Glucomannan and weight loss: all the benefits listed!

Glucomannan, chances are you’ve never heard of this substance before. If you want to lose a few pounds, you really should! Glucomannan is a natural dietary fibre derived from the Konjac plant. No, it has nothing to do with alcohol. What’s even more interesting is that glucomannan is known to be an effective aid during dieting. In fact, even the Netherlands Food and Consumer Product Safety Authority has recognised that Glucomannan, in the context of a calorie-restricted diet, can contribute to weight loss! And that’s not the only benefit, as glucomannan also helps maintain normal cholesterol levels in the blood. Sounds too good to be true? Then read on!

What exactly is Glucomannan?

As mentioned above, glucomannan is a fibre derived from the root of the Konjac plant. More specifically, glucomannan is a water-soluble dietary fibre with an enormous capacity to absorb water, up to 50 times its own weight! In tests where glucomannan was placed in a glass of water, the entire contents of the glass turned into a gel with high viscosity. This is exactly what makes glucomannan so unique compared to other dietary fibres. It may contain the same amount of kilocalories, but because it absorbs so much water, it creates a significant amount of stomach filling for only about 20 kilocalories. The fact that glucomannan attracts so much liquid is precisely why it works so well in combination with a calorie-restricted diet: by filling your stomach, it creates a better sense of fullness, making you less likely to overeat after consuming it (and as you may know, preventing hunger is the key to any successful diet). A common strategy is to take glucomannan 30 to 15 minutes before a meal. This reduces the chances of overeating during the meal—especially useful if you have a big dinner planned with an abundance of food. It helps you keep things under control. Because of the fullness glucomannan creates, it also takes longer for your body to process the food in your stomach, which contributes to a longer feeling of satiety. As always, this is the theory, so let’s see if scientific research supports it!

Glucomannan and weight loss

In 2005, a study [1] was conducted in which researchers wanted to test whether supplementation with various dietary fibres was more effective for weight loss compared to a placebo. The study involved 175 men and women, using both glucomannan alone and combinations of glucomannan with other fibres. The participants were overweight and were put on a 1200-calorie diet, supplemented either with a fibre supplement or a placebo.

After a period of 5 weeks, the researchers found that the group taking a fibre supplement had lost about 1.5 to 2 kg more body weight compared to the group taking a placebo. There was no significant difference between the groups using different fibres, suggesting that glucomannan is the key fibre in this regard. This difference may seem small, but it’s important to realise that we’re looking at just a 5-week period. For people with overweight or even obesity, a much longer journey is usually required to return to a healthy weight. If we consider a period of 20 weeks or more, this difference from taking glucomannan could already be 6 to 8 kg! It's also important to mention that all these findings were statistically significant, meaning the likelihood of this happening by chance is minimal (<1%). Therefore, the theory that glucomannan increases the feeling of fullness and supports weight loss during a calorie-restricted diet has solid scientific backing.

Glucomannan and your cholesterol

In addition to the benefits mentioned above, glucomannan is also good for cholesterol levels, which is especially interesting for people with cholesterol issues. The theory behind this is that glucomannan hinders cholesterol absorption in the intestines, improving your blood values. A 2008 study [2] tested this theory and found that total cholesterol, LDL cholesterol (the ‘bad’ kind), and free triglycerides decreased with glucomannan supplementation. Weight loss was also observed in this study, further supporting the findings of the first study. Whether glucomannan benefits cholesterol levels solely by impairing absorption or also by supporting weight loss is not entirely clear. It’s likely a combination of both, leading to overall improved health for the participants. Either way, these are very interesting effects that make glucomannan well worth considering.