KETwhOle30

[kirkor]

Ahahahah!

If Meat Eaters Acted Like Vegans:

(same guy that did the "How To Become Gluten Intolerant" video I posted in this thread)

[kirkor]

Since the term "fat adapted" gets used a lot re: Whole30, I thought this exchange at another forum I frequent was a useful one:

Must we send our DNA to "fat adaption" school?

Q:

The term “Fat Adapted” has never gelled with me. It is like saying we are “oxygen-adapted.” With enough training could we become water adapted like fish?

Must we “teach” our bodies over a period of weeks to properly burn fat? Once we are out of glucose, shouldn’t we burn fat without the need for proper training? Is it possible that being fat adapted is more of a psychological state rather than a physiological state? 

If someone deeply understands the physiological mechanics behind the theory of keto-adaption, I would love to better understand it. Are we saying that if I have zero glucose reserves that I will burn fat better if I am fat adapted compared to having zero glucose reserves without the proper physiological “fat burning cellular education”?

A:

Pyruvate dehydrogenase activity (the process necessary for terminal oxidation of glucose by mitochondria) is downregulated during carbohydrate restriction, this spares carbon for gluconeogenesis and for necessary 3 carbon inputs towards the krebs cycle. Which means that acetyl-CoA will preferentially come from fat or ketones vs. glucose, if glucose is a source for acetyl-CoA, then there's a net carbon loss for potential glucose resynthesis. Competition by glucose is a major determinant of fatty acid oxidation, as you suggest.

I think the term "fat adapted" originates with Steve Phinney, what he was talking about was a decrease in the ability to do sort of medium intensity endurance exercise, the sort of exertion you might be capable of sustaining for a couple of hours, that came with switching to a ketogenic diet. After six weeks or so in his studies, that ability returned to normal.

Fat adaptation and keto adaptation get thrown around a lot, I think very often not very well defined. If you look at starvation studies as possibly an accelerated model of fat adaptation, that might or might not be valid, but let's do it anyways. Ketone production reaches its peak at 3 days, but blood ketone levels don't reach a peak until ten days or so. Initially, ketones will provide about 25 percent of muscle's energy needs, but by day ten, almost none--that's why blood ketones continue to go up even though ketone production plateaus early on. Muscle burns less ketones, gets more of its energy from fat as time goes by. I've heard Phinney talk about this with nutritional ketosis as well, early on muscle uses ketones, later it's spared for the brain. So once glucose is gone, ketones are still there to compete with fat for oxidation by muscle, further adaptations are necessary for muscle to spare ketones, and fat adaptation is as much an adaptation away from oxidation of glucose and ketones as it is an adapatation towards oxidation of fat. Of course by definition you're still burning fat--the original use of "fat adapted" was more specific to exercise tolerance.

Looked at that way, ketoadaptation--I usually see this defined as the adaptation of the brain to ketones as a primary fuel--is really the result of the rest of the body being reticent enough towards ketone oxidation to spare it for the brain.

[kirkor]

Good analysis of current practices of carnivory: https://optimisingnutrition.com/2018/03/14/dr-shawn-bakers-carnivore-diet-a-review/