Could the 'Ulcer Bug' Guard Against Obesity?

International review of countries found higher H. pylori rates corresponded with lower obesity rates

But whether H. pylori makes a real difference in the battle of the bulge is hard to pin down, according to Holtmann.

For example, the gut is home to trillions of bacteria that are thought to affect digestion, immune function and possibly weight control. And people with and without H. pylori may have a generally different gut-bacteria makeup, Holtmann's team pointed out.

"The data suggests that either H. pylori itself or other infectious factors linked with H. pylori are significant," Holtmann said.

Ochner called the new findings "very interesting," and he agreed that it's plausible the ulcer bug could have some positive effect on weight.

But he doubted that it could make a big difference on anyone's bathroom scale.

"Body weight is incredibly complex," Ochner said. "It involves so many factors. And in my opinion, this will not turn out to be one of the big ones."