Carb blockers, also known as starch blockers, are a type of dietary supplement designed to prevent the body’s ability to absorb and digest carbohydrates. They’re derived primarily from food-based sources and consist of compounds that interact with digestive enzymes involved in the breakdown of carbohydrates.
While their primary use is to block carbohydrate digestion and absorption, they may also offer other health benefits, such as helping with weight loss and blood sugar management.
Let’s talk more about the benefits of carb blockers, how they work, who should consider taking them, and any risks associated with these supplements.
How They Work
Carb blocker supplements work by inhibiting specific carbohydrates from being absorbed into your body. There are 2 broad categories that carbohydrates fall into: simple and complex. Simple carbs include sugars, such as fructose and glucose. Complex carbs, on the other hand, include starches and dietary fiber.
The starch in complex carbohydrates is what we are looking at when it comes to carb blockers. Normally, this starch is broken down into simple sugars and then absorbed into the bloodstream.
But carb blockers contain compounds that bind and inhibit the enzymes – specifically alpha-amylase and alpha-glucosidase — responsible for the breakdown of complex carbs and the starches associated with them. As a result, a portion of these carbs pass through the gastrointestinal tract undigested and do not contribute to your blood sugar or caloric intake.
The magic key ingredient making this happen? Most of the time, it’s white kidney beans.
White kidney beans, also known as Phaseolus vulgaris, are the primary ingredient in carb block supplements due to a unique compound called phaseolamin. This compound specifically targets the alpha-amylase enzymes, which naturally prevent complex carb absorption.
White kidney bean extract (WKBE) is one of the most researched sources of carb blockers, thanks to its potential to help with weight management and blood sugar control.
While other ingredients may be added, such as green tea or chromium, white kidney bean extract remains the most common due to its proven effectiveness.
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Benefits and Effectiveness
A number of studies have been done on carb blockers and their effects on weight loss, glycemic control, and satiety.
1. Weight Loss
One study followed 60 slightly overweight volunteers taking either a white kidney bean extract dietary supplement or a placebo for 30 days while eating a regular diet.
The results showed that the participants taking who took the carb blocker supplement had more significant decreases in body weight, BMI, fat mass, and body measurements (e.g. waist, hips, thighs). These results occurred while participants maintained their lean body mass, compared to those on a placebo. (1)
A different research analysis showed a positive trend toward weight loss and decreased triglyceride levels in participants using “Phase 2,” another extract from the white kidney bean. Over 8 weeks, those taking Phase 2 lost an average of 3.79 lbs and experienced a significant reduction in triglycerides compared to the placebo group. (2)
So, do carb blockers contribute to weight loss? Various studies have found that a starch blocker with white bean extract as the main ingredient may provide an extra tool – besides diet and exercise – to help manage your weight.
2. Blood Sugar Management
A lab study using proteins from black beans to create unique proteins called “bioactive peptides” showed that these peptides significantly slowed down 3 enzymes tied directly to blood sugar control. (3) This suggests that these black bean proteins could help manage diabetes while blocking the digestion of carbohydrates.
In another study, a potent amylase inhibitor enhanced the malabsorption of wheat starch. (4) When adding this inhibitor to a meal, more starch was able to pass through the colon undigested instead of being broken down and absorbed into the small intestine.
Since starch that isn’t digested in the small intestine generally won’t impact rising blood sugar levels, this blocker could prove to be beneficial for those who have diabetes or are trying to manage their blood sugar.
3. Improved Satiety
A study conducted over 12 weeks, involving 60 slightly overweight but otherwise healthy individuals, explored the impacts of the carb blocker, Beanblock. While there were positive results regarding weight loss, it was also found that the group reported lowered oxidative stress levels, an increase in satiety (the feeling of fullness), and better appetite control. (5)
If you’re following a low-carb diet while also taking a supplement that helps to block carbs, these results may be even more pronounced. (6)
Potential Risks
While carb blockers are generally safe for healthy adults to take, there are some considerations you should take into account. If you try them, always take a starch blocker from a reputable brand, follow exact usage instructions, and check in with your doctor or healthcare provider before taking this dietary supplement if you have any underlying medical conditions or concerns.
Some of the risks associated with carb blockers include:
- Minor digestive discomfort: Carb blockers can cause undigested starch to pass into the large intestine, where it then ferments and may lead to temporary side effects like gas, bloating, and changes in bowel movements. These effects usually go away as the body adjusts to the blocker, but people with digestive disorders, like Irritable Bowel Syndrome (IBS) or Crohn’s disease, may experience worsened symptoms.
- Effects on blood sugar: Carb blockers slow complex carbohydrate digestion, which can help better control blood sugar levels. However, it may also require adjustments to diabetes medications to prevent hypoglycemia (low blood sugar). Anyone on diabetes medication should use caution and consult their doctor, as carb blockers can enhance the effects of their medications.
- Allergic reactions: Most carb blockers are sourced from white kidney beans. If you have a known allergy to this type of bean, avoid any carb blockers with them as the main ingredient or in extract form.
There’s not a ton of information on carb blockers specifically for pregnant and breastfeeding women. That being said, you’ll want to check in with your healthcare practitioner if you fall into this category and are thinking about taking any carb-blocking supplements.
The Takeaway
Carb blockers, particularly those containing white kidney bean extract, have promise for being a great addition to traditional weight loss and glycemic control strategies. That being said, starch blockers may not be the perfect fit for everyone, especially if you have underlying digestive issues like IBS.
As with any supplement, it’s important to consult with your doctor to determine if it’s the right fit for you and your specific wellness journey. We recommend always using it alongside a healthy, balanced diet and regular physical exercise.
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FAQ
When should I take a carb blocker?
Typically 10-15 minutes before you eat a meal is the ideal time to take a carb blocker. This allows time for the supplement to dissolve in your gut and helps to maximize the supplement’s effects.
Are carb blockers suitable for people following a ketogenic diet?
Carb blockers are actually a great tool for many people just starting out on a ketogenic diet, as they help curve carb cravings, increase satiety, and even help promote a better state of ketosis. This can help you stay within your daily carb and macro goals a lot easier. If you’re unsure what your daily target macro goal is, use our free Keto Macros Calculator.
Are carb blockers safe for long-term use?
More research is needed to determine the long-term effects of carb blockers on the human body and overall wellness. However, the studies we reviewed all confirmed that a potent amylase inhibitor can impair starch absorption, with no significant side effects from regular consumption of carb blockers. (5, 2)