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Dietary Carbohydrates Impair Healthspan and Promote Mortality (cell.com)
158 points by hunterjrj 40 days ago | hide | past | web | 114 comments | favorite



Note that this is probably not what you are thinking (low-carb, very-low carb or even keto diets are good for your healthspan).

The lowest quintile in this study were consuming 46,4% of kcal from carbs (that's about 230 gram of carbs for a 2000 kcal total intake). Not even close to low carb by today's standard in the health blogosphere.

The authors make this explicit in the discussion section:

>>> However, the absence of association between low carbohydrate intake (eg, <50% of energy) and health outcomes does not provide support for very low carbohydrate diets. Importantly, a certain amount of carbohydrate is necessary to meet short-term energy demands during physical activity and so moderate intakes (eg, 50–55% of energy) are likely to be more appropriate than either very high or very low carbohydrate intakes.


Anecdatum, but I play competitive basketball on a very low carbohydrate diet (<20g/day), and feel just fine, so necessary seems necessarily false.

The missing concept (in the brief quote in your comment) might be "fat adaptation", which takes (in my experience) 2-4 weeks (details: http://www.artandscienceoflowcarb.com/the-art-and-science-of... )

One certainly can fuel activity with carbohydrates, but a fat-adapted person should have no trouble with physical activity on a (very) low carbohydrate diet. Interestingly, a fat-adapted athlete can still use carbohydrates for supplemental fuel before, during, or immediately following extreme exertion (no adaptation is required for short-term use of carbohydrates).


The book The Lore of Running covers this as well. For normal day to day things this is fine. However, it is extremely understudied with minimal evidence it works for everyone.

https://www.google.com/amp/s/www.runnersworld.com/newswire/d...

It is still unclear, and dubious to claim, that you can operate at 80+ percent VO2 max on hard work outs. Maybe for short workouts or workouts with bursts of activity e.g. basketball.

You can also undo fat adaptation pretty easily. The answer is it depends, but there is little evidence it has any large negative effects. Questions on peak performance vs "feeling fine" will be interesting to see in studies.


I wonder if many people have tested VO2 max like this. Anecdotally, I know that I have a very difficult time getting my heart rate over 150 if I don't consume carbs, while I can easily get it 160+ if I've consumed carbs. I don't notice a qualitative difference, except during HIIT exercise, but I believe there is a subtle one based on my heart rate.


I have. I found a cool place that did lactate threshold (via constant blood sampling) Dexa fat scans and VO2 max).

The thing is you can use RPE. We basically mean sustained 4/5 effort (rating of perceived on a scale of 1-5). It's a good enough proxy. VO2 max is also tricky because some people have higher or lower VO2 max but go faster or slower. Higher max != Faster times.

I think the sweet spot for very low carb diets is ultra marathon where you keep your HR around 130-140 anyway, wherein you would use fat anyway. Simple fact is you can't max your power output in an aerobic capacity without carbs. This is not disputed. What we want to know is where the cut off point is in terms of percentage of VO2 max.

Edit: just adding, Noakes talks about ultra performance in his book. It covers everything I saw in that book. He dives deep into the body systems and energy production of the body to suss out the science involved.


Great comment, I'm curious about all this too. I'd be interested in more precise data than my own vague n = 1 impressions!

I actually spent a fair bit of time delivering VO2 max tests to athletes (in a previous life as an exercise physiology lab volunteer).

This comment has me wondering if I still know any active researchers in this area, looking for ideas...


I have tried it too. I did not PR in the 5k I tried it for. I think on long runs I never noticed, but 50 minute sessions with 5k pace intervals never felt the same zip as I did on carbs. I was consistent with it for 3-4 months so I am sure I was fat adapted. I noticed my water weight was less unstable (my weight didn't fluctuate as much day to day.) I still like periods of low carb, but I found it onnerous to stay I'm that 20g or less range always. Especially with kids and a wife not on the same diet. So I am optimistically on board the low carb diet scheme, it was fine for me. I cautiously think fine for almost everyone. But... :)


OP here. Fully agree. I do 2-3 keto cycles (5 weeks) per year. Not against keto diet.

But note that the context of this study is healthspan and mortality, not athletic performance, weight loss, etc.

