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Blocked carbs still deliver calories
Dimmer switches
Metabolism runs on dimmer switches rather than on and off ones. Words like block, attenuate, and inhibit mean a dial turned down. Carb blockers such as white kidney bean extract cut carbohydrate digestion somewhat, so blood glucose rises less, yet almost all the calories still arrive, in a different form.
Fermentation
The fermentation happens once carbohydrates reach the large intestine, where bacteria turn them into volatile fatty acids that get reabsorbed into the liver.
The 30-gram protein claim
The same logic undercuts the claim that the gut absorbs no more than 30 grams of protein per meal. Undigested material doesn't simply sit in the gut, and the usual result would be diarrhea. If a 30-gram absorption cap were real, a steak would cause diarrhea every time a meal crossed that threshold.
How do carb blockers work?
Most carb blockers inhibit alpha-amylase, the enzyme that breaks starch into sugars. Phaseolamin from white kidney beans is the best known. A drug called acarbose works on a similar principle, inhibiting alpha-glucosidase at the gut wall. Because undigested starch reaches the colon, side effects of acarbose include gas and bloating.
How much energy do gut bacteria recover?
Bacteria in the colon ferment carbohydrates that escape digestion and produce short-chain fatty acids. In a 1984 paper in Gut, Neil McNeil estimated that these acids supply roughly 6 to 10 percent of the energy needs of people eating a Western diet. The body absorbs them across the colon wall and burns them as fuel.
How completely does the gut absorb protein?
Studies that sample material at the end of the small intestine, called ileal digestibility, find most dietary proteins are 85 to 95 percent absorbed. Protein sources like eggs and milk are near the top of that range. The small intestine has a very large surface area, with villi and microvilli that multiply it many times over.
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