Good Gut Bacteria Burns More Calories, While You Sleep

It’s not just a late-night television ad: you really can burn calories while you sleep. Actually, you already do burn calories while you sleep, but you can burn more of them if the bacteria in your gut is healthy. That finding comes from researchers at the University of Iowa, were a study has shown that drug-induced changes to the gut microbiome can cause obesity, mainly by reducing the resting metabolic rate—the rate at which calories are burned while sleeping or resting. In other words, microbes in our guts are responsible for calories burned while we sleep. An earlier study by the same researchers indicated that weight gain was correlated with a significant shift in the composition of gut microbiomes. When the researchers measured calorie burn (they calculated energy intake, oxygen consumption and carbon dioxide output, and heat production), they learned that there was no change in aerobic (oxygen-dependent) resting metabolic rate for mice fed risperidone (an antipsychotic drug that causes significant weight gain in patients and shifts in the microbe) compared to control mice, but there was a significant decrease in non-aerobic resting metabolic rate sufficient to account for the animals’ weight gain. How significant? “It’s about a 16 percent change in resting metabolic rate, which is enormous,” says Justin Grobe, assistant professor of pharmacology. “It would be 29 pounds of fat gained every year for an average human.” Or, as another investigator puts it: It’s the equivalent of eating one additional cheeseburger every single day.