Fat blockers do what the name implies: block fat from being absorbed in the intestinal system. The idea is that by blocking the absorption of fat, which has 9 calories per gram, you will decrease the number of calories you're consuming without having to cut down on fat in your diet. This no-brainer approach to losing weight may sound great, but it comes with some unpleasant side effects -- gas, oily and loose stools and incontinence. Chitosan's and alginate's efficacy and safety are explained below.
What is it? Chitosan (pronounced KITE-o-san) is made from chitin, the main component of crustacean shells. It is indigestible, and some say it binds with dietary fats in the intestinal tract, blocking their absorption.
Does it work? Possibly, but the research is conflicting. A few studies have seen a modest weight loss of 1 to 2 pounds with chitosan when compared to a placebo, but other studies have failed to show significant weight loss with its use. Specifically, a study done on healthy individuals showed that taking chitosan did not increase the amount of fat found in their stool, even though chitosan supposedly blocks fat absorption by binding to it so it can be expelled from the body. As with many of the ingredients discussed in this buyer's guide, more research is needed to determine chitosan's effectiveness as a weight loss supplement.
Is chitosan safe? Chitosan is likely safe when used for short periods, but side effects do occur. These mostly include gastrointestinal symptoms such as gas and constipation. If you are allergic to shellfish, do not take chitosan since it is made from the shells of crustaceans. Also, there is some concern that chitosan may increase the effect of blood thinners. If you are on Coumadin (warfarin), Lovenox (enoxaparin) or Plavix (clopidogrel), speak to your healthcare provider if you are considering using a supplement containing chitosan.
What is it? Alginate, also known as algin or alginic acid, is a component of brown algae. When it dissolves in the stomach, it forms a gel-like solid that stays in the stomach for an extended period. It is this action that manufacturers of alginate supplements claim creates a sense of fullness and inhibits fat absorption.
Does it work? The evidence runs the gamut from it really works to total failure for weight loss. While a preliminary study showed mild weight loss of about 6 pounds with the use of alginate compared to a placebo, subsequent studies have shown no significant weight loss or increased sense of satiety with the use of alginate. More research is needed.
Is alginate safe? Alginate is likely safe when consumed in small amounts, but whether the higher doses found in supplements are nontoxic has not been established. Adverse events, or unintended consequences, of alginate are abdominal bloating, heartburn, headache and constipation, and they have all occurred with short-term use. It is unclear what side effects may occur with long-term use. Lastly, alginate can potentially interfere with the absorption of medications. Talk to your healthcare provider before using an alginate supplement.