John Wagner:

"am I right in the the assumption that gut flora is relative to our intake of carbs?"

No.  That's a misrepresentation currently promulgated by Tim and (primarily) Richard, for reasons I can't begin to speculate on. 

Our population of gut flora is relative to our intake of food that we can't digest or absorb — but that the gut flora we have can digest and absorb. 

The bulk of this involves what is called "soluble fiber" on the nutrition label — complex molecules like inulin that we have no enzymes to break down.  "Resistant starch" is an outlier in that it's considered a "carbohydrate", and shows up as carbohydrate on the nutrition label, even though we can't digest it.

However, cheetahs have gut flora that can digest collagen, cartilage, glucosamine and chondroitin (Depauw 2012) — so I see no reason to suppose humans couldn't, either.  People with fructose malabsorption, or who drink giant sodas (we can only absorb so much fructose at a time) usually end up with a lot of gut flora that eats fructose — again, because anything that makes it out of the small intestine is either fermented by gut flora or pooped out.  And so on.

The gymnastics that the RS brigade has to go through to get any significant amount of RS in their diet using anything but the potato starch hack, compared to the amount of regular carbohydrate in the starchy foods they're eating (selecting only a few foods, preparing them carefully with multiple cycles of heating and cooling) tells me that RS alone is not generally a significant contributor to prebiotic content in any natural human diet compared to regular old non-sexy soluble fiber, found in every fruit and vegetable.

And vegetables are most definitely low-carb.

There is another irony: the way you get "low net carbs" in low-carb bread and other junk is by using a lot of…SOLUBLE FIBER, which (according to the rules) you subtract from the carb count.  So low-carb junk food is, ironically, usually quite high in prebiotics…much higher per calorie, and often in general, than the carb-heavy foods being recommended!

There's more baloney here: their entire idea that low-carbers are dropping dead of gut inflammation and permeability is based on one anonymous commenter.  Then there's the idea that you can diagnose remotely, over the Internet, the degree of systemic inflammation based on two crappy cell phone photos in radically different lighting…that look the same anyway.  (There are cheap and easily available medical tests for that, like CRP and hsCRP.)  And Richard has been relentlessly deleting the comments of anyone who dares to point that out — or to disagree with RS dogma in other substantive ways.  It's easy to manufacture consent when you simply vanish those who disagree.

I'm also seeing clear misrepresentation of science, both at FTA and from the American Gut Project, who are clearly Pollanesque guilty vegetarians looking for excuses to bash meat-based diets.

Anyway: The important thing to remember is that there is a lot we don't know about gut flora, and most of the conclusions I'm seeing drawn are either wrong or extremely premature.  We don't even know which bugs are good and which are bad!  For instance, we used to think the Bacteroides/Firmicutes ratio was a predictor of obesity…turns out that's not true.  Michael Pollan is proud because he has a lot of Prevotella from his grain-based diet, as do African children, and they're all thin, right?  Turns out Prevotella is a strong risk factor for rheumatoid arthritis. 

I forget who said this, but it's a truism: the number of plausible hypotheses is inversely proportional to how much we actually know about a subject.  Since we know so little about gut flora, it's possible to make almost any argument.  (For a contrasting view of gut flora, see Petro's posts on FIAF (1) (2)…and recall that sterile mice, e.g. mice with no gut flora, are slim on diets that make regular mice obese.) 

As for myself, I'm not jumping on any bandwagons until I understand the science enough to be secure in making recommendations.  That's why I haven't gone through multiple dietary-religious conversions, bounced between crash diets, or had to make any substantive changes to Eat Like A Predator over the years since I wrote it.  

Yes, you can certainly experiment with the potato starch hack, because it's cheap and easy: I did, too!  But don't be surprised if it makes you fart, makes you fat, destroys your motivation (too much serotonin is just as bad as too little), stops working after days or weeks, or does nothing at all: these results have all been reported.  The flip side of "more gut bugs than cells in your body" is that the response of your gut biome to dietary changes is at least as individual, possibly more, than the response of your body to dietary changes. 

And "OMG YOU'RE DOING IT WRONG AND EVERYONE IS DEFICIENT IN THIS THING ONLY FOUND IN MEANINGFUL QUANTITIES IN PREPARED NEOLITHIC FOODS" is provocation marketing, not science.

JS

PS: Because drama is so popular on the Internet, let me add this clarification. 

I like Richard and consider him a friend: we've shared meat and alcohol, and we've been guests in each others' homes.  This is a factual disagreement, not a personal one.  Besides, he's a big boy and I know he can take it as well as dish it out

Paul:

Thank you.  I do my best to separate hype from science -- and while there's definitely some fascinating stuff in there, we're so early in the gut biome game that it's tough to give any recommendations without seriously overreaching the data.

Jules:

I picked up a kidney stone early in my Paleo transition.  The solution for me was to drink lots and lots of water until I passed it, which happened soon afterward.  Interestingly, the stone hasn't recurred, despite my diet being as meat-heavy as before...I'm not sure why.

"yet I've eaten far more fruits and veggies then I ever did before I ate Paleo."

Absolutely!  I've found the same to be true.  Clearing the bread and empty starches out of your diet leaves a big vacuum that has to get filled with something.

Alex:

Any quantity of PS over 1 TBS gives me horrendous gas: I have no idea how people are taking 5+ TBS! 

1 TBS usually improves my sleep the first night or two: it feels a lot like a high dose of melatonin.  However, after a few days I start feeling the effects of what I believe to be too much serotonin -- a total lack of motivation that feels a lot like depression without the despair.  This is a robust result that has happened on multiple occasions, and people report similar effects from SSRIs, so I'm reasonably sure this is what's going on.

I haven't tested my fasting blood glucose yet, though I expect I'll get around to it eventually.

JS

Minerva:

If you're eating paleo foods, it's less important to be concerned with exact ratios.  I wrote ELAP the way I have, because Fear of Meat and Fear of Cholesterol are so heavily ingrained in us that it takes some deprogramming to get past them!

That being said, there are still potential problems.  A lot of people get stuck in "lean muscle meat and broccoli" land, which is great for short-term weight loss but tends to crash you in the long term, especially if you're active.  It's important to be realistic: paleo works great, but weight loss stalls occur on any diet, diet can't solve every medical problem by itself, and a sufficiently limited food palette can result in deficiencies even if the individual components are relatively nutritious.

Most importantly, as I note in the disclaimer on my sidebar, "Your life and health are your own responsibility."  Yes, I believe that "listening to your body" usually works well once you're past the initial stages of cravings, which is why it's part of a step in ELAP -- but no one but you can decide what tradeoffs are best for you.

JS