Dieting By “Blocking” Starch And “Blocking” Fat

Vital Information

The idea that starch or fat can be blocked from digestion appears to be an appealing idea. For the past thirty or more years, these products have come to the forefront periodically with promises for a new generation of overweight people. Each time they come on the market, they offer up suggestions that you can eat what you want so long as you take their product. The product, so goes the promise, will protect you from the consequences of eating the blocked food group.

Sigh. It just isn’t so.

Starch Blockers

The advertisement says something like this: “It has already revolutionized weight control programs! You can eat whatever you like and still LOSE WEIGHT! How does it work? It blocks 500 starch calories from your meal by inhibiting the action of the enzyme Alpha Amylase, the body chemical that is supposed to digest starch. The 500 calories of starch pass through you without being digested, while everything else is digested. You’ll be a new person!”

Again, sigh. This is complete nonsense. It was complete nonsense the last time the product was offered up for sale, and it will be complete nonsense the next time, too.

To begin with, how is the product going to block only 500 calories of starch? Or, for that matter, how could it block as much as 500 calories? The product could not measure the calories present, and work its magic until 500 were blocked, and then stop. Calories are not little units of something like ‘pegs’ that can fill 500 ‘holes’ in the starch blocking product. A calorie is a unit of heat, like a degree, that is produced when food is burned to a crisp in a specially designed small oven.

The starch blocker ads claim it blocks the digestion of starches by inhibiting the action of the enzyme amylase, the body chemical that break down starch.How is the pie-in-the-sky product to know how much amylase secreted in your body is required to digest the amount of starch that would produce 500 calories of heat in your body?

But, all this set aside, let’s look at what would happen if a lot of the starches you ate actually did pass through you undigested. If amylase could be deactivated by a pill, it would result in the same situation as if the person were what we might call ‘starch-intolerant.’ (No doubt you know that when people can’t eat milk products because they don’t have enough of the enzyme to digest lactose, we call them ‘lactose-intolerant.’)

Now, remember that starches are actually sugars that are joined together in slightly more complicated bonds than food items we usually think of as sugars. And, remember that there are hosts of beneficial bacteria living in your intestines at all times.

In the absence of starch enzymes in the small (upper area) intestines, the intestinal bacteria in the large intestines (lower area) will break down the starches as best they can to get at the sugars, and since the process would be incomplete, you would develop a belly ache you wouldn’t be forgetting very soon. Your abdomen would swell up like you were eight months pregnant, and you would have intestinal gas a week from Sunday. And after all that, you’d have a great case of diarrhea worth writing home about. Gas formation from eating beans is also a result of undigested starches in the beans.

Actual Studies

And even if all those unpleasant symptoms did not complicate your life, what would be the effect of the blockers? Several studies looking at the effect of starch blockers are in the literature. In one such study, the intestinal tracts of the test subjects were washed out in the way it would be done in preparation for a scope examination of the intestines, using a so-called ‘colonoscopy prep solution.’ This was done several hours after the subjects had eaten either a test meal or a test meal with the starch blocker product. The caloric content of the washouts from each subject was calculated, and guess what? There was no difference in the washout from those eating the meal with the starch blocker compared to the washout from those not eating the starch blocker.

Fat Blockers

In 1993, one Arnold Fox, M.D. touted ‘The Fat Blocker Diet’. This diet suggested that a product known as chitosan was the long-awaited miracle. Chitosan was advertised as a ‘nitrogenous polysaccharide’ product made from the exoskeletons of shellfish. (Exoskeleton means the shells of such sea creatures as shrimp and lobsters.) Supposedly chitosan would “soak up fat like a sponge,” then “smoothly biodegrade,” that is the chitosan would breakdown without problems.

My first question is, “What else will chitosan soak up like a sponge?” It is unlikely that it prefers fats above all else. Will it soak up proteins, vitamins, minerals? In reality, I haven’t seen any evidence that chitosan can actually soak up dietary fat. Fats do come in various forms and types, after all. But even if it works, is soaking up dietary fat such a good idea? Remember that fats are absolutely required for life. They are not the devil. And while it is true that most undigested dietary fat will not provide dietary calories, it is equally true that if fat is not digested, most of the fat-soluble vitamins A, D, E, and K, most of the calcium, and most of the essential fatty acids will
be lost.

And there’s another wrinkle: unlike carbohydrates and proteins which must be fully digested before they can be absorbed, not all fats need to be fully digested before they can be absorbed into the body. Some dietary fats enter the lymphatic system directly without being digested. (The lymphatic system can be thought of as a secondary blood system, not involved with carrying oxygen.) So losing weight by avoiding fat calories in this way doesn’t work very well either.

Lipase Inhibitors

More recently, some drugs, notably Orlistat and Xenical have come under study. These drugs inhibit intestinal lipase, the enzyme that breaks down fat so that it can be absorbed through the walls of the gastrointestinal tract. Inhibition of lipase causes some of the dietary fat to continue down the intestinal tract without being digested. This usually results in many gastrointestinal side effects including abdominal pain, fecal incontinence (inability to control the bowels), liquid or oily feces, nausea, and vomiting. Additionally, studies show that blood levels of vitamin A, E, and D are decreased in patients taking the drugs.

One would assume that low dosages of the drugs would result in lower levels of side effects, and this is true, but low dosages of the drugs do not result in weight loss. High levels of the drugs are required, and the higher the level of dosage, the more the side effects.

So, boys and girls. You might think twice or three times before trying to block starches and fats once they are in your body. Block starches by not eating them in the first place, and leave fats alone to benefit your body. Next time, we’ll go on to a few more subjects in this History of Diets and Dieting.