It was just warning that this study does not warrant that keto diet is good for your health in the long term. The title is a bit misleading.


Fair to say the study results themselves (as opposed to the authors' assertion quoted in the gp) don't really pertain to the health effect of low carb/keto, at all (ie null rather than evidence for or against)?


> Importantly, a certain amount of carbohydrate is necessary to meet short-term energy demands during physical activity [...]

Why would they make such a claim? Anyone who has done keto and worked out has probably had the experience of doing quite a lot of physical activity while having had no carbohydrate intake at all for half a day before, or more.


At most, your brain can run with 75% ketones/25% glucose. Other organs (kidneys, red blood cells, cornea) need about 15-25 grams/carb per day. If you do not get glucose from diet, your body will build it (gluconeogenesis).

Must see if you want to understand/practice keto right:

https://www.youtube.com/user/chrismasterjohn/videos


I started a keto diet 2 weeks ago.

As far as my research into keto goes eating too much carbs kicks you out of ketosis (duh!) and eating too much protein triggers gluconeogenesis which also kicks you out of ketosis. Which is a shame because I'd be happy to eat fatty steak and fatty pork all the time!

Keto guidelines generally say 30g carbs per day and that's what I'm going to stick to (net carbs; I want to eat avocados!). So typical keto diet should work fine with what you say about carb requirement.

I don't have any particular desire to go all the way to 0 (or some really low number) and if I have some carb budget left I'm happy to get a latte. Starbucks says grande almond latte has 9g carbs (5g sugars). Perfect to tidy it up to just below 30g/day.


What was your motivation for starting the keto diet?


I've been weightlifting for a while and got fitter and stronger but the progress has been slow so I decided to change things up. I read about keto and the more I read the more awesome it seemed.

Since I switched to keto I have an amazing mental clarity. Literally from the moment I open my eyes in the morning I feel lucid (before I'd take me maybe 30 min and maybe a coffee to "wake up"). And I feel lucid all the way until I fall asleep (I don't get tired before falling asleep. Just go to bed, sleep). Nice and steady energy throughout the day.

Also, I feel noticeably better overall. My max strength suffered a little bit (keto can take 1-3 months to adjust) but I'm more energetic throughout the day, mind and body.


Not sure what this other guy will say, but for the vast majority of people it is for major weight loss, not necessarily lifestyle or belief that it is a "superior" health approach. This is my experience from Reddit's keto and loseit communities anyway.


> If you do not get glucose from diet, your body will build it (gluconeogenesis).

That is also my knowledge. Therefore, there seems no need for any intake of carbohydrates; So the claim about "needing carbohydrates" is not warranted (about intake, anyway)


Half a day of carb restriction wouldn't meaningfully deplete glycogen stores.


I’ve been <20g of carbs per day since February 2016. My athletic performance was impaired for the first 6-8 weeks, but has since increased dramatically.

At low circulating insulin levels, most cells in your body can efficiently metabolize fatty acids. For the minority of cells that cannot, your liver converts protein into sugar by a process known as gluconeogenesis.

It’s very possible to be a performance athlete and eat very low carb.


80m of exercise is enough to deplete muscle glycogen to as-near-zero as makes no difference.

In a sessile starvation state glycogen stops being a meaningful energy source after 2 days, with the majority of it depleted in approximately 8-12 hrs (it's non-linear).

Depending on one's baseline physical activity and what they mean by "half a day," sure, glycogen stores can be reasonably depleted.

That said, glucogenic amino acids can replenish glucose stores, which can ultimately become glycogen. Glycogen remains low only in the context of low-carb and low-total calories, so what glycogen is replenished is soon exhausted.


...even if you'd already been doing keto on an ongoing basis?


„no carbohydrate intake at all for half a day before“ no way your body was in ketosis.


"Doing keto" implies less than 20g/day on an ongoing basis, at least as I understand it. On top of that, one might have eaten early in the previous day, eaten no breakfast, and be working out about lunch time, which would provide the "at least half a day without carbs of any kind".

It may be that you disagree, but I get the feeling that you ignored the "doing keto" part of my setup, and instead thought that the person in question was eating cake 12.5 hours before the workout. :)


the specific number varies between different people. i'd say <20g is enough to get everybody into ketosis. <50g is enough for some.


