What is the current scientific consensus regarding these questions?

(Doing a Protein Sparing Modified Fast) #1

Now, it is some time I have not followed scientific papers on keto, and trying to read all the posts here is a daunting task.

Might, then, ask what is the current scientific consensus on:

  • Protein consumption, high or low: I remember Valter Longo and David Sinclair used to argue for low protein consumption, due to mTOR and AMPK issues (at least, from 30 years old to 65, more or less). But here many people are carnivores, so I guess their protein consumption is high (and of the type of protein the “longevists” argue is worse, i.e. red meat). Are there results about this issue?

  • Cycling keto: Mankind has spent most of its existence under the yearly cycles. So I guess our bodies are more or less used to be in keto for autumn and winter, and out of keto in spring and summer. But instead, most people are either on the keto side or on the non-keto side “always” (granted, there are people who do keto cycling, but this is a weekly cycle, not a yearly one). Are there results suggesting a yearly cycle is good/not-good?

(Old Baconian) #2
  1. Protein consumption is still being argued about. The understanding of mTOR is more nuanced these days, and people don’t seem as concerned about it as they once were, so now the debate is about how much is enough protein, and many people are putting the required intake quite high. Dr. Stephen Phinney expressed some concerns about what he considers high protein intake (over 1.5 g/kg of lean body mass) at Ketofest 2019, though I’m not sure exactly what those concerns are. On the other side of the debate is Prof. Benjamin Bikman, who is concerned about muscle retention later in life, and who feels that we need a high protein intake (2.0 g/kg LBM) all along in order to retain as much muscle as possible when we get older. I suspect that we don’t yet know enough to say what is best.

  2. If anything, I’d say the human race was mostly in ketosis except in autumn, when putting on weight for the winter. It doesn’t seem to be harmful over the long-term, especially since there are enough people who have been on a ketogenic diet for two years or longer for any long-term problems to have shown up. Furthermore, Dr. Phinney has been eating that way for a couple of decades, and I imagine that Dr. Westman has been at it even longer, and they are both in great shape. Vilhjalmur Stefansson, the Arctic explorer, ate a meat-only diet for most of his life, and he was in great shape when he died at age 82. My belief is that we have enough data to suggest that this is a safe way to eat over the long term. I also cannot see any mechanistic reason for fearing ketosis (apart from the risk of ketoacidosis to Type I diabetics, and that has nothing to do with what they eat), so I am willing to take my chances.


Paul’s response is far more elegant than mine. All I would add is:

  1. Protein should not be feared (unless you are obsessed by blood ketone numbers). It plays such an important role in the formation of bone and lean tissue. Further, it’s best sources (beef and organs) are incredibly rich in essential nutrients. Based on age and activity levels, I would go for the higher range (as per Ben Bikman for instance).

  2. Been debating this on another thread. Ultimately, unless you are willing to test yourself, e.g. using a CGM; fasting insulin; T3 levels; testosterone; maybe HSHBG, all you can do is size up the existing literature. As Paul mentioned, apart from Stefansson, there is no +12 month studies looking at long-term keto.

(Michael - When reality fails to meet expectations, the problem is not reality.) #4

For protein I fall mostly in the ‘more is better’ camp - with the caveat that one be self observant and adapt as needed. So I’m also in the ‘n=1’ camp - I’m eating for myself and no one else. Vice versa. I accept that individual variations are to be expected, within an overall range.

I’ve noted elsewhere - multiple times - my acceptance that ketosis is the normal, healthy metabolic state for humans. We evolved to gestate, grow and live in it. Prior to the Holocene, there is zero evidence that plant-based carbohydrate-rich foods were consumed by our paleolithic ancestors in anything beyond very minuscule amounts. I think the idea of seasonal fat/meat carb ‘cycling’ is wishful thinking. There is no evidence to support it.

Going back to Stefansson, he lived and studied with the Canadian Inuit (aka ‘eskimos’). He was not only an adventurer/explorer but also skilled observer. He studied the Inuit when they still ate their traditional diet consisting almost exclusively on fat and meat. He shared that diet with them all the years he spent in the arctic living among them. His Bellevue experiment was conducted on his part to try to get the medical/nutritional ‘establishment’ of the time to accept that a diet consisting exclusively of fat and meat was both nutritious and healthy.

(Old Baconian) #5

Please forgive a minor correction. The Virta Health study, conducted by Sarah Hallberg, is past the two-year mark. They showed a 60% reversal rate of Type II diabetes, as I recall, with no malign effects. And the recent study reported by Jeff Volek’s team was done on athletes who had been keto-adapted for two years or more. Now, these are certainly not randomised, controlled studies, but they do show the existence of some data.

And then there are the anecdotal data from people on these forums who have been eating a ketogenic diet for years with no discernible ill effects. Not that can be ascribed to their diet, any way. There are even people who have been eating a carbohydrate-free diet for ten years or longer, who are to all appearances perfectly healthy. Again, it’s not real data, but at a certain point a large number of anecdotes all pointing in the same direction start to mean something.

(Bob M) #6

I also think you could eat a relatively higher carb diet, say eating in season fruit, and still stay in ketosis, depending on you, your exercise level, time in ketosis, etc. While I generally don’t eat much fruit, we did go strawberry picking this spring, and I had some strawberries and yogurt. Still was in ketosis (though I only have a breath meter now).

(Old Baconian) #7

I’ve even heard it said that the doctors conducting the experiment on him and Anderson were quite disappointed that they didn’t develop scurvy. Although they should have known better, since the anti-scorbutic effect of fresh meat had already been known for at least a century, in 1928.

Also, Stefansson maintained his carnivore eating pattern until his death at age 82. It hardly appears that a carbohydrate-free diet can be all that dangerous, if his story is any indication. And how many years did Stanley Owsley eat a carbohydrate-free diet? And so forth.

For anyone interested, there are a couple of television interviews with Stefansson available on YouTube, as well as one with his widow.


Makes no difference what the “Science” says, because the people providing the science are biased in one direction or the other and their end goals dictate how their “studies” are done. “Science” says fat clogs your arteries and causes CVD… and it DOES… the way those studies were conducted! Somebody that didn’t have a bias and that did studies on people eat low carb or keto will show the opposite, and they’d also be correct. Just like everything context matters, and the context can completely change the outcome.

I believed the low protein thing for years, and lost a ton of muscle over it. All depends on your goals. I was completely unable to keep muscle on with lower protein and never deviating from standard keto, since cranking up protein I was able to put some muscle back on, and since switching to TKD/CKD I’ve been consistently regaining muscle and now have more muscle and lower bodyfat than I have in years, which was my goal.

I could care less what somebody did a couple hundred years ago, I don’t see any point in using the past as a way to decide while I’ll do if that’s not going to get me to my goals. My goals are progressing the way I want, I feel better, my labs are good, my inflammation is remaining low, my A1C is maintaining… I’m good! Don’t get me wrong, I’m all about the science, but I’m not going to override what gets me to my goals because somebody else says to.

(Doing a Protein Sparing Modified Fast) #9

Yes, I agree with all the comments.

In the end, there is a trade off: scientific studies on diet are almost always epidemiological (until we do not have devices in our bodies that track automatically what we eat), so the conclusions have to be taken with a pinch of salt.

Individual experiences, from individuals that know themselves well, are probably more valid.

But anyway, there is always the risk that something that goes well at the beginning, could have bad long term effects on longevity and healthspan.

I guess there is no right answer.