Carb Blockers – How Do Carb Blocking Supplements Work

Carb blockers are a popular type of weight management supplement that restricts carbohydrate absorption.

Blocking carbohydrates

A gram of carbohydrate provides four calories, but the body has to digest the carbohydrate before it can be utilized and put to work as a source of energy or stored as fat.

By interfering with the body’s ability to do this, carb blockers allow you to eat carbs with less risk of weight gain. That’s the theory, anyway.

What Are Carb Blockers and How Do They Work?

The body uses enzymes to digest food. These enzymes breakdown nutrients into particles that are small enough to be absorbed through the walls of the intestines and enter the blood.

Each nutrient is digested by a specific enzyme. Most carb blockers act on the enzyme that’s responsible for digesting starchy carbohydrate. For this reason, they are also sometimes known as starch blockers. The enzyme they “block” is called alpha-amylase.

Alpha-amylase does not have the ability to breakdown simple sugars, dietary protein or fat. It works exclusively on starchy carbohydrate.

Before going any further, it’s important to point out there are two main types of carbohydrate—simple carbs and complex carbs.

simple carbs and complex carbs

Simple Carbs Vs Complex Carbs

Simple carbs occur naturally in fruits and dairy products. Table sugar is also a simple carb. This type of carbohydrate is not vulnerable to alpha-amylase. Another enzyme has the job of breaking it down.

The body processes simple carbs quite fast so they can be good for providing a quick energy buzz. However, when they provide more energy than the body requires, which is often the case, the extra energy is stored as fat. That’s why candy and cookies are so bad for the waistline.

Complex carbs or “starchy” carbs are the type you obtain by eating oatmeal, bread, rice, pasta, and potatoes. They consist of many simple carbs that are linked to form chains. These chains need to be broken apart before energy can be released.

Due to the fact complex carbs are harder to process, they release their energy more slowly. This makes them good for providing an ongoing supply of energy, but complex carbs can still cause weight gain when eaten without the necessary discretion.

Carbs what are they

Carbs and Cravings

Eating too much carbohydrate, especially simple carbs, can cause high blood sugar. When this happens, the pancreas releases insulin to bring the blood sugar down again. This can cause the blood sugar level to “crash”.

The body responds to a blood sugar crash by triggering cravings for more sugar and carbs. How’s that for a vicious circle?

By blocking carbohydrate absorption, carb blockers may help prevent this scenario from happening.


Carb blockers don’t completely block carbohydrate absorption, they just reduce it. A lot of the calories still get through.

At best, the average carb blocker is only likely to block the activity of 50-65 percent of the carb-digesting enzymes. However, that does not mean carb absorption will be reduced by the same percentage.

In one study, involving a super-potent carb blocker, the ingredient inhibited 97 percent of the enzymes. Yet it only reduced carbohydrate absorption by seven percent. [SOURCE 1]

Mulberry extract blocks carbs

What Ingredients Do Carb Blockers Contain?

Most carb blocking products contain white kidney bean (Phaseolus vulgaris). It’s the ingredient that has the best reputation for inhibiting alpha-amylase. [SOURCE 2]

The hydroxycitric acid (HCA) provided by garcinia cambogia is credited with this ability as well.

Some carb blockers also contain ingredients intended to act on the enzymes that breakdown simple carbs.

Examples of ingredients used for this purpose include:

  • Mulberry extract
  • Hibiscus
  • L-arabinose

Where Does the Blocked Carbohydrate Go?

The blocked carbohydrate passes through the intestines without being broken down or releasing any calories. It then exits the body with the stool.

Again, it’s important to remember the fact that the unblocked carbohydrate will be processed in the normal way.

Potential Side Effects

Although carb blockers are considered safe, using such products still has the potential to cause problems.

When the undigested carbohydrate is fermented by intestinal bacteria it can cause a build up of intestinal gas. Flatulence is the most obvious result of this, but other side effects may include bloating and cramping. Carb blockers also have the potential to cause diarrhea.

