The Role of Bacteria in Weight

I admit, I’m fascinated by the science of eating and weight and thrilled at how far we’ve come from the simplistic notion that slimness is merely a matter of self-control and willpower. The newest headline to catch my eye is “Bacteria in Intestines Play Key Role in Weight Gain, Study Finds”( LA Times, 11/12/09). Its conclusions are enlightening.

Reporting on the results of a study on mice in Science Translational Medicine, Thomas H. Maugh II says, “A high-fat, high-sugar diet…alters the composition of bacteria in your intestines, making it easier to gain weight and harder to lose it.” According to researcher Jeffrey I. Gordon, MD, of Washington University in St. Louis, 90% of the bacteria in our gut (needed to digest food) falls into two categories: lean rats have more Bacteroidetes and heavy mice have more Firmicutes. Because Firmicutes are more efficient at converting food into calories, mice with more of them are—you guessed it—likely to gain weight easily. Even when researchers swapped Firmicutes and Bacteroidetes back and forth between lean and heavy mice, they got the same results, that is, the Firmicutes drove weight gain when mice were fed high diets of fat and sugar. 

Now we know that not every study that involves mice is applicable to humans, but it makes sense in terms of these bacteria. So, what does this knowledge mean for you? That you need to swear off all high-fat, high-sugar foods? That if you have more Firmicutes than Bacteroidetes (and, without testing, who knows which among us have what bacteria in our guts?), you should give up on trying to eat “normally”? Or does it make you feel relieved that you’re not crazy because it seems as if even the tiniest bit of high-sugar or -fat foods packs the pounds on you?

I blog often about scientific discoveries related to food and weight not to specifically change attitudes about eating one way or another, but to keep you informed. What is interesting to me is that most of us may fall prey to using new information to back up assumptions we already hold—we glom onto data that reinforces what we believe and screen out what doesn’t gel with previous thinking. I’m hopeful that when you’re presented with new information such as this news about gut bacteria that you will stop and think how it might work to improve your relationship with food rather than use it to reinforce established belief or practice. With any new information, it’s useful to wonder how it can impact or change your thinking and behavior. Curiosity and an open mind are what's needed to alter your eating habits, and the more you know about the subject, the better your chance of resolving your problems.

Best,

Karen

http://www.eatingnormal.com/

http://www.nicegirlsfinishfat.com/

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Comments

[sue corning]

Intestinal bacteria can also influence people to have gut pain and diarrhea or constipation, eat less and LOSE weight. We have billions of bacteria in our intestines, some good (which help digestion), some not so good (but not bad in low amounts), and some very dangerous. Having enough good bacteria (especially by taking probiotics) helps us keep those not so good bacteria under control. However an excess of the not so good bacteria or any really bad bacteria (like E. coli, Salmonella, Clostridium Difficilie or c-diff, etc.) can cause painful intestinal symptoms and even death.

I've been diagnosed with (by stool test) and been treated for 'overgrowths' (excess amounts) of bacteria like Klebsiella and Enterobacter Cloacae, as well as fungus like candida, and one parasite (cryptosporidium). I also spent the last year treating a dangerous c-diff infection.

NONE of those infections 'made' me gain weight. However, I felt awful enough to throw up at times. I also wanted to eat to comfort myself for feeling physically bad. However, I've worked hard during the past 7 years to become a 'normal eater'. So I've learned to eat when I'm hungry and stop when my stomach indicates comfortable fullness, despite all the intestinal symptoms and illnesses.

No matter what researchers observe with 'mice' experiments, human beings can still choose to eat to cope with their emotions or they can choose to eat when they feel physically hungry. In my experience intestinal bugs (bacteria, parasites or fungus) can make eating less desirable. So I didn't gain a lot of weight. However, many people with candida overgrowth tend to crave and eat more sweets, which can influence weight gain. Obviously further 'research' about how intestinal 'bugs' affect humans is necessary.