Could overweight be genetic?

In what turns out to be a rather confusing study, Nature magazine reports that people who are obese have many more microbe types in their intestines that are very efficient at extracting energy from food than thin people do. They also found that another microbe type that's less efficient increases as a person diets and is higher in thin people.

Lest you get too excited, as I started to, thinking okay, yeah, this means my fat is genetically determined, they're not willing to go that far yet. But they see some suspicious stuff when they take these gut flora from obese mice and implant them into normal mice--those normal guys put on a lot more fat than could be expected just from that one change. They're going to keep studying, because it's not clear yet which comes first--does the change in flora bring on the weight loss or vice versa? But there's hope that one day we might be able to take a couple of spoonfuls of something that will use our natural body composition to make us less susceptible to gaining weight and/or more likely to be able to lose it when we try.

Now wouldn't that be a joy? But it could wreak havoc with one segment of the publication industry. What in the world will the women's magazines fill their covers with? Oh, yeah, I forgot: "How to turn him on...and keep him on."

If you want more scientific details on intestinal stuff: Gut Bacteria May Determine Dieting Efficiency.