While 40% of Americans are obese, some of them actually eat less—and exercise more—than their thinner peers. So what’s at work here? Could obese people really have a “fat gene” that prevents them from losing weight? In fact, recent research indicates that it’s the lack of particular gene activity that might cause the trouble…

Previous recent studies have linked inflammation to obesity and diabetes. But scientists have now found that a specific anti-inflammatory gene—called NLRP12—protects mice against obesity and insulin resistance when they eat a high-fat diet. It appears that NLRP12 promotes the growth of a beneficial gut bacteria that wards off inflammation and weight gain. So an NLRP12 gene that isn’t firing on all cylinders may contribute to obesity.

Breakthrough implication: This finding may ultimately lead doctors to an effective new way to fight weight gain…and thereby lower the risk for obesity-related diseases such as cancer, heart disease, stroke and diabetes.

Study details: Investigators at University of North Carolina genetically altered mice to eliminate the NLRP12 gene. They then fed these mice and a group of ordinary mice a high-fat diet for several months. The mice without the gene did not eat or drink any more than their peers, but they gained significantly more fat, became heavier and had signs of inflammation in the gut.

When researchers later fed the beneficial bacteria Lachnospiraceae to the mice who lacked NLRP12, the harmful inflammation was reversed and the mice were protected from further weight gain. Researchers explained that Lachnospiraceae contain enzymes that convert carbohydrates and fiber into short-chain fatty acids, such as butyrate and propionate, that have anti-inflammatory properties.

Can this work for humans? A follow-up investigation indicates that it might. Scientists in the Netherlands studied fat cells from obese humans and found that the higher a subject’s body mass index, the lower his/her NLRP12 gene activity (as explained earlier, NLRP12 promotes good bacteria that curb inflammation). This finding supports recent research that human obesity is also influenced by inflammation, not just by eating and exercise habits.

What’s next? Further studies are needed to determine if supplementing with beneficial bacteria or short-chain fatty acids could be a relatively inexpensive way to promote weight loss and lower the risks for diabetes and other obesity-related diseases.