Starch blockers inhibit the digestion of carbohydrate. The theory is that if you can’t digest it you can’t gain weight. But having a whole lot of undigested carbohydrate in the digestive tract is bad news. It feeds the wrong kind of bugs, causing bacterial and yeast infections as well as terrible gas. Much touted as an answer to weight loss is a supplement called chitosan, sometimes called the fat attractor or fat magnet, which inhibits the digestion of fat. It apparently works because it has a positive charge and attracts fats, which have a negative charge. Once bound together with chitosan, the fat is less likely to be absorbed and passes through the body, so it is claimed, and cholesterol levels decrease. However, three studies have found no significant differences in either weight or cholesterol levels in people taking chitosan or a placebo. One study involved 30 overweight people who took chitosan or a placebo for 28 days while eating their normal diet.
(1) There was no difference in weight or cholesterol. The second study involving 51 obese women found that the chitosan group had slightly greater cholesterol reduction than the placebo group, but no difference in weight loss after eight weeks.
(2) Another study, with 68 obese men and women, found no improvement in weight or cholesterol.
(3) The latest fat blocker to hit the market is a patented fibre extract from the prickly pear (Opuntia ficus indica) called NeOpuntia®.
While some studies do show that it binds to fat, and also lowers cholesterol, I’ve not been able to find any evidence to date that it causes weight loss. Drug companies are also cashing in on the weight-loss market with drugs that stop you from digesting fat. An example is Xenical, the drug name for a chemical called orlistat. This drug appears to work by reducing fat absorption. However, a recent study found that the drug versus placebo had no beneficial effect on weight loss or liver function in patients with fatty liver disease. The immediate potential side effects are oily spotting, gas with discharge, oily or fatty stools, oily discharge and an inability to control bowel movements. If that doesn’t put you off, more worrying are the effects on essential fats, so vital for heart, brain and skin. Since essential fats are probably the most commonly deficient nutrient in the West, the last thing you want is to swallow something that stops you from using the little there is in your diet.
Also, it probably isn’t a good idea to have undigested fat in your digestive tract. Some slimming drugs are basically stimulants that suppress appetite and wire you up, inducing anxiety and hyperactivity. Similarly, if you drink 15 cups of coffee a day, it would also work in the short term. In the not-so-long term, stimulants mess up your body’s metabolism as well as your physical, mental and emotional health. Even if it sounds ‘natural’, avoid any herb or supplement whose active ingredient is caffeine – and that includes guarana. 1.M. H. Pitler et al, ‘Randomized, Double-Blind Trial of Chitosan for Body Weight Reduction’, European Journal of Clinical Nutrition, vol. 53,1999, pp. 379–81 2. E. Wuolijoki et al, ‘Decrease in Serum LDL Cholesterol with Microcrystalline Chitosan’, Methods and Findings in Experimental and Clinical Pharmacology, vol. 21(5),1999, pp. 357–61. 3. S. C. Ho et al, ‘In the Absence of Dietary Surveillance, Chitosan does not Reduce Plasma Lipids or Obesity in Hypercholesterolaemic Obese Asian Subjects’, Singapore Medical Journal, vol. 42, 2001, pp. 6–10