Such side effects are generally not severe and tend to lessen with time. However, anyone who is thinking of using this kind of product needs to be aware the potential for such side effects exists.

Additionally, due to the fact that carb blockers can influence blood sugar levels, anyone who has diabetes will need to discuss the matter with a doctor before using carb blocking products.

Additional Benefits

Due to their method of action, carb blockers increase the quantity of resistant starch passing through the intestines.

Although the fermentation of these starches causes gas, the process also releases short-chain fatty acids. These acids nourish the cells of the colon. They may also help offer protection against obesity and certain diseases such as type 2 diabetes. [SOURCE 3]

There is also speculation that carb blockers may help decrease appetite by affecting hunger hormones and slowing stomach emptying after a meal.

Although there is evidence to support these claims, it’s an area that requires more extensive study. When it comes to suppressing appetite, there are certainly better ways to do it. Appetite suppression should be seen as a desirable fringe benefit, at best.

Potential for Abuse

The people who use carb blockers often do so for all the wrong reasons. Instead of incorporating them into a sensible diet, they think of them as cheat pills. A similar problem exists with fat blockers. Both types of supplement are very open to abuse.

A lot of people want to lose weight and/or prevent further weight gain, but love to eat lots of starchy foods like potatoes and pasta. So instead of making sacrifices, they try to use carb blockers to provide damage limitation.

This is wrong thinking, but some supplement manufacturers feed on this desire by advocating the use of their products for “cheat days”. Adopt an attitude like this, and the only one you are cheating is yourself.

The only way to lose weight and make it stay off is to make the necessary lifestyle changes and adopt good eating habits. Carbohydrate is an important part of a healthy diet, but eating excessive amounts is unwise. A healthy balance needs to be maintained. There is no use in trying to use pills to buck the system.

Keto diet

Relationship with the Keto Diet

The ketogenic diet or “keto diet” involves making dietary changes intended to place the body in a state of ketosis.

Ketosis a metabolic process that happens when the body lacks sufficient carbohydrate.

During ketosis, the body switches its source of fuel to the energy-providing ketones it extracts from fats.

Weight loss is just one of may benefits the ketosis diet allegedly provides. It’s becoming very popular. The fact that certain celebrities favor the keto diet helps it to get a level of credibility it may not deserve.

The keto diet involves switching to a low-carb diet and eating more fat and protein.

Some keto dieters try to further decrease their lack of carbohydrate by using carb blockers. However, it’s important to remember it’s possible to reach a state of ketosis without the help of carb blocking supplements.

The keto diet can also present problems. Bad breath is one of the milder negative aspects of keto dieting. Mental confusion and nausea are two more.

There’s a lot of controversy about the keto diet. If you are thinking of switching to this type of lifestyle, with or without carb blockers, it would be wise to get professional medical advice first. [SOURCE 4]

Are Carb Blockers a Good Option?

Some research suggests using carb blockers can help people to lose more weight than they would with diet and exercise alone. That’s the good news. The bad news is, there are also studies that suggest carb blockers don’t work at all.

The thing to remember is, most people who buy this type of product do so for weight-related reasons. Some of them are overweight and are serious about doing something about it. Others love eating high-carb food and are hoping to find a way to keep doing so without paying the price.

The people who incorporate a carb blocker into a regimen of healthy living that involves a calorie-controlled diet may find it helps. If not, their low-calorie diet will ensure they are still making progress anyway.

Let’s not forget, as with fat burners, appetite suppressants, and other weight management aids, carb blockers are meant to supplement existing steps to lose weight. They are not intended to replace them.

Moreover, using carb blockers to try and support an unhealthy love of carbohydrate is a ridiculous idea. Instead of trying to fight against nature, it makes more sense to make the necessary changes and adopt a lifestyle that is conducive to overall good health.

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