His team isolated enterobacter microbes from their human subject’s stool samples and mixed them with food given to special “germ free” mice. These blank-slate animals are born in sterile environments where bacteria can’t colonize the digestive system, giving scientists control over what they’re studying.
The bacteria turned the mice into textbook obesity cases, complete with weight gain and signs of diabetes, but only when the animals ate a high-fat diet. Animals on a leaner diet didn’t gain weight — likely because there was no excess energy for the bacteria to convert to fat with its toxins.
Supplemental material distributed to reporters in China included graphs (p. 48) showing a dramatic difference in weight between the bacteria-altered mice and “control” animals given the same diets.
Policy disagreements about the reasons for increasing obesity rates have raged for decades, with public health researchers blaming food producers and restaurant companies for what some call an “obesogenic environment.”
The food industry has blamed a lack of physical activity for the nation’s weight gain, including sedentary behaviors brought on by modern conveniences like automatic dishwashers, television remote controls and public transit systems.
Pharmaceutical companies and those that produce bariatric-surgery equipment, meanwhile, have subsidized public health research examining the depth of the problem and recommending health care and government-entitlement coverage for their branded products.
About 120 million Chinese men, women and children are considered obese, according to the country’s health ministry. In the United States, the latest obesity statistics from the Centers for Disease Control and Prevention suggest that more than 78 million adults are obese, along with about 12.5 million children and adolescents.