Rainforests are Earth’s oldest living ecosystem. They cover only 6% of the Earth’s surface, yet they contain more than one half of the world’s plant and animal species. You may never get the opportunity to see a rainforest, but you are actually living very close to another type of ecosystem. It’s called a microbiome, and it resides primarily inside your gastrointestinal tract. It contains trillions of bacterial cells that help you digest food, as well as influencing your appetite, metabolism, immune system and mood. Your microbiome also affects your risk for disease, one of them being obesity. Your intestines literally house a “microbial ecosystem” that works hand-in-hand with your human cells. It is imperative that those two ecologies work in harmony and maintain a symbiotic relationship to support each other’s (and by extension your) health.
How can they do that?
The more diverse your microbiome, the easier it is to manage your weight. As humans, we share 99.9% of the same human DNA. But no two people share the same microbiome. We acquire different bacterial strains through our family, co-workers, pets, and perfect strangers. We also change it daily with our food choices. It is an ever-evolving process, and one that you actually have a lot of control over.
Research into the causes of obesity has shown that (1) composition of gut microbiome plays a significant role in weight gain. Obesity is also associated with (2) a decrease in the overall diversity of your gut bugs (even though the total number of “bugs” may remain the same). What essentially happens is that certain groups of (not-so-great) bacteria take the place of other (healthier) bacterial groups. The replacing bacteria are better at harvesting energy from food than the bacteria they replaced, thus resulting in increased calorie intake and an increase in weight.
Picture this: someone in your neighborhood builds a new home. To do that, the yard is ripped up while the home is being built. At some point, landscaping and new grass will be planted, but until that happens, you will probably see many weeds growing in the dirt. That’s because the bad growth has lots of opportunity to survive with the good stuff gone. The same thing is true in your body. If you go on an antibiotic and kill off a lot of your good bacteria, it will give bad bacteria an opportunity to flourish. As well, if you make food choices that don’t support the colonies of good bacteria you need, others will take their place. That imbalance in your microbiome may ultimately make it easier to gain weight, and conversely, harder to lose it. Yikes!
What should I eat to maintain a healthy microbiome (and weight)?
The best food choices for a healthy microbiome are plant foods. Most whole plant foods contain decent amounts of fiber. Examples would be the seeds, strings, peels, skins, pulp, and bran present in fruits, vegetables, and whole grains. Those fibrous bits and pieces remain intact all the way to your colon, where they become food for the good bacteria that live there. Your gut bugs ferment them, break them down, and provide us with awesome byproducts such as butyric acid, acetic acid, and vitamins. Constantly eating fast food or foods high in fat and sugar may cause bad bacteria to bloom and good ones to disappear.
If pressed, most of us would admit that we need to eat more fruits and vegetables. They provide vitamins, minerals, fiber, and antioxidants. They are also low in calories, so including them in your meals or as snacks will enhance your efforts to lose weight. But plant foods are the primary fuel for our gut bugs, and improved bacterial colonies enhance our efforts to lose weight as well. Gut bugs and microbiome. Who knew??
Written by: Donna Green, Extension Educator, Ohio State University Extension, Family and Consumer Sciences, Erie County, Erie Basin EERA.
Reviewed by: Liz Smith, Extension Educator, Family and Consumer Sciences, Ohio State University Extension.