Bugs and diet

As has probably been suspected for a long time, it seems gut bacteria can make a big difference to successful weight loss.  The way it works is pretty interesting, though.  NPR writes:

"We found that people who lost at least 5 percent of their body weight had a different gut bacteria as compared to those who did not lose 5 percent of their body weight," Kashyap explains. Their findings are published in the journal Mayo Clinic Proceedings.

The successful dieters had an increased abundance of a bacteria called Phascolarctobacterium, whereas another bacteria, Dialister, was associated with a failure to lose the weight. And, Kashyap says it's likely that there are other types of bacteria that might influence dieting as well.

So, how might bacteria influence weight loss? It turns out we can get a significant number of calories from our microbes.

Here's how it works: Consider what happens when you eat an apple. You digest most of it.
"But there's a certain part of the apple we can't absorb," explains Martin Blaser, a professor in the Department of Microbiology at NYU Langone Medical Center. "We don't have the right enzymes to digest every bit of [the apple], but our bacteria can."

Think of it this way: The bacteria eat what we can't.

And, in the process, they produce byproducts that we can digest. So these byproducts become another source of calories for us.

The new study suggests that certain bacteria — or mix of bacteria — may be more efficient at creating "extra" calories for us to digest.

"Somewhere between 5 to 15 percent of all our calories come from that kind of digestion, where the microbes are providing energy for us, that we couldn't [otherwise] get," Blaser explains.

This calorie boost could be beneficial if food were scarce. "If times were bad, if we were starving, we'd really welcome it," Blaser says.

But at a time when many people want to lose weight, these extra calories may be an unwanted gift.