Low carb vs Keto

(Joey) #41

Yeah, well then definitely ditch the “low protein” hypothesis!

(Michael - When reality fails to meet expectations, the problem is not reality.) #42

I did not say ‘never’, but most of the time. Simply because during glacial maxima of the Pleistocene plant availability was limited, even in tropical/subtropical Africa, and its nutrient quality low due to high cellulose content. During glacial minima (like the current Holocene) plant availability was greater, similar to now: limited by seasonal and geographic constraints, but its quality still low due to cellulose content. Aside from some berries and some nuts/seeds, plants provided very limited nutrition until our recent ancestors domesticated some and began selectively breeding them to what we know today. At some point, humans discovered honey with the highest digestible carbs and zero cellulose. Soon after they discovered ethanol.

(Joey) #43

I’ve always tried to maintain a healthy skepticism regarding certain prehistoric details as often asserted by anthropologists, geologists, and bio-historians. Having earned several undergraduate degrees in environmental science decades ago, it seems that accepted details among academics about prehistoric conditions have already changed several times in the intervening years.

If nothing else, consider this: In a freezing cold place where plant life were sharply limited, wouldn’t plant-eating (ruminating) animals also be in short supply? If so, shouldn’t this make us wonder how predators (viz. our human ancestors) could survive in the absence of both edible plants and sufficient prey.

Of course since I wasn’t there I’ll never know for sure. :wink:

(Michael - When reality fails to meet expectations, the problem is not reality.) #44

Many types of plants that ruminants can eat/digest and convert into edible protein/fat for us are available through even very cold winter. Snow cover is a more a limiting factor. Also, most animals are able to fatten up during the growing season because they can digest cellulose. In the Yukon, for example, where I lived for a decade, moose and caribou were year-round resident. They pretty much ate non-stop for five months. During the remaining 7, they lived off the accumulated fat and augmented as well as they could from whatever cellulose sources they could find. Even rabbits do the same and they store much less body fat proportionally than the larger ruminants. Cellulose doesn’t disappear when plants stop growing during winter. It’s still there and still edible.

(Bacon is a many-splendoured thing) #45

The main benefit of remaining in ketosis is avoiding glycation damage to cells, and in avoiding the various effects of the chronically elevated insulin levels needed to deal with an excess of glucose. Serum glucose elevated above the level maintained by the body in the absence of carbohydrate intake causes damage, which is why insulin mobilises to deal with it.

You appear to be assuming that there is some advantage to eating carbohydrate, whereas the damage done by populations to themselves when they switched from hunting to agriculture is well-known to anthropologists, who can tell a culture’s diet simply by looking at the bones of the people at the site. Dr. Michael Eades has a fascinating lecture on this topic, which can be found on YouTube in several different versions.

(Bacon is a many-splendoured thing) #46

I would say not. Since glucose in the bloodstream above a certain minimal level is toxic, the body mobilises fairly quickly to get it out of the bloodstream and into muscles for glycolysis and into adipose tissue for storage in the form of triglycerides. I can’t see the body permitting interference with those processes. Getting rid of excess glucose is an “all hands on deck” type of operation. So the muscles are pretty much burning either glucose or fatty acids, but not both, and fatty acids are kept locked up in the adipose until insulin drops low enough to let them out again.

(Joey) #47

@PaulL I’ve got great respect for your knowledge and guidance on this forum. And while your comment above sounds reasonable on its face, I struggle to imagine how our bodies - equipped to operate in more than one metabolic mode - necessarily operate on either glucose or ketones, but never any blend of both at the same time.

Frankly, I thought that - even while producing ketones - our bodies engaged in gluconeogenesis at the same time. But if our muscles can only utilize one or the other, why release both into the bloodstream simultaneously? How certain are you that this is a binary (all or nothing) thing?

Question: If indeed there’s some instant in time when our muscles go from utilizing 100% glucose and 0% ketones, to then suddenly utilizing 100% ketones and 0% glucose, what’s the mechanism that signals all of the muscle cells throughout our body to be so well coordinated as to switch over in unison? Perhaps some precise concentration of insulin in the blood (evenly distributed throughout our blood serum) such that all our muscles respond in lockstep? Does this seem likely at the molecular level?

