A recent study published in the scientific journal Science investigated the relationship between gut bacteria, diet, and weight gain. Gut microbes were transplanted from a pair of human twins, one obese and the other lean, into germ-free mice. As seen in previous studies, the sterile mice who received microbes from the lean twin (“lean microbiota”) stayed lean, while mice who received microbes from the obese twin (“obese microbiota”) gained weight.
The interesting findings came when the researchers put the mice in the same container, and the obese and lean mice began sharing microbes between each other (eating each other’s droppings). When the lean and obese mice both got a diet low in saturated fat and high in fruits and vegetables (prebiotics), the microbiota of the lean mice colonizes the obese mice and prevented them from gaining weight. When the researchers repeated the experiment, but gave the mice an “unhealthy” diet high in saturated fat and refined foods, the microorganisms from lean mice weren’t able to prevent the weight gain in the obese mice. These findings support previous research showing that you can lose or gain weight by changing your microbiome.