Is the “too much protein turns to sugar” a myth?


And we still didn’t get the answer to what happens to excess protein, unless I missed it because I’m a dumb.

or do we?

If you are ketogenic and work up from low protein to moderate proteins you it will be stored as fat, if you are SAD it gets turned into sugar and then stored as fat. IDK

(Terence Dean) #49

I don’t have good references that address your question but excessive protein is not good if you already have dodgy kidneys. Its the nitrogen that seems to do the damage. I’m happy to listen to Phinney and Co and accept their recommendation levels for moderate protein intake as :

1.5 and 1.75 grams of protein per kg of ‘reference body weight’*

Protein levels never bothered me pre-Keto I saw a steak, I ate it. Who gives a fuck right?

Its only since going Keto that we panic about these things. Lets keep our heads buried in the sand like an ostrich its far less stressful!!!



As a T2, I never see a huge spike in my blood sugars when I eat a protein-heavy meal. For example, we had a brunch on Sunday where I had sausages, bacon, shrimp and cocktail sauce, lox and capers and cream cheese, chicken breast, and several steak medallions. And at the labor day BBQ, I took several hot dogs and hamburger patties, with some bacon and chili.

Blood sugar barely nudged.

(TJ Borden) #51

That’s kinda of what I’ve heard too. I know Richard mentioned somewhere around 3 causes ammonia issues?

I’m mostly carinovire (although being hatch chile season, I’ve been having my fair share of them), and I don’t track it at all because I know I’m not actually eating that much. I think the question really is, and there may not be a good answer, say your target is 100 grams of protein, and you have 150. What happens to that extra 50 grams?

It seems generally accepted that the excess can cause an insulin response (although protein on its own still creates an insulin response, just much less of a response than carbohydrates), and some believe it goes towards gluconeogenesis, which might be true, but we also know that gluconeogenesis is demand driven, not supply driven, so simply having excess shouldn’t trigger gluconeogenesis on its own.

To be fair, it may be answered in some of the videos and/or links above… but I’ve been lazy today and haven’t looked :stuck_out_tongue_winking_eye:


If I were doing a therapeutic ketogenic diet to treat a neurological disease/disorder or cancer then I may be concerned with too much protein having a negative impact - the therapeutic diet needs to be very finely tuned. Currently I’m content to stick with Bikman & Naiman :smile:

(Bunny) #53

Good point! :+1:

How I understand this:

Too much protein triggers insulin; when insulin is high IGF-1 goes down![2] Too much IGF-1 is not good either[1] nor is too much insulin! BALANCE?[5]

Human Growth Hormone (the fat burning hormone) is what breaks down fat into ketones by the liver. It is blocked by sugar/glucose, cortisol and less by estrogen[2]?

IGF-1 is very similar to insulin and gets signals from the human growth hormone that tells the liver to start producing it or what is called insulin like growth factor rather than insulin from the pancreas when a certain threshold of carb, protein, fat and sugar intake is adhered too?[5]

Glucagon (it is like insulin) like that explained in the video below[4] can be activated if needed (e.g. a person who is hypoglycemic) and is secreted by the pancreas when a little bit of protein is eaten rather than sugar/glucose.

  1. Glucagon is secreted by the pancreas

  2. IGF-1 is secreted by the liver

  3. Human Growth Hormone HGH is secreted by the pituitary

  4. Insulin is secreted by the pancreas

  5. Omega 3’s DHA (from marine life) regulates somatostatin[1] (e.g. cold thermogenesis activation of brown fat and browning of WAT). Somatostatin regulates or inhibits the production of HGH[1], Ghrelin (e.g. fasting) increases the production of HGH[1]…


[1] Control of Growth Hormone Secretion: Production of growth hormone is modulated by many factors, including stress, exercise, nutrition, sleep and growth hormone itself. However, its primary controllers are two hypothalamic hormones and one hormone from the stomach: image
•Growth hormone-releasing hormone (GHRH) is a hypothalamic peptide that stimulates both the synthesis and secretion of growth hormone. •Somatostatin (SS) is a peptide produced by several tissues in the body, including the hypothalamus. Somatostatin inhibits growth hormone release in response to GHRH and to other stimulatory factors such as low blood glucose concentration. •Ghrelin is a peptide hormone secreted from the stomach. Ghrelin binds to receptors on somatotrophs and potently stimulates secretion of growth hormone. Growth hormone secretion is also part of a negative feedback loop involving IGF-I. High blood levels of IGF-I lead to decreased secretion of growth hormone not only by directly suppressing the somatotroph, but by stimulating release of somatostatin from the hypothalamus. Growth hormone also feeds back to inhibit GHRH secretion and probably has a direct (autocrine) inhibitory effect on secretion from the somatotroph. Integration of all the factors that affect growth hormone synthesis and secretion lead to a pulsatile pattern of release. Basal concentrations of growth hormone in blood are very low. In children and young adults, the most intense period of growth hormone release is shortly after the onset of deep sleep. …” …More

[2] Understanding IGF-1 (Insulin-Like Growth Factor) in Simple Terms; Dr. Berg talks about IGF-1 Insulin-Like Growth Factor. This is an extension of Growth Hormone. IGF-1 is made by the liver and triggered by GH (Growth Hormone). It does help in the release of fat. It is a fat burning hormone, it helps in releasing fuel when you are not eating. It works when insulin is low and will be decreased when there is high cortisol (stress), high insulin (sugar) and high estrogen.

