uBiome’s 7 Secrets About How Some Gut Bacteria (like Firmicutes) Can Make You Fat

They’re unseen, largely unknown, and number in the trillions, but your gut bacteria can make you fat. We’re talking Firmicutes and Bacteroidetes. Here’s the story and what you can do about it.

fat making gut bacteria

THE FINE folks over at uBiome kindly gave me permission to offer you their most recent guide, 7 Secrets About Bacteria and Weight Loss.

UPDATE: Whether they were fine or not, uBiome is out of business. Do read the rest of this article to learn more about the importance of your microbiome and how to take care of it, but references to uBiome may be disregarded.

The rest of this is my summary of their “7 Secrets”, along with my typical liberal dose of opinion and added resources for the intellectually adventurous.

Just like it’s presented in their Table of Contents, I’m going touch on the following:

  1. Overweight people have less bacterial variety
  2. Eat beans to get bacteria like a skinny person
  3. Meat that contains antibiotics can lead to weight gain
  4. Cut your risk of Type 2 diabetes by boosting bacterial diversity
  5. Fool your brain into believing you’re not hungry
  6. Taking fiber supplements can work as well as fiber from food
  7. Stop your bacteria from eating into your gut lining

You can skip my commentary and additional resources I present and get right to the source of much of the following info by clicking here and downloading uBiome’s “7 Secrets” pdf file. Those of you who would like some extra sauce can keep reading.

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Before we begin, I want to emphasize why this topic matters.

The people of the industrialized world are getting fatter and unhealthier despite the trillions of dollars spent on healthcare. The reasons are simple if not easily overcome:

  • We sit a lot and move little
  • We mostly eat manufactured food that looks, and is, nothing like real food – the stuff the farmer’s make
  • We get insufficient deep sleep
  • We’re stressed

Worldwide Obesity(Read more about this at Worldwide Obesity: A Frightening Look at The Facts)


All this has impact. The impact is poor health and a soft body.

According to a study described by CBS News, “nearly 70 percent of Americans are on at least one prescription drug, and more than half receive at least two prescriptions.” (1)

If you eliminate everyone less than 40 years of age, what do you think the percentage climbs up to?

This isn’t normal.

Now to the soft bodies…

Have you ever noticed old film, say taken during the first half of the 20th century, where the footage is of large groups of people? Maybe they’re in a stadium, or at a railway station, or a convention.

Do you notice how almost everyone is of normal weight?

Now contrast that to the same scenes happening today. Well, if you see that six of every ten person you observe is either overweight or obese, you’re perception is spot on.

According to the U.S. Department of Health and Human Services, more than two-thirds (68.8 percent) of American adults are considered to be overweight or obese. (2)

Europeans don’t fare much better — The United Nations health agency estimates that 58.6% of this population is overweight, and 23% are obese. (3)

Want a broader context? The Institute for Health Metrics and Evaluation presents new data that show about one-third of the world’s population is obese or overweight, and that no country has reduced obesity rates in 33 years. (4)

Could this fat epidemic be caused by too much of the wrong bacterial in our guts?

No, that would be a stretch, and I already mentioned some basic reasons our girths are approaching beach ball dimensions. But, as you’re about to discover, our microbiota – the bacteria in us that outnumbers our own cells – is a significant part of the mix, and can be an important part of how we deflate a bit.


#1. Variety Is The Spice Of Life

There’s an estimated 100 trillion bacterial critters in and on us, much of them forming a very active microbiome in our gastrointestinal tract. Just like with the animal and plant kingdoms, these bacteria are not all the same, and they do not have the same effects on us, their hosts.

human microbiome

I’ve written about some very significant influences that our microbiota have on us. The article, 100 Trillion Reasons You’re Fat, Sick and Depressed, Part 1, showcases recent scientific studies that indicate how the bacteria that constitute our microbiota establish a microbiome (a fertile, animated bacterial environment within us) that influences body composition, immunity and even brain function.

Pertinent to the subject at hand — how certain kinds of bacteria in us contribute to our fatness, or leanness — Claire M. Fraser, Ph.D., professor of medicine and microbiology and immunology and director of the Institute for Genome Sciences (IGS) at the University of Maryland School of Medicine, said this:

“We identified 26 species of bacteria that were correlated with obesity and metabolic syndrome traits such as body mass index (BMI), triglycerides, cholesterol, glucose levels and C-reactive protein, a marker for inflammation. We can’t infer cause and effect, but it’s an important step forward that we’re starting to identify bacteria that are correlated with clinical parameters, which suggests that the gut microbiota could one day be targeted with medication, diet or lifestyle changes.”

