SIBO-C Can Make You Gain Weight

One of the first symptoms of SIBO that sent me to my doctor two summers ago was weight gain, despite being on a restricted diet. I could tell he didn't believe me. I felt like Ingrid Bergman in the film noir classic Gaslight. (Hah, gas = methane = SIBO — hiyo!). Having SIBO-C and watching your weight can be similarly maddening.

In the film, Ingrid's husband Gregory is trying to make her seem crazy, so he can institutionalize her and claim her inheritance. One of Gregory's evil tactics is to flicker all the lights in the house which, thanks to eerie mood music, comes off a lot creepier in the movie than it sounds. Ingrid keeps telling her psychiatrist that her nerves are shattered living in that house because the lights flicker on and off all the time. But there's Gregory standing in the background, shaking his head no. And who does the psychiatrist believe? Yeah, it's like that.

Because my weight gain was occurring along with symptoms like muscle cramps, joint pain, hair loss, dry skin, and feeling cold all the time, I suspected hypothyroid. My doctor at the time ran the standard blood and urine screens and my TSH level was within what's considered normal range. I had read at Stop the Thyroid Madness that the TSH test is not a good indicator, and I asked him if he could test my free T3, free T4 and reverse T3 levels and also look for thyroid antibodies. He handed me a lab sheet and said check off the tests you want and mail it back, but I'm telling you right now, I'm not prescribing thyroid medication to a patient whose TSH is in range.

Whoa! — who said anything about thyroid meds? I'd just asked to learn what my hormone levels are.

As a parting shot as he was walking me out, he said try a low-carb diet. But I was already on a low-carb diet. I'd eating low carb for most of the eight years I'd been his patient.  In fact, as I would soon come to find out, a low-carb diet for so many years may have been a causal factor in my gut dysbiosis.

Recovering from a shoulder injury that grounded me from my usual summer activities like biking and kayaking, I was concerned about weight gain, so I had been eating even fewer carbs than usual. I'd been watching my diet extra carefully and keeping an online food diary. What I was seeing was very strange. For most of my life when I was active I could eat 1800 calories a day and maintain my weight. When I needed to lose weight, reducing consumption to 1600 calories a day would result in about a two pound weight loss per week. But now here I was down to 1200 calories a day and steadily gaining weight.

I could tell he didn't believe me, so I exported my food diary into a PDF and sent it to him, but was met with stony silence. He wasn't the only one not listening. Even some of my closest friends were saying unhelpful things, like "a calorie is a calorie" and "there were no fat people in Auschwitz." And I couldn't blame them, as I'd spent a lifetime subscribing to the same "eat less, move more" philosophy.

If you have SIBO-C and think you're gaining weight even on a restricted diet, it's not all in your head. This paper by SIBO pioneer Dr. Mark Pimentel explains how methane gas production in SIBO-C leads to constipation, irritable bowel syndrome (IBS), and obesity.

In this Chris Kresser podcast, Dr. Pimentel further explains:

"... Methanogens, it turns out, based on the microbiome work that’s being done on that particular organism, are super important to help liberate calories from nondigestibles. So let’s say you have a high-fiber diet. Humans generally can’t eat fiber. Cows and ruminating animals have a lot of methanogens because the methanogens help facilitate digestion of fiber. So what does that mean? That means that you can get more calories from a meal if you’re a methane producer because you’re liberating calories from things that people who don’t have methane can’t get.

So where am I going with this? What I’m saying is if you take a population from Africa and immigrate them into the United States, and those folks, for genetic reasons or environmental reasons, have methanogens flourishing in their gut, which is an evolutionary advantage for getting and harvesting nutrients, it’s not an advantage when food is abundant and food is so processed and easily digested that you get more calories."

Hearing this from the world expert on SIBO didn't help cure my condition, but it did explain what was happening in my body. The bacteria colonizing my small intestine are extracting MORE calories from fiber foods that I eat.

I'm all for efficiency, but just once in my life I'd like to have the ailment that makes a person LOSE weight!