[3] #1 Diet Tip for Hypoglycemia (Low Blood Sugar)

[4] The #1 Food that Fixes Hypoglycemia

[5] The IGF-1 Trade-Off: Performance vs. Longevity: “…There is a tradeoff when it comes to growth hormone and IGF-1. Growth hormone and IGF-1 enhance muscle and cognitive performance but this comes at a cost: longevity. Reduced growth hormone and IGF-1 increase lifespan by increasing the expression of genes involved in stress resistance but at an expensive cost when it comes to muscles and brain. Learn all about the trade-off and ways to circumvent it. …” …More


There seems to be a fight between the two hormones, one being catabolic; the other being anabolic, what you eat determines how that battle is won. Interestingly, the study mentioned in the video showed no response in those who were low carb but very high in those on the SAD. It was also affirmed that eating fat doesn’t induce an insulin response, hence if when in ketosis excess protein is converted to fat then stored in fat cells suggests that eating excess protein shouldn’t have a a deleterious effect on BS. But it seems that there was one caveat that suggested if just starting out on a low carb diet it will take time for this process to be functioning, which makes sense too. I haven’t done enough reading to understand all of this but it’s very disheartening that those who are the most revered in the study of the human body can’t answer some basic questions in laymen terms. Perhaps I am being too harsh, they can’t help it if what they have learned is based on the bodies reaction on a SAD diet, it will be a long time before any of this changes and perhaps not in our lifetime, I probably shouldn’t even be commenting on this stuff myself, I feel quite the fool doing so. Thank you for your very detailed response I have added much to me list of reading.

(Allie) #55

I’m told it’s demand driven and nothing to worry about, but when I eat lots of protein my ketone levels plummet. Although I don’t stress about it as I’ve got enough metabolic flexibility to dip in out of ketosis without difficulty.

(Doug) #56

Crickette, you’re not dumb and it’s an interesting question. I think the bottom line is that “too much protein turns to sugar” is a myth. That does not mean that the body won’t burn protein for energy under some conditions.

Many people handle a relatively high amount of protein in their diet well. Here’s a study where 3 groups were fed almost 1000 calories (~40% of their normal caloric intake to maintain a set weight) above their normal caloric intake. The groups had protein intakes of 5%, 15%, and 25%. The amount of fat gained in 8 weeks was very similar among all groups. The two higher % protein groups had higher weight gain overall, the difference being a gain in lean mass, while the lowest protein group lost a little bit of lean mass.

Higher protein intake did not make for any more fat gain; it just made for increased resting energy expenditure and a lean mass gain versus a small loss. These were not people eating ketogenically.

“Excess” protein really does not describe the conditions where the body will use it as fuel, even though that may sound counter-intuitive. The body can store a little bit of carbohydrates as glycogen, and it can of course store huge amounts of fat, but it doesn’t really store protein at all. Excess protein gets broken down and excreted as urea (placing increased load on the kidneys).

Where protein gets used for energy is when the body is in an energy crisis (real starvation) and it doesn’t have carbohydrates to burn, and it can’t burn enough fat - doesn’t have enough, isn’t adapted to it, or due to other causes like high insulin levels.


Thank you for the article and the encouragement, I definitely have a better understanding of what isn’t known. lol.


Too much protein is better than too little. Dr Ted Naiman MD


Amy Berger is also worth reading


Do you know if it also unhealthy when the body use protein as fuel (when in calorie deficit/starvation)? I have read that too much protein can make people feel less energetic. What is the caus eof this? The work of the kidneys, the conversion of protein to fuel or the starvation itself? Or all three?

(Doug) #61

Davida, I don’t really think it’s “unhealthy” for the body to be burning protein when it thinks it has to. If one is really ‘starving’ and to the point where one is consuming one’s own muscle or other desired lean mass, then that’s a bad situation for most of us but I’d usually trust the body to do what it has to do, there.

On feeling less energetic, I really don’t know. I’ve never felt tired, personally, even when eating ridiculous amounts of protein. From what I’ve seen, it’s not that frequent that high protein makes people less energetic.

If one is fasting or eating well under their daily caloric expenditure, then if they’re not fat-adapted or are very lean with little fat to use, that would explain tiredness. There is the “thermic effect” of protein - as high as 35% of the energy in it is used just in the digestion of it. Makes people feel hotter, often, but I don’t think frequent tiredness is a thing there either.

Kidney problems might affect things when the kidneys are relatively burdened with getting rid of a lot of the byproducts of protein digestion and excretion. Just theorizing here - if the body is having trouble getting rid of the ammonia produced from protein breakdown and the urea (that the liver makes from ammonia (the ‘ornithine cycle’) because it’s less toxic than ammonia) then yeah, one might feel bad.