It takes about a week of < 20g/carbs a day for the body to go into ketosis. This is born out by buying keto strips and testing your urine.


I can achieve 'dark purple' on strips in two to three days without drastic dietary or exercise extremes. This is one of my biggest sticking points with articles that make generalizations about body functions. There are always outlying examples and exceptions.


You probably already know this, but in case other readers don't, the depth of color on keto sticks is NOT a measure of "how deeply in ketosis" you are.

The depth of color indicates how concentrated ketones are in your urine, which is impacted by (1) the amount of ketones your body is producing, and, very importantly, (2) your hydration level (i.e. how diluted your urine is).

For newbies, if the stick is pink AT ALL, congrats, you're in ketosis. Don't make the depth of color a big goal.


this is not true for all people and urine tests are not considered reliable. I can get into ketosis in a single day of fasting


A little known fact is that you can induce ketosis while eating carbs. The biochemistry here is clear: You get into ketosis when you oversupply acetyl groups to the TCA cycle. Adding MCT (Medium Chain triglycerides) to your diet will do this.


I think this needs a little more explanation. Can you provide that?



It takes 3 days for me to hit ketosis at that carb level.


>during physical activity

As someone who has been on a low-carb diet for 3 years, on and off, I definitely don't notice any difference in performance, mood or productivity while on a low-carb diet. Too many people (esp. those in a desk job) over estimate their physical activity levels and think they need more carbs.

Sure, if you're an athlete, all this doesn't apply to you. But, for the vast majority (who in the present day) lead highly sedentary lifestyles, it's about time we encourage them to get off carbs as much as possible.


I think the assumption there is very-low carb (as a macro-nutrient, not "healthy" v "unhealthy") can be better if _lower_ carb demonstrates improved outcomes... ?


That is about what I have been eating naturally (~150-250g carbs daily, pretty much from oats, potatoes, sweet potatoes, dairy, and 1-2 servings of fruit per day).


There’s no such thing as necessary carbohydrates. The body is capable of producing all the glucose it needs.


True, but think about non-necessary vs beneficial vs optimal.

"Gluconeogenesis is extremely expensive" [1]

[1] https://www.youtube.com/watch?v=Og8PTdjVAWE


The key to cheap and non-harmful GNG is to have copious amounts of fats circulating, at a keto-typical low weight that means copious intakes of fats too. GNG ideally shouldn't/wouldn't happen from proteins (unless intake is very high) but from other metabolic byproducts and the glycerol backbones of triglycerides. Then this process typically accompanies ketosis in which ketones (endogenously produced-from-fat-burning types-of-carbohydrate but not from GNG) power most (not all) glucose-but-not-fat-burning-capable cells. Fat-adapted where possible, ketone-adapted elsewhere, and lots of byproducts that ordinarily would be "useless and to be excreted" (not just glycerol but also lactate, pyruvate etc) can now feed into (non-protein) GNG without the complications and expenses and downsides of protein-to-glucose GNG.


This study is highly flawed:

https://www.hsph.harvard.edu/nutritionsource/2017/09/08/pure...

Be careful making any changes to your diet based on these "findings". The healthiest populations on the planet eat plenty of carbs, but not refined sugars.


Even without the data quality issues, there are obvious uncontrolled confounding factors. I don't understand how a real scientist can title this study "Dietary Carbohydrates Impair . . ." when the finding is actually "Dietary Carbohydrates Are Associated With Impaired . . ." Clear evidence that statistical training (or perhaps just incentives) for scientists remains insufficient.

What's really surprising is how many people on here are like, "of course, ketogenic diets!" Where is all the skepticism that is so vividly on display when discussing the latest Google or Facebook product announcement?


Because they explain the causal link. See the paragraph beginning with, "Most dietary carbohydrates relevant for human nutrition contain the monosaccharide D-glucose".


Countless studies show that consuming refined sugars alone has very different effects on the body than consuming complex carbohydrates along with the fiber found in natural foods. This is like saying that all protein contains glutamate so there's no difference between eating a steak or a tablespoon full of refined MSG.


I think their claim is that most carbs are mostly made out of D-glucose. And that excessive amounts of it cause your insulin based signalling cascade to go wrong.

