the negative impact of those foods.

Fat Blocker Products

Both prescription and non-prescription fat blockers are found on the market. Xenical is the major prescription drug, but there are plenty of non-prescription pills to be found.

- Trimspa
- Xenical
- Chitosan
- Cortipren
- Cortislim
- Zantrex

Do they have side effects?

Because of the way that fat blockers work in your digestive tract, they can sometimes cause cramping, diarrhea and gas. This tends to pass the longer you take the pill, as your system becomes better adjusted it. It is also important to take multivitamins with a fat blocker, since some vitamins - such as A, D, E, F, and K - are fat soluble - that means they're carried in to the bloodstream with fat as it's absorbed - if you block fat, you block these vitamins and the long-term use of fat blockers can lead to vitamin deficiencies. Those vitamins play a major role in metabolism, immune function, and overall health. In addition, some "good fats" that are essential for overall health, such as omega-3 and omega-6 fatty acids, are also blocked in the process.

Fat blockers are a more recent development than appetite suppressant. They are the diet industry's answer to the problem with Fenfluramine, Phentermine and other substances that can sometimes have unwanted side effects such as heart valve damage. Fat blockers tend to have fewer and less serious side effects than appetite suppressants. You should still be on guard however, as even taking fat blockers can have some unwanted consequences (Note: I have not heard of any side effects from using one (1) 500 mg chitosan capsule prior to infrequent "cheat" meals).

Studies show that over a year of use Xenical, there was on average a weight loss of ten per cent of original body weight. There's a risk of similar problems to those with fat blockers, although vitamin deficiency hasn't proved to be a problem in practice.

Most importantly - Are they effective?

While there may be scientific data on how much fat is passed out, there's much less to show whether this effect really translates into weight loss. The first challenge here lies in the fact that such a recommendation will encourage users to consume high fat foods believing the fat will not be absorbed (remember not all the fat is eliminated!). For example, it may be that taking the products simply makes you much more relaxed about what you eat and so likely to eat more fatty products than ever. So there's no guarantee that you'll lose weight.