Any scientific support you might point to that supports the characterization of a “never both” hypothesis would be much appreciated. Thanks!

(Michael - When reality fails to meet expectations, the problem is not reality.) #48

@PaulL @SomeGuy check out my reply re RER above:

(Bacon is a many-splendoured thing) #49

Well, in a sense what you are talking about is true all the time, because your red blood cells need glucose, because they cannot metabolise anything else. Which is why the liver produces glucose (gluconeogenesis) when we eat very little carbohydrate. Along with ketones (ketogenesis), of course.

But when we eat enough carbohydrate to raise our blood glucose to potentially harmful levels (and remember that anything above the bare minimum needed to feed the red blood cells and a few others is potentially harmful), then the rise in insulin shuts off ketogenesis and gluconeogenesis and forces the muscles and any other cell with insulin receptors to take in glucose, so as to get it out of the bloodstream. If the muscles didn’t give priority to metabolising the glucose, they would quickly get clogged with it, which causes them even more damage than metabolising the glucose causes (this is the reason for keto-adaptation: the muscles need to heal from the damage done to them by metabolising all that sugar, before they can readily return to metabolising fatty acids). Muscles, after all, cannot store the vast quantities of glucose in the form of triglycerides, the way fat cells can.

Why is it so important to you for the body to not give total priority to getting rid of glucose when it needs to? Don’t let sixty years of misguided dietary advice prevent you from thinking clearly on this topic.

(Joey) #50

I’m in full agreement that muscles need time to recover; which illustrates my point… it’s not an instantaneous event. The process of “fat adaption” can take weeks/months. Which strongly suggests that one is not in either ketosis or glycolysis during this stage (… perhaps ever?)

:grey_question::man_shrugging: Please recognize that it’s not important to me personally that the body do anything in particular. As for thinking clearly, I’d like to think my effort to understand is helping - not preventing - clearheaded thinking, and I invite others to join me in the effort.

“Total priority” (as you’ve termed it) to a single metabolic pathway - fully shutting off alternative pathways to get vital ADP into various cell types - still sounds pretty extreme to me. All the more so given that our bodies are well-equipped with more than a single way to stay alive.

In short: the characterization that it’s “all-or-nothing” seems cartoonish to me.

So I’m left asking whether there’s clear science to support this view? If not, no worries. But then let’s just acknowledge that the science has neither confirmed nor rejected our respective views.

(PJ) #51

I have never had a glucose and ketone measure that did not have some of both.

(Ken) #52

Here’s a different take on this subject. Keto doctrine and dogma is based on daily macros. What I figured.out many years ago is that is simply Dogma. Since reactions to nutritional consumption is based on chronic patterns and.consequential adaptive hormonal reactions, a longer term view is more appropriate. For example, if.we.use the.60/35/5% Paleo Whole Animal macro and extend it to a week, you can see what I mean. It means protein and.fat mainly, but eating your entire.allottment of carbs (5% of total calories X 7 days) by having.them split/consumed in only one or two times per week rather than daily. This covers the metabolic flexibility issues.

What really happens to enable people eating low carb is that eventually they deplete glycogen and burn stored body fat, but every time they eat carbs the process stops. When the carbs are.gone lipolysis resumes, so it’s more of an intermittent process. Same type things happens when following carb based semi starvation, but the duration of actual fat burning may be.fairly short depending on calories.consumed. A very crappy way to lose.fat, I look back to when I practiced it and.cringe.

(Jane) #53

Me too.

(Bacon is a many-splendoured thing) #54

No, during the adaptation phase, the muscles are limping along, metabolising ketone bodies from the liver. One’s metabolic state is determined by the amount of carbohydrate eaten and the resulting level of serum glucose. A high level of glucose prevents gluconeogenesis and ketogenesis, because of the need to get the toxin out of the bloodstream. A low level of glucose actually requires gluconeogenesis and ketogenesis, so that the brain and other organs can be properly fed. It’s pretty much an either/or situation, for reasons that will become clear if you think about it. When there is a crap-ton of glucose in the bloodstream to be gotten rid of, you don’t want your liver to be making even more glucose, nor do you want it to be producing ketone bodies to compete with glucose for metabolism, since the whole point is to get rid of the excess glucose as quickly as possible. This is why the metabolic pathway in use is either one or the other, not both.