I'm sure that encapsulating your carbs in a nice hard-to-unwrap cellulose structure slows the release of this D-glucose stuff and gives your body's control loop more chance to cope. But at this point we're arguing about the details of the causal link.


I always wonder, when nutrition studies are usually so poorly designed and controlled, why people don't just look at the blue zone diets for nutrition guidance.


Had not heard of "Blue zone"s before [1]. (EDIT: Added [2])

[1]: http://www.npr.org/sections/thesalt/2015/04/11/398325030/eat...

[2]: http://bluezones.com/recipes/


Yep. We have multiple examples of multigenerational communities that regularly live to 100+. Poorly done studies like this one only serve to obscure the truth about what we should be eating for longevity.


if you live on a plant then you don't have much of a choice anyway.


I'm not surprised to see this at the top of HN considering how many people seem to be fans of the Keto Diet. I am very excited for people who find something that works for them, but I would be very wary of a study like this if you are looking for confirmation for multiple reasons:

1. The study "did not analyze which specific source of carbohydrates (e.g., sugar/refined carbs versus whole-grain products) may contribute to the detrimental effects of carbs observed, especially since income and wealth do impact the quality of dietary choices significantly."

This is HUGE. Any study or person that attempts to label an entire macronutrient as "bad" or "evil" is not helping anyone understand the whole picture. The most nutritious foods in the world are carbs. Many of the least nutritious foods are also carbs. Not distinguishing the two gets us nowhere.

2. With this study and most high fat/keto diet studies as well, the timeline is not long enough to tell us about true "lifespan" impact. This one is over 7.4 years. I know it's more difficult to do 10, 20, 30 year studies, but until something can be correlated over those timespans, I would not bet everything on that diet for longevity. There are a handful of generational studies, and almost all have shown that "high carb" or more specifically "plant based" ARE good for longevity. Not saying high fat aren't good for longevity as well, but we have yet to really see examples yet.

3. As many who have tried Keto specifically will tell you (as some have mentioned in the comments), it is very difficult to maintain a ketogenic state. You have to be very disciplined, and this is made harder when you are a social person. This is a big problem when talking about diet and longevity. If it's not fairly easy to maintain, then it's not a feasible diet for longevity where the average person is concerned.

4. As someone else mentioned, the percentage of carbs that the studies participants were eating were not even close to the level required for a Keto Diet


I've read a lot of, often conflicting, dietry guidance. I have realised one very important thing: humans will very easily accept that something they enjoy is bad for them (see fat, sex etc.) So listening to what people say is bad for them is stupid.

Instead I have taken a simpler approach: I observe the lifestyles of people who are healthy and live a long time. I have observed that eating simply "good, old-fashioned" home cooked food is important. My grandmother lived into her 90s. Ate fat and carbs. Julia Child lived into her 90s. Ate fat and carbs. Edna Lewis lived into her 90s. Ate fat and carbs. I could go on. Just do what they did and you'll have as good a chance as any.


The problem is that simple home cooked food can't be commercialized. So all advice that gets published will be for something where you can buy a product.

Same for exercise. We already know how to exercise but there are always people who want to make money by repackaging it.


I don't know why, but I always felt that there was a market for a no-bullshit movement, but I fear that the appeal of more money perverts the movement, and then it just becomes like every other commodity. I think most things probably start as well-intentioned, and whether it's money or power, something happens along the way and subverts the whole thing.


I think those things can be commercialized but they have not been to the extent that Keto diets have.


I fear you may be correct.


Selection bias is something worth avoiding in understanding health studies. It’s quite likely that you know about these folks because they had the right genetics to be healthy outliers, and by extension, famous. It’s no different than saying I know x people who didn’t die of lung cancer due to smoking, which doesn’t change the implication that y% of smokers will always get lung cancer, we just haven’t figured out what fully constitutes your risk ( genetics etc)


I have to agree. "Just do what they did and you'll have as good a chance as any." is very dangerous advice for many reasons. Besides selection/survivorship bias, you have NO idea what the true lifestyle of celebrities is outside of what you are shown.

People have survived smoking a cigar a day for decades, but that's a terrible reason to justify the habit, especially when information says otherwise in the other 99% of cases.


