SIBO and Weight Gain: Does Sibo Cause Weight Gain?

SIBO and Weight Gain: Does Sibo Cause Weight Gain?
(Last Updated On: April 29, 2020)

Small Intestinal Bacterial Overgrowth is also known as SIBO. With SIBO the bacteria from your large intestine have started to migrate into your small intestine. This can leave you with multiple symptoms like bloating, diarrhea, abdominal pain, and nutritional deficiencies. If you want to read more about SIBO, check out the article I wrote about it. But now I’d like to focus on one specific question. Does SIBO cause weight gain?

SIBO and Weight Gain?

SIBO Weight gain

SIBO has 2 types that can be taken into account. And both these types can have a different effect on the body. The H2-producing (hydrogen) SIBO and CH4-producing (methane).
Both of these can be clinically tested with breath tests. And in general, the CH4-producing type causes constipation and the H2-producing type does not.

A study in adults tried to find a link between SIBO and body weight. In that study, the people with H2-producing SIBO generally had a lower body weight than the people without SIBO. Their conclusion is that H2-producing SIBO is not leading to obesity.
In the article describing the study, they do mention that CH4-producing SIBO (with constipation) has been related to weight gain in other studies. But these findings have not been consistent and need to be researched more.

Multiple other studies have found SIBO to be about 2x more common in people who have obesity. This does not prove that the SIBO causes obesity, but does show a link between the two. The question remaining, what came first? SIBO or obesity? Most researchers seem to expect obesity first, SIBO after. If you want to read more about imbalances in the gut and weight gain, check my article.

SIBO is related to malabsorption and maldigestion. This means that the food you eat isn’t being digested properly. You won’t absorb as many nutrients from the food you eat if you have SIBO, in comparison to someone who doesn’t have SIBO. This is because the bacteria are eating with you. SIBO is therefore mostly related to weight loss and malnutrition.
On the other hand, if you would start eating more because you feel like you’re not getting enough nutrients from the food that you’re eating. You could end up eating too much for your energy usage, and thus gain weight. In this case, the SIBO isn’t necessarily the cause of the weight gain. But it does promote a feeling of inadequate intake which stimulates higher food intake and results in weight gain.

Are you having difficulties with weight gain or the management of SIBO? Would you like guidance from a specialized dietitian? Schedule an online consultation at my online dietitian practice Darm diëtist, and I will help you with all your questions!

Conclusion: SIBO and Body Weight

As you can read above, there is not a strong YES or NO answer to this question. A lot of research is still being done on SIBO and it’s relation to body weight and health. In general, SIBO is more likely to lead to weight loss, than to weight gain.

SIBO is interfering with your body’s ability to digest and absorb food. Which leads to a higher risk of nutritional deficiencies and malnutrition. Usually, this leads to weight loss. But, if your body is giving you signs to eat more, because of the nutritional deficiencies, weight gain is definitely not out of the question. So ask yourself, have my food patterns changed? Am I eating differently? More energy dense? Bigger portions than before? There may be some answers there for you. But don’t forget, we don’t know everything yet! If you’re definitely not eating different, and still are gaining weight, try consulting your doctor or a good dietitian to find the cause and a solution for you. Good luck!

Have you had problems with weight management and SIBO? How did you deal with that? I’m curious about your story. Share in a comment below, or send me a message!

2 thoughts on “SIBO and Weight Gain: Does Sibo Cause Weight Gain?”

  • I disagree with what I just read. I was 115lbs before SIBO symptoms started. I was diagnosed with both Hydrogen and methane. I have severe constipation and have gained 90lbs since the onset of my symptoms. So obesity wasn’t a factor before.

    • Hi Janice, sorry to hear you’ve been having such difficulties with SIBO.
      The science says that SIBO itself wouldn’t lead to weight gain, but that doesn’t mean it is not possible. It is just not proven.
      It could also be that other factors that were present lead to the weight gain. If you want to dive into that, I’d recommend finding a specialized dietitian near you that can help.
      Regards, Manon

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