How Your Gut Microbiota Tip the Scales on Weight Loss
These tiny inhabitants play an overlooked role in obesity
During our evolutionary history as a species, food shortages were common, and the ability to store energy as fat was advantageous for survival. In the modern world however, where food is easily accessible, the same behaviors that once helped us may now hamper our progress.
When we discuss metabolism, we usually only focus on our own contributions to physiological processes in our bodies. But the contribution of our microbial inhabitants is equally, if not more, important.
A sizeable body of evidence has shown that the human gut microbiota determine the effects of both diet and exercise on weight loss and metabolism.
Got Guts?
Our intestines are home to trillions of microorganisms. While most microbiome research so far has focused on bacteria, we also harbor many different types of archaea, protists, fungi, and viruses.
These microbes contribute to digestion and immunity, protect against pathogens, provide nutrients, influence our risk for chronic diseases, drive social behavior, and impact our metabolism.
Certain bacterial signatures predict body-mass index (BMI), while baseline microbiota profiles help explain why some dieters shed pounds easily and others plateau.
The Energizer Bunny in Your Gut
In 2006, Dr. Jeff Gordon’s lab began to elucidate the connection between diet, the gut microbiota, and obesity. His early research discovered that the microbiomes of obese mice are enriched in genes that allow more energy to be harvested from the diet. Studies estimate that around 10% of the calories in a typical Western diet come from these microbial conversions.
Transplanting the gut microbiota of obese mice into lean mice resulted in obesity even without an increase in food consumption. Studies have also shown that transplanting gut microbiota from obese humans into germ-free mice leads to greater weight gain and fat accumulation than transplants from lean individuals.