This is why it is better to look at long-term national data rather than selective studies (such as the one noted in the title) which fail to control for obvious discrepancies in their data which would contradict the click-bait headline. The populations that have the longest average lifespans seem to have a few things in common and carbs are one of those common factors.


Well my grandmother wasn't famous. I'm not limiting my experience to famous people, I'm just including them.


That's survivor bias. You're missing all the people that died eating fat and carbs at a statistically higher rate than those who did not.


I'm sorry - this is naive advice. Generalized, this would mean that we shouldn't innovate or develop anything new at all (if what's worked previously is the ONLY way it should work).

Especially, with something related to diet and nutrition, there is an ever evolving need to alter our habits with the way our lifestyles changed. The kind of life your grandmother led is vastly different than the way you do now.

Similarly, carbs were great when as a culture we embraced agriculture, started working the fields and were able to secure food supplies for emergencies and the next generation. Now, farm productivities have shot up, fewer of us are working directly on growing food and there's abundance of food choices all around. We no longer need the easy glucose that we needed earlier. So, it is important that we change our dietary choices if we want to lead healthier lives.


What do you suggest that I do then? Read each contradicting study and alter my habits? Or just do whatever I want and wait until there is some real, true, conclusive evidence that something other than what your grandma ate is better for you? I'll be dead by then. I eat every day. I need to choose what to eat now.


I’ve been living a ketogenic lifestyle for a few years now. I go in and out once and a while but seeing the “fat is bad” theory thrown out the window with research like this makes it easier to remain committed.

The trouble comes with the way society has been conditioned to have carbs with every meal. Like 90% of the food my peer group eats are surrounded in carbs. Even for a company-wide lunch in the office: the go-to is usually a couple dozen pizzas.

Once you’ve lived low carb for a long time you look at people in line at a coffee house grabbing a bagel and a milkshake and just feel bad for the crash they will have later.

I’m happy to see Keto becoming more and more socially known. Accessiblity around low carb options is getting better and better. My favorite will always be a protein style burger from In-N-Out though.


You hit the nail on the head for exactly why I couldn't stick with a ketogenic diet. It became too much of a burden on the people I was with to feed just me because everything they wanted was stuff like tacos, pizza, rice dishes, fried dishes, etc. I have an unresearched (by me) theory that the reason we have so many carb heavy diets is due to the fact that carbs are such cheap calories. They were good for surviving when we were poor but now we should move past them


Americans have a tendency to go to extremes. The normal American diet is way too high in carbs, and so when we try to do something about that we go way farther in the other direction than we have to. We aim for very low carbs, and that ends up being a pain, and we revert back to our default ridiculously high carb diet.

It doesn't have to be so binary.

Try aiming for a modest level of carbs. I aimed for 40% of calories from carbs, and ended up around 30-35%. That was a significant reduction, but nowhere near what most would consider low carb.

At that level of carbs you can have tacos, and pizza, and those other things. You might have to tweak some of them (add more meat to your pizza, for example) or pair them with other dishes to balance them out, but tweaking is a lot easier than foregoing them.

Are the very low carb diets better? It's unclear but even if they are, a merely OK diet that you can stick to long term is better than a great diet that you cannot stick to.

Will this work for you? Maybe not--one of the most important things researchers are learning is that there is no one size fits all in diet. It worked well for me [1], and it is pretty easy to try, so why not give it a shot?

I picked 40% as a first goal because it is easy to compute from the nutrition label. Take calories, divide by 10, and change the unit from "calories" to "grams", and that is how many grams of carbs that food can have and still meet the 40% goal.

To see if the whole meal meets the goal, just do the check for each item, and keep track of the total of the differences between cal/10 and g carbs for each item.

For example, suppose you are considered a Wendy's double with cheese, and large fries. The burger is 810 calories, 36g of carbs. 81 > 36, so it easily meets the 40% goal. The fries are 530 calories, 64g of carbs. 53 < 64, so they are over the goal. But how about the meal as a whole? You could add the calories, and add the carbs, and compare, but better is to look at how many carbs you would need to add or remove to each item without changing the calories to make it 40%.

For the burger, you could add 45g of carbs and meet the goal. For the fries, you would have to remove 11g of carbs, or add -11g carbs. 45g + -11g = 34g of carbs. Your proposed meal is OK.