(Mark Rhodes) #62

I loved the comment the way it was…any changes will force me to rescind my <3

(Nicole Sawchuk) #63

in my recent n = 1 I have focused a lot on my protein consumption and have increased it significantly. I am now slim and while I still have some fat on me, I felt I was at a point now where I was losing lean body mass. I was worried my BG would suffer but honestly I have never seen them so low or steady in a long time! Yes my ketone levels have dropped but I am still in ketosis and I stopped worrying about my ketone levels. After 3 years of this, I think I am just efficient at using ketones appropriately and I only use what I need. Like you said, I now have enough metabolic flexibility that even when I dip out of ketosis, it takes no time for me to be back into it.

I’m with Amy Berger, I want to lose fat not LBM. I am really focusing on rebuilding that.

On a side note, no matter how much fat I ate, I always felt hungry. It just did not satiate me. With my increased protein (1.8g/kg LBM), I finally feel satiated (don’t get me wrong, I eat fatty cuts of meat and still see the value of fat). While I have seen my weight go up, I actually see my body getting leaner where as when I was consuming lots of fat, I just didn’t see these type of results.

(Tovan Nhsh) #64

A lot of what I’ve read says it’s demand driven, I.E. your body will produce what it needs regardless. Personally I do not know for a fact either way but my experience has been extra protein is fine (dependent upon what “extra” means).

For the first three years of keto I worked to keep my protein towards the lower end of the scale. On average between 65-80 g/per day. During that time if I had a protein heavy day (90+) I noticed my BG was elevated which seemed to confirm the idea that too much protein was not a good idea. The downside being I lost some lean body mass & developed an almost gaunt appearance.

However, over the past month or two I’ve dropped all plant matter from my diet & gone carnivore which has led to much higher daily protein intake. Surprisingly, after the first week or so, not only was my baseline BG not elevated it was actually a few points lower than normal. Added to that my ketone levels have remained consistent throughout. As an additional benefit, I’m losing the gaunt look without gaining fat.

Obviously everyone is different but in my case extra protein was not a problem.

(Bob M) #65

I bought a continuous glucose monitor specifically to test whether I would get higher glucose levels after eating high protein meals. I ate upwards of 150 grams of protein in a meal and could find no evidence either of an increase or decrease in blood sugar. For instance, I could eat a pound of 80/20 ground meat (120 grams of protein) and one can of anchovies with olive oil, and could not tell at all when I ate. I would eat shrimp + mussels + fish (eg, sardines), and get maybe a tiny initial rise, which I attributed to some carbs in the shrimp and mussels.

After several months of testing, I gave up. I could not find a delayed blood sugar rise or any blood sugar rise.

Note I think this is highly variable. Jimmy Moore experienced hypoglycemia (low blood sugar) from eating high protein meals.

Another interesting question is whether higher protein affected my ketone levels. I initially thought so, as I would fast 36 hours, workout, then eat a high protein meal. Testing ketones after eating showed what I thought were lower ketones relative to a morning/before workout ketone level. However, with more testing, including testing before and after the workout, I realize that my ketones plummet (and my blood sugar rises) when I work out after fasting 36 hours. That’s independent of eating.

So, it’s unclear. It’s also muddied by the fact that if I eat higher fat, that seems to increase my ketones. Thus, if I eat a high protein, low fat meal after exercising, but then have a higher fat dinner (typical for me), any lowering effect of protein will be counteracted by the higher fat dinner. It’s further muddied by the fact that I test ketones at most 4 times a day, typically much less, which is not a lot.

Also, note that Jimmy Moore and Dr. Limansky tried high protein, lower fat, lower calorie for a week, their ketone levels went UP.

After testing higher protein, lower fat for months, I’ve moved to eating lower fat, higher protein, typically. I’ll still have some higher fat keto meals, but most of meat is lower in fat. (Though I don’t throw away chicken skin, eat only the breast meat, etc., as I did in my low fat days – I eat the meat I have, and all of it; I’ve just transitioned to eating ham instead of salami, for instance.)

(CharleyD) #66

Don’t forget, when you eat meat that the complete protein is broken down into component amino acids.

The following links list which amino acids can possibly be turned into glucose or ketones by the liver during metabolism. It doesn’t go into what are the precise circumstances for those conversions though. It’s likely to be either highly individualized, or actually, it may happen all the time just at low levels.

(Bob M) #67

Everyone should listen to the KetoHacking MD podcast, with Jimmy Moore and John Limansky, for these issues. They went on high protein/low fat (3:1 by grams) and lower calorie for one week. Jimmy Moore had hypoglycemia, both had their ketones level go UP not down. Then they tried a diet of 90% fat for one week, and Jimmy Moore had ketone levels go DOWN, not up, and had terrible hypoglycemia, worse than on high protein.

They also interviewed many other people who tried the higher protein, 3:1 diet. Some liked, some did not.

For me, higher fat intake typically means higher ketone levels. It’s really the only way I can get my BOHB greater than 1.0, or fasting multiple days. Otherwise, I’m always below 1.0.

I have found higher protein is possibly better, but it’s a complex issue even for me.