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The ‘Carb Blocker’ | What Is White Kidney Bean Extract?

The ‘Carb Blocker’ | What Is White Kidney Bean Extract?
Billy Galipeault
Writer and expert7 years ago
View Billy Galipeault's profile

By Myprotein Writer

Billy Galipeault


You may have heard of this supplement before on shows such as Dr. Oz, but for most of us when we hear about a supplement called ‘white kidney bean extract’, the mind wouldn’t even know which category of supplements to classify it with.

Known by its other alias,carb blockers, they become a bit easier to understand. Put simply, carb blockers are exactly what they sound like. By inhibiting the digestion of starchy carbs, white kidney bean extract can cut the amount of carbs absorbed in the intestines by up to 66%.

As I will explain there is more to this phenomenon, so carry on reading to understanding how carb blockers work to see if they will help you with your training and diet.

The Science of Carb Blockers


Before understanding how carb blockers work it’s important to know how a starch is converted into a sugar in your body. This process starts when you consume anything starchy from potatoes, to rice, bread; a digestive enzyme known as amylase starts to break down the starch into sugars in your mouth.

Think about this the next time you eat a slice of white bread, you might notice as it dissolves in your mouth it becomes sweet, this is the amylase breaking the starch of the bread into sugars. But of course this only happens to a small degree in the mouth. After we swallow the remaining starch it is halted in its break down because the sheer acidity of your stomach acid, which prevents amylase from doing its job.

It’s not until the small intestines that your pancreas can secrete more amylase to finish breaking down the rest of the starches into usable glucose for your body.


How Does White Kidney Bean Extract Help?

Lose Weight

Now that we all understand how starches are digested, explaining how carb blockers work will make much more sense.

The active ingredient in white kidney beans which gets extracted is called phaseolus vulgaris, which effectively prevents the pancreas from secreting amylase. If 1.5 grams of the supplement is taken with a carb heavy meal, over half the calories coming from complex, starchy carbs will not get digested and instead will ferment in your intestines. The only side effect most people experience from this process is slight bloating and sometimes excessive gas.

At this point I know what you're probably going to ask, “When I'm on a diet and I decide to have a cheat meal can I take a serving of a carb blocker to lessen the damage?”

While there is no short answer, the long one starts with a possibly. It all depends upon what the cheat meal includes, if your idea of a cheat meal is a lot of rice and potatoes then sure, carb blockers will definitely help. But if you’re like me, and have cheat meals which entail sugary snack food and greasy pizza then most likely carb blockers won’t help you that much.

For you see, carb blockers are exclusive to stopping the breakdown of complex carbs into simple carbs only, leaving any other type of macronutrient digested completely. Which includes sugar from those brownies, saturated fat from that pizza and any other unhealthy food you had which wasn’t a starch (but your ramen noodles will surprisingly be blocked from digesting).

Who Should Use Carb Blockers?

white kidney bean extract


Just like fat burners, carb blockers will only be effective for a certain type of individual. Like all supplements, overweight individuals with unhealthy diets can take a carb blocker, along with taking up an exercise routine and a healthier diet, and will see better results than a placebo group. But it gets a little more complicated when a healthy individual who tracks their calorie intake and macronutrients take a carb blocker to try and lose additional weight.

In the midst of the low carb dieting trend, these are the individuals who will get the least out of carb blockers, if that wasn’t already obvious. If your carbs are below 150 grams a day, you do some form of cardio or weight training more than 4 times a week, then carb blockers will have almost no effect besides making you even more carb depleted and energy deprived. But if your carbs are somewhere closer to the 250-300 gram range and you’re trying to diet down without giving up tasty, precious carbs, then carb blockers might help you lose a little extra weight.

I also shouldn’t have to mention as well that if you’re not in a calorie deficit, or in other words consuming less overall calories than you’re burning, you will not lose weight no matter what supplements you take. To sum up the thoughts laid out in this section, individuals who will get the most out of carb blockers are people new to fitness and have a rather higher body fat percentage. While healthy, fit individuals who know how to maximize a carb blocker will only see maybe a slight advantage to not taking it in the first place.

Take Home Message

In the end, carb blockers are like all other supplements and fat burners out there, they do have some benefit, but only when used correctly and even then only offer a minor benefit. It is also important to note that everybody is different and while one person might see strong results with this product, another with the same body type and weight loss strategies might receive no benefit.

It all comes down to how your body processes carbs and other minor things such as an individual’s insulin sensitivity/metabolism. The take home message here is, if you have the extra money, go ahead! Try a carb blocker out but don’t expect it to do the work for you.

Personally I would still eat in my 500 calorie deficit to lose weight as if I wasn’t taking the supplement, and use it as insurance to keep me in that deficit in case I end up going out to a restaurant and underestimating the calories in a meal for example. Just always keep in mind that your dream body is possible without any supplementation, but since nobody is perfect and can track calories/progress with 100% accuracy, supplements are a convenient way to help you achieve your goals (slightly) easier. Thank you for reading this article, always remember to eat smart, train hard and get your sleep!

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Billy Galipeault
Writer and expert
View Billy Galipeault's profile
Billy is passionate about all things fitness and nutrition, with an emphasis on muscle and strength building. He's currently serving active duty in the air force, while building his body muscle by muscle in his free time.