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Comment by teilo | Hacker News Reader

It is true that ketosis is more than low carb, but Gluconeogensis has absolutely nothing to do with it. There is a lot of wrong information out there about GNG.

GNG is an on-demand production of glucose, and absolutely does NOT kick the body out of ketosis, or cause the brain to run on glucose. GNG provides enough glucose for the tissues that cannot run on ketones (such as the kidneys). Without GNG, ketosis would not be possible. In fact, ketones regulate GNG, and prevent it from exceeding the needed maintenance levels.

Furthermore, GNG runs at mostly a constant level, does not increase with protein intake, and is at that constant level even when the body is not in ketosis.

What prevent ketosis in stubborn cases? Insulin resistance. To overcome insulin resistance it takes a strict low-carb regime paired with moderate fat intake, and lowering of stress. The process can be dramatically sped up with intermittent fasting.

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Thank you! I see claims all the time that eating too much protein will kick you out of ketosis, without any actual science to back it up.

>GNG is an on-demand production of glucose, and absolutely does NOT kick the body out of ketosis, or cause the brain to run on glucose.

I never said GNG kicks people out of ketosis, I said protein to fat ratios will prohibit ketosis. Yes, in ketosis your body continues to produce minimal amounts of glucose, I never said anything to the contrary.

However, GNG has a lot to do with ketosis vis-a-vis protein to fat ratios, protein to fat intake can not be to high or it will kick you out of ketosis because of GNG

>Furthermore, GNG runs at mostly a constant level, does not increase with protein intake, and is at that constant level even when the body is not in ketosis.

If you over consume fat or carbs, they get stored as fat in fat cells. What happens when you over consume protein? Protein can not be stored as fat, it must first be converted to glucose, which the body will try to burn before it is stored in fat cells. This is why a high protein to fat ratio carnivore diet will prohibit ketosis or kick one out of ketosis, unlike a high fat to protein carnivore diet (again I never said the body stops producing glucose from protein in that situation, but the glucose production is minimal in ketosis because of the ratios and ketones remain the primary fuel source).

>To overcome insulin resistance it takes a strict low-carb regime paired with moderate fat intake, and lowering of stress.

While generally true and correct, I can even come up with examples where this breaks down...whey oxalate being a perfect example. Whey oxalate will typically have 25g of protein and may have as low as 1 gram of carbs, but Whey oxalate will spike insulin in most people and throw most people out of ketosis.

> If you over consume fat or carbs, they get stored as fat in fat cells. What happens when you over consume protein? Protein can not be stored as fat, it must first be converted to glucose, which the body will try to burn before it is stored in fat cells.

No, this is wrong. GNG is capped in the body, i.e., strictly regulated. It does not increase based upon protein intake beyond that cap. Excess protein is neither converted to glucose, nor excreted. It is utilized in protein synthesis and increases lean body mass.

This has been demonstrated in a number of studies. For example, in Bray GA, JAMA 2012, subjects were fed an excess of 1000kcal over their their maintenance calorie needs for 8 weeks. There were three groups: low, moderate, and high protein. Carbs were constant. Fat made up the difference in caloric content, such that the high-protein group (230g a day) received the lowest fat intake. All three groups gained similar amounts of fat over those 8 weeks, with the high protein group gaining slightly less fat. But the medium and high-protein groups gained lean body mass to make up the difference.

So in short, excess protein is not converted to fat via GNG, but is used for protein synthesis, and increases lean body mass.

> This is why a high protein to fat ratio carnivore diet will prohibit ketosis or kick one out of ketosis, unlike a high fat to protein carnivore diet.

This absolutely does not happen, and I have the blood tests to prove it.

>excess protein is not converted to fat via GNG, but is used for protein synthesis, and increases lean body mass.

>In conclusion, after a high-protein diet, GNG was increased... https://www.cambridge.org/core/journals/british-journal-of-n...

Just reading the abstract makes it pretty obvious.

> "A total of twenty-two healthy subjects (ten men and twelve women: age 23 (sem 1) years, BMI 22·1 (sem 0·5) kg/m2) received an isoenergetic high-protein (30/0/70 % of energy from protein/carbohydrate/fat) or normal-protein diet (12/55/33 % of energy from protein/carbohydrate/fat) for 1·5 d in a randomised cross-over design"

It wasn't the increase in protein that stimulated GNG. It was the reduction of carbs. Without sufficient dietary carbohydrate, the body must maintain minimum glucose levels via GNG.

GNG increases when in ketosis, but is still capped because ketones regulate the GNG process. That is the effect which was observed here. It says it right there in the synopsis:

"Glucose concentration was lower (4·09 (sem 0·10) v. 4·89 (sem 0·06) mmol/l, P < 0·001) and β-hydroxybutyrate concentration was higher (1349 (sem 139) v. 234 (sem 25) μmol/l, P < 0·001) after the high-protein compared with the normal-protein diet."

β-hydroxybutyrate is a ketone body.

Note that this contradicts your statements that GNG will kick you out of ketosis. It absolutely will not.

To repeat: GNG is constant, regulated by ketones, and its relative level is not driven by protein demand, but by glucose depletion.

>Note that this contradicts your statements that GNG will kick you out of ketosis. It absolutely will not.

Its really simple, eat nothing but chicken and/or turkey (high protein, low fat, no carb). You will not become keto adapted or fat adapted.

Alternatively enter into nutritional (dietary) ketosis with a high fat diet, then switch to chicken and/or turkey only (high protein, low fat, no carb) you will not remain in ketosis.

Do you disagree with that? Have you seen any study that shows fat/protein ratios are immaterial to nutritional ketosis?

I'm not aware of any dietary fat requirement to enter or maintain ketosis. I've talked to others that mention a protein/fat ratio but I've not see any literature about it. Citation appreciated.

A low carb and low fat diet is unhealthy for lean people because fat/fatty acids/etc is required for a whole lot of synthesis.

Yes I disagree with that. Dietary fat is not required to enter ketosis. On a lean protein diet, you will indeed go into ketosis, and your body will start using its own fat reserves to produce ketones. However, the transition to ketosis will be more difficult.

In fact, the biggest mistake keto dieters make is to assume that "fat doesn't make you fat". That's just wrong. On any high-fat keto diet you will burn dietary fat before burning your own fat. If weight lost is one's goal, it is essential to limit fat intake to moderate levels, just enough to keep you sated, so that the body is using its own fat reserves.

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