Diet: Why Some Fats May Be Bad

Some fats (like animal fats) are linked to ailments like heart disease and diabetes while others (like those from fish, plants, and nuts) have health benefits. Why the difference? The results of one study suggest that some fats encourage the growth of harmful bacteria in the digestive system. Our bodies recognize those fats and launch an immune response. The result is low-level inflammation that, over the long term, causes chronic disease.
Quarterly Review of Biology, September 2012