The skeletal muscles actually prefer to use fatty acids, however, so when they have finally adapted to fatty-acid metabolism, they stop using ketones and will actually refuse to take in glucose, if possible, so as to spare it for those tissue that absolutely must have glucose. On the other hand, the heart muscle absolutely thrives on ketones, especially if there is any damage to it or to the coronary arteries, because ketones require less oxygen than fatty acids to produce the same amount of energy.

If you’d like to know more about these metabolic effects, you might enjoy reading the papers by Yalow and Berson on the effects of insulin on the metabolism.

(Joey) #55

@PaulL I’m afraid we’ve reached the point where we’re repeating ourselves…

I keep questioning your assertion it’s an all-or-nothing situation and ask for scientific support. You keep telling me it’ll become clear if I think about it - now asserting that since our bodies must want something, they necessarily get it.

Thanks for this suggestion: I tried to find Yalow or Berson papers (PubMed) to find science on this specific topic - so far I came up dry. Will scour a bit more to see if I can identify anything relevant to the question at hand.

Meanwhile, thank you for your time and patience in trying to address my question. I’m clearly not convinced (yet) that the body is either in 100% ketosis or 100% glycolysis - and no, it’s not for lack of thinking about it. But I strive to keep an open mind and will be convinced by relevant evidence.

Cheers!

(Chris Kornelsen) #56

Why is sugar considered a toxin? When our bodies clearly need glucose to survive. Not outside means but we do need glucose. It cant be a toxin then. Toxic at high levels for sure. But just to be labeled a toxin seems pretty extreme? Many people around the world thrive on 150g and under carbohydrates. My grandparents died at 89 and we are germans so tons kf bread and butter soups and patatoes and meat. Toxin just seems to be a little on the extreme side?

(PJ) #57

I think something can have a somewhat toxic effect but be “well worth it” in a given situation. Meat, for example, is a big hella hard digestive process, but well worth it, but just wait till you hear a vegan describe the process. :rofl: Sugar is actually a hepatic toxin, but it’s a dose-dependent situation. Small amounts of it aren’t – or rather they are, in terms of they have the effect, but the liver has no problem handling that dose.

It’s the large amounts (and the chronic amounts, and the combination) in our culture that make it toxic, because of the dose. Even vitamins and minerals that we need desperately and constantly or we sicken and die, can become toxic at a certain dose.

(Michael - When reality fails to meet expectations, the problem is not reality.) #58

My earlier post:

The RER table in my above post seems to support your contention that fat and carb burn can/do occur simultaneously over the full range. Yet it remains to be demonstrated whether or not reality conforms to the sliding scale math. Hopefully, I can add some helpful data once I have possession of a Lumen.

That said, we know that for each individual there is a concentration of glucose/insulin that effectively inhibits gluconeogenesis, ketogenesis and lipolysis. So above some concentration we could reasonably expect little or none to occur. Effectively an off switch.

The converse, however, is not the case. Since some cells require glucose (red blood, for instance) there must always be some glucose. Preferably from gluconeogenesis rather than carb consumption. This concentration of glucose/insulin is low enough not to inhibit ketogenesis and lipolysis generally.

So I imagine the Lumen will never indicate 100% fat burn. It might, however, indicate 100% glucose burn. My understanding currently is that one must engage in very vigorous physical exercise to generate an RER value of 100% glucose burn. But this is based on people eating a SAD diet that always includes a combination of both carbs and fats.

I wonder what the Lumen will indicate if I eat a day of carbs sufficient to spike my glucose/insulin above my ‘trigger point’ to stop fat burn. 2 or 3 large DQ vanilla cones would probably do it. What sacrifices I make in the name of science. :sunglasses:

See my initial discussion of RER if you want to review the equations.

(Joey) #59

@amwassil Such sacrifices … a true pioneer! Will make time to explore the RER table/equations and Lumen info in more detail sometime soon. Thx.