4 ms·

This strikes me as a classic place to consider whether this link is a correlation or a causation. It's really easy for me to imagine that diets likely to produc

This strikes me as a classic place to consider whether this link is a correlation or a causation. It's really easy for me to imagine that diets likely to produce a great deal of body fat also produce a home for particular sorts of gut bacteria. It's less obvious, but it's also not such a stretch to imagine mechanisms for positive feedback, in which some of these bacteria reinforce chemical signals that lead to consumption of more of the food they thrive on.

dragonwriter 10y ago
It's also not anything of a stretch to imagine that since gut bacteria are known to play a role in digestion, variations in them might effect the body's utilization of what is consumed.
- neximo64 10y ago
  Its also that while breaking down foods, some bacteria can provide chemicals as by products that indicate to one that they are full. It's perhaps not as clean cut as simple the efficiency of one's biology.
neximo64 10y ago
There have been studies that show stool transplants can suddenly cause massive weight changes in individuals. As is often the case with treatments to IBS. It matches up a lot with this study. In addition a similar study has been tried on genetically identical twins. The difference being the bacteria. How someone cultivates these bacteria, still a mystery. It could be antibiotics as much as potato starches.
- semi-extrinsic 10y ago
  I'd take any study based on IBD data with a large pinch of salt before applying to the general population. Anything that improves the state of the colon for a person with IBD/Crohn's/UC will cause a massive weight change. A few years back I had 30 cm of small intestine removed and promptly gained 20 kg in two months (which was a very good thing for me then). That obviously won't happen to someone normal.
- vanderZwan 10y ago
  > There have been studies that show stool transplants can suddenly cause massive weight changes in individuals. Which is weird, because: > "The researchers found the strongest links with visceral fat, participants with a high diversity of bacteria in their faeces had lower levels of visceral fat." A stool sample decreasing biodiversity sounds counter-intuitive to me
  - pygy_ 10y ago
    The host's flora is wiped out with antibiotics before the transpant occurs. Also, diversity has "the strongest links with visceral fat", it isn't the only parameter linked with obesity (visceral or not).
  - montecarl 10y ago
    If a new bacteria can out compete the others out of existence, then it makes sense.
  - neximo64 10y ago
    The 'bad' bacteria compete for resources with the 'good' bacteria and simply dominate them to starvation to a point of insignificance. All that's needed is a stool sample with a quorum.
  - gr33nman 10y ago
    The "massive weight changes" from stool transplants are most often weight loss, to my knowledge. If so, this would be consistent with increased biodiversity (from the stool transplant) correlating with reduced visceral fat. At any rate, the interaction is probably more complex than our current understanding, as this is a very new area of research.
    - deleted 10y ago
      [deleted]
    - DougWebb 10y ago
      It works both ways, but once people doing FMT realized that transplanting feces from an obese person to a thin person makes the thin person gain weight, they stopped doing that. All of the stool banks now screen for obesity and won't accept donors with high BMI. So now you should only see weight loss after FMT, or no significant change.

dragonwriter 10y ago

It's also not anything of a stretch to imagine that since gut bacteria are known to play a role in digestion, variations in them might effect the body's utilization of what is consumed.

neximo64 10y ago
Its also that while breaking down foods, some bacteria can provide chemicals as by products that indicate to one that they are full. It's perhaps not as clean cut as simple the efficiency of one's biology.

neximo64 10y ago

There have been studies that show stool transplants can suddenly cause massive weight changes in individuals. As is often the case with treatments to IBS. It matches up a lot with this study. In addition a similar study has been tried on genetically identical twins. The difference being the bacteria. How someone cultivates these bacteria, still a mystery. It could be antibiotics as much as potato starches.

semi-extrinsic 10y ago
I'd take any study based on IBD data with a large pinch of salt before applying to the general population. Anything that improves the state of the colon for a person with IBD/Crohn's/UC will cause a massive weight change. A few years back I had 30 cm of small intestine removed and promptly gained 20 kg in two months (which was a very good thing for me then). That obviously won't happen to someone normal.
vanderZwan 10y ago
> There have been studies that show stool transplants can suddenly cause massive weight changes in individuals. Which is weird, because: > "The researchers found the strongest links with visceral fat, participants with a high diversity of bacteria in their faeces had lower levels of visceral fat." A stool sample decreasing biodiversity sounds counter-intuitive to me
- pygy_ 10y ago
  The host's flora is wiped out with antibiotics before the transpant occurs. Also, diversity has "the strongest links with visceral fat", it isn't the only parameter linked with obesity (visceral or not).
- montecarl 10y ago
  If a new bacteria can out compete the others out of existence, then it makes sense.
- neximo64 10y ago
  The 'bad' bacteria compete for resources with the 'good' bacteria and simply dominate them to starvation to a point of insignificance. All that's needed is a stool sample with a quorum.
- gr33nman 10y ago
  The "massive weight changes" from stool transplants are most often weight loss, to my knowledge. If so, this would be consistent with increased biodiversity (from the stool transplant) correlating with reduced visceral fat. At any rate, the interaction is probably more complex than our current understanding, as this is a very new area of research.
  - deleted 10y ago
    [deleted]
  - DougWebb 10y ago
    It works both ways, but once people doing FMT realized that transplanting feces from an obese person to a thin person makes the thin person gain weight, they stopped doing that. All of the stool banks now screen for obesity and won't accept donors with high BMI. So now you should only see weight loss after FMT, or no significant change.