There are many things that influence your ability to lose weight, and you know what most of them are. Getting plenty of physical activity. Avoiding fattening processed foods and sugars. Eating your fruits and veggies. These changes take time and effort, but they pay off in the long run.
But there’s another factor I’ll bet you haven’t heard about. And it might just play a big role when it comes to your ability to drop weight and fight obesity.
I’m talking about your gut bacteria, what we call the “gut microbiome.”
It turns out that when your gut microbiota is out of balance, it can cause you to gain weight. In fact, people who are obese have an abundance of a group of gut bacteria known as Firmicutes. At the same time, they show a reduction in the group of bacteria known as Bacteroidetes.
The reason is surprisingly simple. Firmicutes are better able to extract energy from the food you eat than Bacteroidetes, so they promote the absorption of more calories. This, in turn, causes weight gain.
There are a lot of things that can throw the Firmicutes-to-Bacteroidetes (F/B) ratio out of whack during your lifetime. But there are a couple that stand out more than the rest.
How Antibiotics Contribute to Weight Gain
The microbial composition of your gut microbiome began before you were even born. It basically started with whatever your mom had in her uterine microbiome while you were in gestation.
Then, if you were breastfed, you got more of your mother’s microbiome. But if you took a formula, it changed in a different way. You didn’t get the usual microbes and the good HMOs…human milk oligosaccharides that come from your mother’s milk.
It changed again when you started eating the foods your parents fed you when you were six months old, like strained peas. And it changed even further when you went on solid foods.
Any antibiotics you were given at this early age wiped out your good bacteria for a good year or more. This is the kind of thing that can set you up for a lifetime of subsequent weight gain.
But that’s only the beginning.
Your gut microbiota is thrown out of balance over and over again every time you take a course of antibiotics. It can take up to four years to restore the natural diversity of your microbiome after taking certain classes of antibiotics. And some of them will shift the F/B ratio toward obesity-promoting Firmicutes for a good year or more.
And don’t forget about the antibiotics found in our food supply. About 70% of all antibiotics in the U.S. are used on healthy farm animals. These drugs are used to make farm animals grow fat more quickly. But when you eat commercial meat and dairy products, they fatten you up, too.
Still, antibiotics aren’t the only things that disturb the delicate balance of your gut microbiota.
You Are What You Eat
A Western style diet filled with bad fats and processed carbs results in a higher Firmicutes/Bacteroidetes ratio. This may partially explain why the American way of eating is linked to obesity.
However, when people who are obese start eating more of a Mediterranean style diet, they can reduce the F/B ratio by increasing Bacteroidetes and the diversity of “good” bacteria in their guts. By reducing the F/B ratio, lower amounts of energy are extracted from the foods you eat, which helps you lose weight.
All it takes is eating foods that feed your good gut bacteria… the kind that can help you get skinny.
Adding more fermentable fibers is a good first step. These aren’t the same type of fibers that you get from eating a bowl of cereal. Most cereal fibers – like wheat bran – are resistant to fermentation and are best to avoid.
On the other hand, fruits, vegetables, legumes, oats and barley are all rich in fermentable fibers. These are the ones that feed your healthy gut bacteria and increase Bacteroidetes, so you want to make sure to get plenty of them in your diet.
There are also many fermented foods you might enjoy. These foods introduce good bacteria to the digestive tract to crowd out the ones that promote obesity.
I drink kombucha every night. It’s a fermented drink that is filled with gut-friendly pre and probiotics. And I love that it’s fizzy, tangy and delicious.
You might want to experiment with miso or natto. These are fermented soy products that are loaded with plenty of bacteria that are good for your gut and help lower the F/B ratio. Kimchi – a spicy Korean dish made from fermented vegetables, and tempeh – a patty made from fermented soybeans, are also some tasty treats that can help build a rich diverseness of gut bacteria.
Other fermented foods you may be more familiar with include sauerkraut, kefir and yogurt. However, if you decide to go the yogurt route, I have a word of advice. Please stick with plain Greek yogurt that doesn’t have a bunch of sugars and other additives. Top it with fresh fruits and nuts to add flavor.
I also recommend taking a probiotic supplement every day. Look for a formula that contains a prebiotic along with lactobacillus, bifidobacteria and other strains of healthy bacteria. The higher the colony count, and the more strains involved, the better off you’ll be. Just make sure to take it daily with food.
SOURCES:
Stojanov S, Berlec A, Štrukelj B. The Influence of Probiotics on the Firmicutes/Bacteroidetes Ratio in the Treatment of Obesity and Inflammatory Bowel disease. Microorganisms. 2020 Nov 1;8(11):1715.
Magne F, Gotteland M, Gauthier L, Zazueta A, Pesoa S, Navarrete P, Balamurugan R. The Firmicutes/Bacteroidetes Ratio: A Relevant Marker of Gut Dysbiosis in Obese Patients? Nutrients. 2020 May 19;12(5):1474.
Patangia DV, Anthony Ryan C, Dempsey E, Paul Ross R, Stanton C. Impact of antibiotics on the human microbiome and consequences for host health. Microbiologyopen. 2022 Feb;11(1):e1260.
Mulder M, Radjabzadeh D, Kiefte-de Jong JC, Uitterlinden AG, Kraaij R, Stricker BH, Verbon A. Long-term effects of antimicrobial drugs on the composition of the human gut microbiota. Gut Microbes. 2020 Nov 9;12(1):1795492.
Tomova A, Bukovsky I, Rembert E, Yonas W, Alwarith J, Barnard ND, Kahleova H. The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Front Nutr. 2019 Apr 17;6:47.
Sutoyo DA, Atmaka DR, Sidabutar GBLM (2020). Dietary Factors Affecting Firmicutes and Bacteroidetes Ratio in Solving Obesity Problem: A Literature Review. Media Gizi Indonesia. 2020;15(2), 94–109. Unno T, Choi JH, Hur HG, Sadowsky MJ, Ahn YT, Huh CS, Kim GB, Cha CJ. Changes in human gut microbiota influenced by probiotic fermented milk ingestion. J Dairy Sci. 2015 Jun;98(6):3568-76.