Now, although the good doctor said that we “can’t infer cause and effect”, times are-a-changing, and now we have some compelling evidence.

As uBiome reports in their “7 Secrets”, when bacteria from obese humans were transplanted into mice, the mice gained weight. (I guess there were no lean humans who volunteered.) They ate the same food as another group of mice, the control group, that were exactly like the “humanized” mice except for the bacteria transfer. Clearly, then, t’was the obese human gut bacteria inserted into the mice that made them gain weight.

Although scientist have yet to discover some “fat bacterium”, they do observe that fat and lean people have differing amounts of two types, or phyla, of bacteria, which I’ll address below. Moreover, fat people have less bacterial diversity.

This is unsurprising to me.

The people I know who are overweight tend to eat fewer food types, or to put it in another way, less food diversity.

The tongue can detect five flavors that neurons in the brain interpret as:

  1. Salty,
  2. Sweet,
  3. Savory
  4. Sour, and
  5. Bitter (5)

I’m going to assert without any research or scientific support at all that, on average, overweight people predominately apply their palate to the first three – Salty, Sweet and Savory – and thereby cultivate less bacterial diversity in their gut.

Or, as Pulitzer Prize-winning New York Times investigative reporter Michael Moss might say after spending four years researching the fast food industry, people get and stay overweight because of their compulsive eating of the “Holy Trinity of sugar, salt and fat. (6)

What to do? Begin by “eating the rainbow”, which pretty much means more fruits and veggies of various vibrant colors, AND eat prebiotic and probiotic foods, such as sauerkraut, pickles, kefir, yogurt (without the fruit) and kimchi. The common denominator is that they’re all fermented food.


#2. Beans Aren’t Just Good For Flatulence

In that quote of Dr. Fraser above, she mentioned “26 species of bacteria that were correlated with obesity and metabolic syndrome…” etc. Rather than try to remember those 26 species of bacteria that you want to avoid (which she didn’t name anyway), take note of two bacterial phyla, Firmicutes and Bacteroidetes.

One you want; the other not so much.

It’s been discovered that obese people have more Firmicutes and less Bacteroidetes than lean people. Strangely, when this happens, there’s an imbalance between these two types of bacteria, which results in the gut becoming more efficient at extracting energy from food.

Efficiency is usually good, but in this case, not.

Back to the mice.

When the microbes of mice are changed such that they have more Firmicutes than Bacteroidetes, the mice absorb more calories than before the change, even though they eat the same amount of food. The predictable result is that they gain weight.

And, if your Firmicutes-to-Bacteroidetes ratio is imbalanced, so might you.

What to do? Increase your Bacteroidetes count by eating the foods they love, which are foods containing lots of dietary fiber, such as beans, legumes and veggies.


#3 Eat Pure Meat Only

“Pure meat” means meat grown without antibiotics and growth hormones. Antibiotics are no longer used in animal feed only to help keep them healthy. The livestock industry discovered that animals on antibiotics fattened up, and now they’re used abundantly, indiscriminately, which begs the question poised by uBiome:

“If antibiotics can fatten a cow or chicken, why wouldn’t they have a similar effect on a human?”

Well, grasshopper, they would and do!

Just ask the Navy.

Several hundred Navy recruits were fed antibiotics every day for seven weeks, and they gained more weight than the control group. This can happen merely by eating the meat from an animal fed antibiotics. (7)

What to do? Eat humanely raised, pasture-fed, antibiotic and hormone-free animals. Realtimefarms.com/fixantibiotics lists retailers, farmers’ markets, and eateries that sell meat without antibiotics.


#4 Get Sensitive To Diversity

Back to diversity. It’s good in human populations and it turns out that it’s good in bacterial populations as well.

People with less diversity of bacteria in their microbiomes are more likely to suffer from inflammation, and are more resistant to insulin than their more diverse counterparts.

As you probably know, insulin resistance can lead to high blood sugar, and if you get enough of that long enough, here comes Type 2 diabetes, which along with its partner-in-arms, obesity, creates a medical condition that Dr. Mark Hyman calls “Diabesity”, which is so wide-spread that he thinks threatens the solvency of health care in America.

