Overfeeding Changes Gut Bacteria Which Become 'better' At Harvesting Energy...

dazdaz today is a good day ✭✭✭
edited July 2016 in Gangster Banter

How's this one for your gut bacteria giving you the finger...

There are a few studies & articles on this topic, a google of something like 'firmicutes bacteroidetes energy harvest' gives you a good selection.


one article reads; "It has been shown that the higher your energy intake is above that required to maintain your weight, the greater the increase in Firmicutes and the decrease in Bacteroidetes in your gut flora. This results in more calories being extracted from the food you consume rather than lost in your stools, making it harder to lose or maintain your weight."


From a 2001 study:

"Results: The alteration of the nutrient load induced rapid changes in the gut microbiota. These changes were directly correlated with stool energy loss in lean individuals such that a 20% increase in Firmicutes and a corresponding decrease in Bacteroidetes were associated with an increased energy harvest of ~150 kcal. A high degree of overfeeding in lean individuals was accompanied by a greater fractional decrease in stool energy loss."


If you didn't quite grasp that quote; it is basically saying that if you overeat (overfeed), your gut bacteria will alter (more firmicutes, less bacteroidetes) and get more efficient at extracting energy (calories) from the food you eat, to the extent of harvesting/extracting an extra ~150 cals per day from your meals. 


(in some ways, you would have thought it should have been the other way round...eat less, and the gut bacteria become more efficient extracting calories. but life aint always fair).

fake it till you make it


  • ACH85ACH85 ✭✭
    edited February 2015

    Ehh... interesting, but I don't think it tells the whole story. 


    They're measuring decreased kcal output in terms of poop, not what's going on with those calories. The energy harvested by bacteria does not necessarily get passed on to us, and certainly not at a 1:1 ratio. Perhaps it solely fuels additional bacterial growth? Perhaps, as in the case of gorillas eating fiber, it is fermented into beneficial short-chain fatty acids at a 4:1.5 calorie ratio. (The bacteria in gorillas get 2.5 kcal, and provide 1.5 in short chain fats to be absorbed by the gorilla.) 


    Besides, dietary changes result in gut biome changes in as little as 48 hours, so it shouldn't be all that hard to address any issues. 


    Plus... is losing calories in your poop really supposed to be a good thing? Sure, maybe if you've just eaten McDonald's, but I'd think most of us here would agree that efficient digestion involves getting the most usable calories and nutrients out of our food before we poop it out. 

  • dazdaz today is a good day ✭✭✭
    edited February 2015

    yeah, wasn't too sure about this ins & outs of this one myself. hence i stuck it under 'Gangster Banter'.

    & a lot (if not most?) of the related studies have been done on mice (not humans).

    but interesting stuff never the less, i'm sure we will hear more.

    fake it till you make it

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