Your gut microbes can have a considerable impact on the size of your waistline.

The human gut is colonized by tons and tons of bacteria. A thought that’s not only strange, but also perhaps a little gross. Yet here’s another strange fact: these colonies play a huge role in your health.

Let’s start with how much you weigh. Interestingly, the type of bacteria you’ve got in your gut can determine whether you stay slim or become obese.

Two groups of bacteria are accountable for some 90 percent of your gut’s microbiome – firmicutes and bacteroidetes.

While scientists don’t know the “ideal” ratio of these groups, they do know that when you have more firmicutes than bacteroidetes, you can suffer from increased inflammation and potentially from obesity.

Firmicutes are expert at extracting energy from the food you eat, which means that they help you consume more calories. In contrast, bacteroidetes aren’t so much involved with calorie extraction but work to break down plant fibers and starches.

Harvard researchers examined the connection of obesity and a person’s microbiome, focusing on two groups: people living in Western countries and in Africa. Considering that obesity is virtually non-existent in Africa, any differences in microbiome were viewed as notable.  

And what researchers found was indeed notable. Africans had more bacteroidetes in their gut, while Westerners had more calorie-extracting firmicutes. So having more firmicutes may be at least partly responsible for the obesity epidemic in the West.

Your microbes not only help to keep you slim (or fat) but also help support your liver. Many foods contain environmental toxins; it’s the liver’s job to get rid of these once in your body.

Yet a healthy gut can also support the liver in its work, which is why the gut is often called the body’s “second liver.”

Gut microbes help to neutralize toxins that reach the intestines, acting as a first line of defense. In doing so, the microbes take a bit of pressure off the liver, keeping it healthier!