Greedy Guts: How the Bugs in Your Guts Might Just Make You Fatter

January 16, 2007

Greedy Guts:  How the Bugs in Your Guts Might Just Make You Fatter 

 Competency # 1 Risk                               ReferenceNature 2006 Dec p1022-1023 

 “I don’t get it, I get fat when I eat the exact same food as my friends, and they don’t.”  Heard that before?  Rolled your eyes? Said it was just an excuse.  Well, maybe not so! Here is another story about the bacteria in your intestine!  The research team at Washington University School of Medicine has unlocked another fascinating piece of knowledge about you and just published it in the Journal Nature and the Proceedings of the National Academy of Sciences.  

Some people have bacteria in their intestines that digest more calories for them. Here’s how it works.  Most of us have 90% of our gut’s bacteria in the form of two families, the Firmicutes and Baceroidetes.   The Firmicutes turn out to be able to digest what most of us think of as indigestible fiber.  They turn that fiber into simple sugars.  You absorb the sugar and you get fat.  (Remember the column last year we did about how our guts make us look like a cow.  Well, that’s what those bacteria do in a cow too.)  The less Firmicutes you have, the thinner you are. 

 Now, it’s not quite that simple.  Turns out, if you can lose weight, the balance of the two families changes back to the amount found in skinny folks.  So which came first?  What that does mean is that as we get bigger, the bacteria in our guts change and with that change comes a greater “efficiency”.  It’s like double jeopardy, a slippery slope. The story gets weirder.  The bacteria in your normal gut do more.  

As in almost all biological systems, there are multiple layers of control.  What the researchers found was that the normal bacteria suppress the production of a substance called “fasting-induced adipose factor”.  That helps your body store fat.  You suppress it at your own peril.  They also found a suppressed level of adenosine monophosphate-activated protein kinase.  That makes it harder for you to burn the fat you already have.  This is not Double Jeopardy, it’s Triple or even Quadruple Jeopardy!  Not only do the bacteria make more calories available by making lousy old fiber into digestible glucose, but then they manipulate your own internal genes and make you more efficient in two different ways.  

This is terrible news the month after the Holidays when the average American gained 5 pounds. I used to say, “A calorie is a calorie is a calorie.”  I apologize.  That’s just not true.  For some of us, a calorie is a 110% calorie.  The bigger we get, the higher the number might be.  For those of us who feel like our destiny is to be eternally struggling, at least you have the solace of knowing you were a little bit right.  You can blame it on the greedy bugs in your guts. 

 WWW: What Will Work for Me.   Remember, to lose weight effectively, you do have to eat fewer calories. What Brian Wansink convincingly says in his book, “Mindless Eating” is that we fail when we deprive ourselves and feel deprived.  Just let go of 100 calories here and 100 there and you don’t feel starved, just a touch below normal.  I can deal with a touch.  A hundred calorie battle won each day is a pound a month.  Eat an apple instead of a bowl of ice cream at 8 o’clock when you turn on CSI.  New Years Resolution: lose just one pound a month.

This column was written by Dr. John E. Whitcomb, MD. Brookfield Longevity, Brookfield, WI. (262-784-5300)