Thread by @DaveKeto

1/ Posting this hypothesis for posterity:

I now suspect #PlantBasedLowCarb (PBLC) isn't as low carb as originally thought.

Before getting started in this thread, I should emphasize I wouldn't consider this a good or bad thing in and of itself, but it is of interest, ofc...

2/ Moreover, I've regularly pointed to people following my work who are both (1) very interested in a low carb diet, but (2) would prefer to keep their #LDL low to consider PBLC as a "third option", as I commonly see it associates with this outcome.

Now to my hypothesis...

3/ PBLC generally has two major features separating it from "typical" #keto/#lchf:

1) More fat sourced from mono and polyunsaturated fatty acids (M/PUFA) instead of saturated fatty acids (SFA)

2) A lot more soluble and insoluble fiber via plants

4/ It's generally assumed one can easily achieve being keto on plant-based given blood levels of beta hydroxybutyrate (BHB), a ketone body, tend to be high on PBLC.

But here's the thing, PUFA is very "ketogenesis-inducing" -- (@KetoCarnivore has a lot of material in this area)

5/ There are a number of studies that explore this, such as this one (though not that ideally): academic.oup.com/jcem/article/8…

But this begs an interesting question...can PUFA being more ketogenic actually mislead us into assuming lower glucose, higher fat use than expected for a diet?

6/ In other words, can a diet *appear* to be more ketogenic due to the higher use of PUFA in spite of marginally higher carbs?

I think so.

Remember, BHB (like glucose) is a substrate in the blood...

7/ Like many substrate blood tests, we are measuring that which is in transit, but not yet in use. We can't know for certain what the actual secretion and/or uptake is.

So we don't truly know how much BHB will correlate strongly with actual fat vs glucose use by cells.

8/ Which brings me around to my hypothesis regarding fiber, particularly soluble fiber.

I posit it may appear less glycemic than it is due to a greater use of M/PUFA generating BHB under this PBLC context.

There are two metrics that would help test this...

9/ The first is Respiratory Exchange Ratio (RER). Never mind resident ketone levels in the blood, looking to the aggregate cell respiration itself will certainly give you a powerful metric of what degree a usage each substrate is providing.

10/ The other is a Continuous Glucose Monitor (CGM), which I likewise believe will show marginal, yet detectable changes in my glucose levels.

I plan to do each of these for my coming fiber-only intervention experiment. Should be fun to see how these results play out.

I should cc @nicknorwitz, @Ad_SotoMota, @ScepticalDoctor, and @cadiulus