Glucomannan – A Weight Loss Supplement That Actually Works?

Glucomannan Weight LossLet me explain my position on weight loss supplements.

My opinion is that most of them are scams.

The only way they can help you lose weight is by making your wallet a bit lighter.

That being said…

Some of them work. Most don’t, but some do.

The reason I know, is because I’ve gone to the literature and found actual scientific studies that test them.

None of the supplements I’ve looked at do anything magical.

At best, they provide a marginal effect.

Without a decent diet and exercise program, they will be next to worthless.

But out of the few supplements that I have looked at, the one I am going to talk about today provides the strongest effect.

It is called Glucomannan and is a type of soluble fiber. You know, like the stuff you find in vegetables and nutritionists tell you that is good for you.

Except this one is special.

It’s a rather unique type of fiber that you don’t find much of in the western diet.

You may have heard of it before and you may have seen it in some weight loss supplement formulations.

Glucomannan and Weight Loss

Let me explain how glucomannan works.

It is a soluble fiber, which means that humans don’t have the enzymes to break it down and use it for fuel.

In the stomach and intestine, it absorbs water, kind of like a sponge, and gives you a feeling of fullness.

It also slows absorption of other nutrients, reducing the rapid spike in blood sugar that tends to happen after (carb-heavy) meals.

The combined effect of inreased fullness and slowed absorption of nutrients helps decrease appetite level and cause an automatic reduction in food intake.

What soluble fibers also do (including glucomannan) is to travel to the large intestine, where it becomes food for the healthy bacteria.

The healthy bacteria break it down, use it for fuel and turn some of it into short-chain fatty acids like butyrate, which also have powerful health benefits and can speed up the metabolic rate.

Does Glucomannan Work?

Many things look good on paper and work “in theory,” but when you put them to practice they are basically worthless.

Well, not with glucomannan.

Let me explain.

A study was performed in 20 obese individuals. They were instructed to take either a glucomannan supplement or placebo (1).

The glucomannan group took 1g of glucomannan, three times per day, 1 hour before each meal.

They lost 5.5lbs (2,5kg) in a period of 8 weeks.

Another study with 200 overweight or obese individuals found that glucomannan led to weight loss of 12 pounds (4,5kg) in a period of 16 weeks (2).

Maybe I should also point out that both groups drastically reduced their LDL (“bad”) cholesterol and their triglycerides.

Big deal?

Well, you be the judge. Take another look at the numbers.

5.5lbs in 8 weeks… 12 pounds in 16 weeks…

These are 69% and 75% of the 1 lb/week weight loss generally recommended by most dietitians.

Just by taking a capsule or two of a natural fiber supplement one hour before each meal that also provides health benefits.

There are also some studies showing that Glucomannan can significantly help with constipation. Makes sense, since it is a soluble fiber that absorbs water, makes your stool “bulkier” and makes your food travel faster through the intestine (3, 4).


If you’re already getting results with your routine then you do not need to take this.

But if you’re stalling, have experienced a weight loss plateau… then maybe, just maybe it can give you what you need to start losing weight again.

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  1. Every little helps, as they say. Might give it a try if I can get it, as I have stalled a bit. Thanks kris, this info came at the right time for me.

  2. It is recommended by some to take some sort of fibre supplement on this diet, I’ve been taking Holford’s Carboslow formula. I think that’s what its called, but I will have to check and see what kind of fibre it has in it. Will try this as I’m almost out of the Holford stuff!

  3. Hi Kris. Do you know if you can buy Glucomannan here in Iceland? And since it’s derived from Konjac Root, is it maybe even better to take the diet supplement Konjac?

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