It began with two mice—one skinny, one fat. Scientists moved the gut bacteria of the fat mouse into the skinny mouse.
Here’s where things get interesting: within two weeks, the skinny mouse was fat. Not because it was eating more. Not because it had switched its diet around.
The skinny mouse was fat because it harbored the same gut bacteria as the fat mouse.
The results of this experiment were published back in 2006, when researchers had just begun piecing together the difference between “obese” bacteria and “lean” bacteria.
Since then, we have learned that gut bacteria interact with many systems in the body—influencing inflammation, appetite, how much energy you harvest from food, and how much energy you store as fat.
In other words, your gut bacteria talk to your brain, your immune system, and even your fat cells.
Obesity is marked by inflammation—when you're overweight, you're inflamed. What's more, your gut bacteria can make or break low-grade inflammation.
What Gut Bacteria Can Teach Us About Weight Loss
All in all, the microbes living in your body encode 150 times more genes than your own genome. So, chances are high that the bugs living in your gut can do a lot that you can’t. Like break down dietary fiber, digest gluten and turn hard, tough plant roughage into a special anti-inflammatory fat that nourishes intestinal cells.
But what happens when your microbial landscape changes? Your body changes right along with it!
Imbalances in your inner ecosystem help explain why some people struggle with weight loss while others do not.
Stubborn fat is not just a story about calories in and calories out—your environment matters. Your genes matter. Your gut bacteria (and their genes) matter.
Fat Firmicutes and the Gut Factor
Over the last decade, we've learned that 90 percent of the bacteria living in your digestive tract are from two groups: Bacteroidetes and Firmicutes.
People with an imbalance of Firmicutes often carry more weight, fight hard to lose fat, and are more inflamed. Brenda Watson, author of The Skinny Gut Diet, fittingly calls Firmicutes your “Fat” bacteria and Bacteroidetes your “Be Skinny” bacteria.
If there’s any one group of bacteria that’s linked to stubborn fat, it’s the Firmicutes.
Before you swear off Fat Firmicutes forever, know that the most famous family of probiotics—Lactobacillus—belongs to the Firmicutes group.
Like all things in life, there is no stark line between good and bad. Indeed, researchers have found that balance and diversity are more important than any one group or species of bacteria.
Brenda Watson calls this the gut factor.
When it comes to weight loss, many people overlook the gut factor and instead target calories or macronutrients, like fat, carbohydrates and protein. But a healthy, balanced inner ecosystem is pivotal to your weight loss goals.
How to Win Your Battle Against Fat
Researchers recently found that big dietary changes in a small amount of time can dramatically shift your inner ecosystem.
For example, a diet filled with animal products (like meats, cheese, and eggs) and saturated fat will favor bacteria that thrive around bile, a substance the body uses to digest fat. Unfortunately, some of these same bacteria may also contribute to the development of inflammatory bowel disease.
In a nutshell: The microbes living in your gut are extremely sensitive to diet. This is an adaptation that took place thousands of years ago, when feast or famine was the norm.
The foods that you eat select which bacteria will live in your gut and which will not.
This means that your weight loss goals are within reach! Once you learn how to feed the right bacteria with a plant-based diet and cultured foods, you can begin to intentionally shape your inner ecosystem and lose weight.