Now suppose that afternoon you have the chance to have a chocolate chip cookie. 200 calories, 30g carbs. It's over 40% (20 < 30) by 10g. But you were ahead 34g after your earlier meal, so you can have the cookie and still be OK for that day. Having the cookie brings you to 24g ahead for the day.

What I did was try to make sure that the first meal of the day had lots of protein and fat, so that I would be ahead by quite a bit. I'd then keep track mentally of how far ahead I was during the day, and would try to avoid letting myself get behind.

In theory there is nothing wrong with letting yourself get behind at breakfast or lunch, and making it up at dinner. In practice, though, that means that if anything happens that disrupts your dinner plans you could end up behind for the day. If you start ahead disruptions are less likely to blow the whole day.

[1] Result: 140 pounds lost over 18 months, and stable weight since then (six months). (Also a drop in blood sugar, from an A1C of 8.1 on multiple diabetes meds to 4.8 on no meds. I've been under 5 for the last six months, and my doctor removed the diagnoses of diabetes from my chart).


agreed. I wish ketogenic meal kits and keto-friendly restaurant ratings / reviews / guides / accreditation were more prominent.


Check out the /r/keto sidebar on Reddit. I keep various PDFs in Dropbox of keto options at various fast food establishments. You can always get taco bowls with no tortillas, McDonald's without the buns, a burger without the buns at a burger joint, etc.

For emergencies, I keep a few shaker bottles in my car with protein power already added. I just add water if we go somewhere with no keto options.


Yep. It’s all thanks to the agricultural boom. Grain is everywhere and it is CHEAP.


And subsidized!


rice and tortillas are carbs.


But this research says nothing about such a strict and artificial diet over a long period of time. I wonder, do you know of any people who have eaten keto all their life and lived to an old age?


A few years does not prove a lifetime. If a million people ate your diet and lived X% longer than a similar set of people who didn't it might prove a useful stat. You might wind up dying of something not obvious today at 70 due to your diet, or not. No easy way to know. That's the problem of dietary knowledge.


totally agree. when there are no carbs around me - i have zero problems sticking to keto. whenever there's a party and some snacks - i'm in a danger zone unless i brought my own snacks in which case i'm a weirdo.


Don't bother about it. In the eyes of the others, everybody who is in a keto diet is already a weirdo :-)


Reading through all the comments and this one stood out. I am currently a 'reluctant vegetarian' for health reasons of course (bad choices were made during my younger years and now I am so paying for it). However. In-N-Out would be allowed were I near one. I like to eat grass (grass like veggies). Cows eat grass. I will eat the cow that ate the grass at In-N-Out burger. /shrug. Sounds legit to me. - I'd also have a 'healthy shake' there as well. I remember their adverts that mimic'd/mocked the shake diets and it still makes me chuckle.


what crash? are all these people you see in the coffee shop diabetic?


I've been on keto (on and off) about 50% of the time in the past 3 years.

The worst part is not being able to eat/drink at social events, and dehydration.

The best part is never feeling hungry, stable energy levels throughout the day, and not needing to sleep as much.

I also tend to binge a lot when off keto...


Oddly enough, every time I practice Keto, I am almost the exact opposite; always hungry, cruddy energy but I sleep like a rock. On low(ish) fat and high carb; easily satiated, decent energy, sleep like a baby (awake a lot but no screaming or poop). With the above explained, I have not tried A Balanced Diet - perhaps to get the positives of both modes and mitigate or lessen the negatives. Honestly this is the first time, while I am typing this, that I've come up with that angle for myself.


>I also tend to binge a lot when off keto...

Probably on carbohydrates because that is why everyone here is "on and off".


You can drink at events. Stick to soda water and vodka or diet coke and vodka, etc.


Not needing to sleep as much?


I tend to wake up earlier when on keto (~1 hour).


Fat is bad for some people, though. How satiated someone is by carbs or protein tends to be pretty consistent, but fat is more variable between individuals. Some people are just predisposed to overeating fats.


Yep, it's surprising how hard it is to avoid. Compound that with sugar being in almost everything and it ends up being remarkably hard to find options that won't cause your blood sugar level to spike.


