Originally designed to help control diabetes, carb blockers, also called starch blockers, theoretically work by preventing an enzyme commonly found in saliva from breaking down starches as they are consumed. Because the starches are not broken down for digestion, they were thought to pass through the body rather than being digested and absorbed. They are often marketed to people trying to lose weight, but more research is needed to support their effectiveness.
Carb or starch blockers are formulated from compounds called amylase inhibitors that prevent the enzyme amylase from binding with and breaking down carbohydrates in the digestive tract. These inhibitors are derived from plants in the legume family, usually white kidney beans. Other amylase inhibitors are derived from wheat.
Carb blockers have been used for obesity and diabetes control. While studies conducted in the 1980s concluded that carb blockers may be beneficial in treating diabetes, no human studies exist to conclusively support their use for either condition. Because supplements are not regulated by the Food and Drug Administration, you can buy carb blockers over-the-counter.
A study published in the 1998 issue of “Pancreas” found that while amylase inhibitors delayed carbohydrate absorption, the overall effect on carbohydrate absorption was minimal. However, the inhibitors did produce a reduction in blood glucose concentrations after meals. Therefore, researchers concluded that carb blockers may be useful in controlling diabetes. A more recent study, published in the 2007 "International Journal of Medical Sciences," participants consumed either a placebo or a carb blocker, Phaseolus vulgaris. After 30 days of a high-carb diet and the supplement, those who had taken the carb blocker showed significantly greater weight loss, improved body mass index, reduction in waist, thigh and hip circumference and overall fat mass. No studies exist investigating the long-term effects of using a carb blocker.
Because carb blockers may delay digestion of carbohydrates, they are delivered undigested to your colon where they are broken down by bacteria. Hydrogen, carbon dioxide and, in some cases, methane are the by-products of this process. You may experience excess gas, bloating or diarrhea.
Warnings and Precautions
The safety of carb blockers has not been established for children, pregnant and nursing women or those with liver or kidney disease, according to New York University Langone Medical Center. Speak to your doctor before using a carb blocker or any other weight loss product.