The current issue of Newsweek has a fascinating article on that may finally explain why your college roommate could eat a box of Krispy Kremes for breakfast every morning chased by a six-pack of coke and still look like Kate Moss while you, at the merest lick of a Krispy Kreme would gain ten pounds. In your hips. Possibly each hip.
Gut bugs may be the next frontier in weight research. (But before you click on that link I must warn you that, interesting the article may be, there is a strange picture of a headless fat man complete with man-boobs right next to no less than seven (!) ads warning you about genital warts. I’m not sure who Newseek thinks their readership is but just to be safe, don’t sleep with headless fat men. Although if you do, STDs will be the least of your worries.) The difference between you and your college roomie may be as simple as what kind of microbes colonize your intestines.
The Study
Researchers at Washington University in St. Louis conducted a series of tightly controlled tests first on mice and then later on humans. (You want the nitty gritty details?) They raised mice with no gut bacteria, obese mice with gut bacteria and lean mice with gut bacteria. They then analyzed the types of bacteria that lived in the latter two groups and did various transplanting of said bacteria into the clean mice. To test the humans they first raised babies with no gut bacteria… just kidding. All they could do was sample existing populations of obese and lean people. Although incidentally, human babies really are born with no gut bacteria – they acquire it from their mothers and their environment in the first 3-6 months of life. Exactly the same time frame as when colic resolves. A connection? I wouldn’t be at all surprised.
The Results – in mice
Clean mice (those with no gut bacteria at all) had 40% less body fat than the normal mice despite both groups eating the exact number of calories per day. Once gut bacteria were transplanted into the clean mice, they immediately gained body fat and weight – and here’s the kicker – to match the mouse from which the gut bacteria came from. So if they got “obese mouse gut bacteria” then they would become obese and if they got “normal mouse gut bacteria” they became normal. And if they got “Michael Jackson bacteria” they immediately gnawed off their own noses and spent 90% of their waking hours grooming.
Researchers identified two different kids of gut bacteria: one they called Firmicutes which were inefficient at extracting energy from food and the other called Bacteroidetes which were very efficient at extracting energy from food. The lean mice had two-thirds more Firmicutes (think firm-n-cute, what those little lean mice were) than the obese mice did. The obese mice, duh, had a two-thirds greater proportion of Bacteroidetes. The researchers, being men, likened the Firmicutes to a gas-guzzling SUV and the Bacteroidetes to an efficient Toyota Prius (although they did not extend their research to discuss, uh, gas emissions).
The Results – in humans
As was found in the mice, obese humans had a much greater percentage of Bacteroidetes and lean humans had many more Firm-n-cutes. The researchers did not try transplanting the bacteria like they did in the mice as they saw their Ethical Review Board sharpening their lawyers thereby turning the researchers into mice. But still, hope abounds that at some point this would become feasible and that humans would see the same startling results as the mice.
Caveats
One incongruent change was noted: as an obese person lost a significant amount of weight, their gut microbes went from Priuses to SUVs. This is problematic because most people who lose a lot of weight regain it and so it is surprising that the gut bacteria didn’t follow along, indicating that this whole thing is much more complex in humans than in mice. Sigh. Darn mice!
What It All Means
100 calories to you might only be 80 calories to your roommate. So when celebrities say they lost 60 pounds of baby weight in five days by eating hamburgers and exercising by running away from the paparazzi, they might actually be right. (Or have a Satanic publicist who hates women). Come one, you always knew life wasn’t fair!