Monday, June 21, 2010

Are the Bacteria in Your Colon Influencing Your Body Weight?

This is no joke...most of the cells in your body are not your own....they are from bacteria (bacterial cells are much smaller than human cells).  Most people have about 500 to 1000 different species of bacteria living in their body at a given time.  Some of these live in your eyes, mouth, nose, etc...but most of them reside in your colon.  

In fact, it's quite a party down there!  Most of the bacteria received an e-vite for your colon party shortly after you were born.  A few others were invited later because of what you ate or where you went on vacation or where you lived.  But no matter when and how they got there, they pretty much fall into two categories: The 'A-listers', those that you want at the party, and the 'party crashers', those that just cause trouble and you want them to mellow out or just leave.  If the party crashers somehow gain control of the party, things go south resulting in pleasantries like diarrhea, constipation, or even colon cancer.

It used to be easy to decide who was an A-lister and who was a party crasher based on whether the bacteria kept your colon functioning healthy.  But like science tends to do, it's become a bit more complicated.  A few years ago, a study in mice showed that those without any bacteria in their colons (aka, sterile) grew up to be lean whereas those that had a whole bunch of bacteria grew up to be fat.  A little bit more science happened and those mice with certain classes of bacteria turned out to be thinner than other mice with different bacteria (and it wasn't always the 'party crashers' that caused weight gain). 

You see, bacteria survive down there by eating the leftover carbohydrate that isn't digested and absorbed into your body sooner (and in eating the carbohydrate, they produce methane this ringing a bell?)  Some bacteria are better at eating up all of the leftover carbohydrate than others.  By munching on the leftover carbohydrate, they liberate the calories that would have otherwise passed right on through into the bowel.  More carbohydrate-eating bacteria = more calories in your body.  Less carbohydrate-eating bacteria = less calories in your body.  How many calories are we talking about?  Not yet known.

So do obese people have certain bacteria in their colons that make it harder for them to lose weight and keep it off?  Maybe.  Several Dr. Dorks seem to think so and are trying to conduct the studies to figure it out.  But it's a bit complicated by the fact that there are so many different species living down there.  Chances are, it's not going to be just one that is responsible for weight gain or weight loss.  And maybe there are certain bacteria that eat up a lot of carbohydrate (that might lead to weight gain) but are really good for reducing your risk for colon cancer?  Alas, it's not going to be simple to figure this all out! 

What is SHE to do?  At this point, I would do absolutely nothing except use this information to impress your friends.  Colon-Speak makes for great conversations at intimate gatherings.  "Do bacteria or cockroaches rule the world...discuss". 

I'll keep my readers (all 8 of you) posted on any new findings related to this. Should be an interesting few years to see how this all shakes out!     


  1. How timely!!! I presently have some party crashers racing for the exit thanks to my family sharing a few stray bacteria - a sort of Wisconsin Dells in the bowels if you will... So tell me Doc - when there is a massive migration toward the exit like this, am I losing some of the bad and is it an opportunity to re-engage with the friendlies? If so, what should I do / eat to be hosting the best party I can? And no, this is not a Brick Tamland pants party...(reference from Anchorman, which may be the best comedy movie ever made).

  2. I love your blog - it's so informative and helpful!! I have a website,, and would love to hear from you! ShareWIK (share What I Know) is a website devoted to bringing together women from all different situations and backgrounds (as well as a few men!) to talk about their experiences and learn from each other. We have a group on ShareWIK called "Weight Loss/Body Image" as well as one called "Nutrition Supplements" that could really use your input. Hope to hear from you!
    - Diana Keough
    P.S. Heres the link to the group. Just sign in to get started!
    Weight Loss:
    Nutrition Supplements:
    And keep up the great work!

  3. Thanks Diana! I will check it out. :)

    And B. Frank... there are a few things you can do to re-populate your party. Yogurt with active cultures, fruits, vegetables, and whole grains (particularly those higher in fiber) will win over your A-list guests. Some folks swear by products that contain probiotics (like Activia yogurt, some supplements, Kombucha tea), but you need to use these with caution. For some folks (me), methane is produced at astronomical levels. You will know in the 30-120 min period following eating whether or not you're "one of those".

    And I would agree that Anchorman is one of the best comedies every made. "I love lamp"

  4. Not being a Doctor, I'm confused by all the bio tech talk here but I think your chatting about something that may help me. I recently had my gallbladder out and my body went haywire to the point that my nerve endings were vibrating on high-along with a host of other weird happenings. After trying several things, what I found to help was loads of probiotics. But I can run a smart car with my gas and I have gained 60 pounds in 6 months while only eating 1000 calories a day of: fresh veggies, whole grains, fruits and nuts. I also drink green tea and water only. I exersize a minimum of 40 minutes a day. My male Doctor doesn't believe this is possible. Any suggestions? e-mail me at: