A Nature Metabolism study found that mice on ketogenic diets excreted feces with higher caloric content, measured by bomb calorimeter. Elevated conjugated bile acids increased energy loss through stool, suggesting keto's metabolic advantage partly comes from absorbing fewer calories. The microbiome's role in bile acid production may explain why low-carb diets raise maintenance calorie needs.
Yes, pooping calories. Indeed, when the researchers took feces from mice treated with towering conjugated bile acids and threw it into a bomb calorimeter and blew it up, there was indeed more calories in the feces from mice treated with towering conjugated bile acids than controls. Don't make an explosive diarrhea joke right now. Don't do it, don't do it. Okay, good. That was a clip from a long-form video I just posted on a metabolic advantage of ketogenic diets. Now, it's been known for a long time that ketogenic diets have a metabolic advantage whereby maintenance calories go up when you're lower carb. Part of this has to do with increased energy expenditure, but also part might have to do with decreased energy absorption. And this new paper published in Nature Metabolism, they discover how changes in the microbiome might increase levels of certain bile acids that lead to pooping of more calories. How interesting is that?