What to do? (1) Allow yourself exposure to a wide assortment of bacteria, much of which is eliminated by over-sanitization, so use soap and water rather than anti-bacterial hand-sanitizers. (2) Eat fermented foods. (3) Eat prebiotic foods, such as asparagus, artichokes, onions, garlic, oats, and beans. Read How To Feed 100 Trillion Guests.


#5 Those Tiny Brain Whisperers

We’re talking Bifidobacteria, one of the major genera of bacteria that make up the colon flora in mammals, some of which are used as probiotics. (8)

Turns out that rodents fed something called oligofructose get higher levels of Bifidobacteria in their guts than the control group, which led to less food consumed, less fat mass and less fat build-up in their livers.

Yes, it seems that the brain talks to the gut and the gut talks back.

And, if you’re a human reading this, you’ll be pleased to know that was people, not rats, who in a Belgium study consumed eight grams of oligofructose each day with breakfast and dinner, and wound up feeling fuller and eating less. Happily, this usually leads to losing weight, although there was no reference to such in the uBiome synopsis of the study. (9)

What to do? Eat a bunch of oligofructose of course, which you’ll find in vegetables such as onions, bananas, garlic, chicory, and various supplements, my favorite being Swanson’s Inulin powder, which inevitably finds its way into my morning smoothie.


#6 Supplemental Fiber’s On The Menu

Speaking of supplements, getting that extra fiber to grow your Bacteroidetes population can effectively be done via supplementation.

If you just can’t bring yourself to eat the rainbow, or whatever else is good for you, then go get some fiber supplements and take them daily.

Even those over-hyped food bars can do the job, if they contain a high dose of fiber. This was proven in an experiment conducted at the University of Illinois with 20 healthy men, writes uBiome. The control group ate a snack bar without fiber for 21 days, and another group at a fiber-enriched snack bar that contained 21 grams of polydextrose, a fiber additive, over the same time period.

You know the drill by now – all that ingested fiber resulted in a shift in the ratio of Bacteroidetes (more) and Firmicutes (less), which, as I’ve been beating the drum about, can lead to weight loss.

What to do? You can do better than polydextrose… Dr. Hyman recommends PGX with Mulberry Extract, which comes in capsule form. If you rather munch on a snack bar, try Dr. Mercola’s Cocoa Cassava – you’ll get fiber, protein and some healthy omega-three fatty acids.


#7 Keep Your Gut Lining Off The Menu

You do know that eating fiber helps make you regular, sorta speak, in the poop department, right?

What you might not know is that fiber also keeps bacteria prone to misbehaving from eating your gut lining.

This is worthy of quoting from “7 Secrets”:

Researchers at the University of Michigan Medical School discovered that the microbes of mice who were fed a fiber-free diet began to eat away at the gut’s protective mucus lining, potentially triggering inflammation. Systemic inflammation has important implications for many aspects of health, leading to cardiovascular illness, dementia, gastrointestinal disorders, Type 2 diabetes, and plenty of other conditions. It may also be the cause of weight gain.

When inflammation interferes with the gut barrier (which among other things keeps pathogens out of the bloodstream), bacteria-derived toxins are able to get in to the bloodstream. A breached gut barrier can also lead to adiposity, where fat gets stored in your fatty tissues, and weight gain.

Most adults in the West eat far too little fiber. The Institute of Medicine recommends that women should get 25 grams per day and men should consume 38 grams, but the average daily intake is just 15 grams. Eating fiber as part of a weight-management program makes a lot of sense. (10)

I’d like to add that the more it’s studied, the more that chronic, systemic inflammation is being considered by scientists to be a precursor for many chronic diseases, and even aging itself. Inflammation is something we really want to keep in check.

What to do? Men, consume 38 grams of fiber each day. Women, your mark is 25 grams. Food sources include beans, legumes, peas and veggies. Particularly potent is pea protein. Read my blog post, The 4 Food Solution to the 100 Trillion Reasons You’re Fat, Sick and Depressed (Part 2).

OK, I’m done, but you’re not until you go check out uBiome’s 7 Secrets About Bacteria and Weight Loss from which much of this blog post information was sourced.


Last Updated on April 11, 2023 by Joe Garma

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Joe Garma

I help people live with more vitality and strength. I'm a big believer in sustainability, and am a bit nutty about optimizing my diet, supplements, hormones and exercise. To get exclusive Updates, tips and be on your way to a stronger, more youthful body, join my weekly Newsletter. You can also find me on LinkedIn, Twitter and Instagram.

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