Do you have any recommended reading on your diet, and the potential problems of a modern milkshake-abundant one? I could just Google it but it's hard to cut through the noise/misinformation when researching diet stuff for the first time.

Mainly asking because my diet yesterday was a six pack of Kirin Ichiban beer, a double cheeseburger, and a large P. Terry's chocolate shake, and I felt fine and still had a very productive day. I want to know why I'm able to tolerate stuff like that, and how/if that armor might start falling off as I get older.


Not GP, but I've also followed a ketogenic diet for a couple of years now. When I first started I learned a lot from Dr. Peter Attia and the videos he has on YouTube.

One example[1] goes through him talking about the self-experimentation he's done with the diet and the variations of it. From memory, it was pretty informative (albeit general) on the chemistry/biology surrounding it.

[1] https://www.youtube.com/watch?v=NqwvcrA7oe8


>The trouble comes with the way society has been conditioned to have carbs with every meal.

I am pretty sure that isn't conditioning. Eating a burger with no chips is just plain wrong, and the same the other way around as well. When I am eating rice and meat together, if I eat just meat, it doesn't taste good. It is so specific, that there is a specific amount of rice that has to go with the meat. Everyone knows this. That can't possibly be conditioning. People complain of "too little rice", "too much meat" etc. No one could have been conditioned so specifically.


> Next, a number of studies have evaluated the effects of specific macronutrients on lifespan, initially in S. cerevisiae (Lin et al., 2002), subsequently in C. elegans (Schulz et al., 2007 and follow-ups), and mice. Out of the latter, two studies in the previous issue of Cell Metabolism have studied this in mice starting at 12 months of age. In regards to the PURE study, most notably, the almost complete removal of carbohydrates (<1%) from the diet to generate a ketogenic diet extended lifespan compared to a high-carb diet. However, reconstituting only 10% of energy of the ketogenic diet by sugar abolished this effect (Roberts et al., 2017), suggesting that specifically sugar (rather than carbohydrates in general) has the most relevant effect on lifespan. Along this line, it is also interesting to note that when nutritive sugar content is kept constant, a different (and less extreme) high-carb diet exerts the best effects on murine lifespan. By contrast, a high-fat diet still containing the same amount of sugar, but no other carbs reduced lifespan slightly. Lastly, when combining high-fat and high-carb components from the two previous diets, the worst effect on lifespan was observed (Keipert et al., 2011). Moreover, lifespan extension in mice was also obtained when dietary protein was replaced by carbs, possibly independent of the total uptake in calories (Solon-Biet et al., 2014). Taken together, these studies suggest that dietary sugar may be one important, but not the only, nutritional factor in limiting healthspan in rodents, hence additional studies are definitely required to establish firm evidence in model organisms.

This section of the article does not correspond to the title. In fact it seemed all over the place, then goes on to conclude ‘maybe it’s refined sugars.’


Related; I saw on Hacker News awhile back a really great website that aggregates a lot of this health research and then gives summaries of, "What's the current known truth" based on all of the varying research. They then re-market that data as a service somehow. Anyone on here recall this by chance as I'm no longer able to locate it?



Yes, thank you! I've favorited it so I won't lose it again.



Does it bother anyone that this study is intentionally misleading by masking the fact that the carbohydrates tested were refined sugars?


as I mentioned in my comment, any study that lumps together all of one macronutrient into one group and then attempts to reach conclusions based on that grouping has very little understanding of nutrition.


I’ve found eating out socially on keto a big challenge (carbs still look delicious) until I found a hack: unreasonably large portions of salad, covered in salt. Salt is fucking delicious. Add olive oil too if you feel like it.


I drown everything in olive oil. Good, European protected designation of origin (PDO), protected geographical indication (PGI), and traditional specialities guaranteed (TSG) type olive oils. They're delicious. And you get full rather quickly. That feeling lasts. And I'm fairly certain the plant fat is not what's making us jiggly


Why so many labels in your oil? Isn't extra virgin sufficient?


Actually, no. A large majority of "olive oil" sold is either fake or adulterated. Those extra labels he mentions are to identify genuine and clean olive oil.


Are there any brands available on Amazon which meet this criteria?


Oil is an extremely concentrated form of energy and your body will most certainly store it as fat if you eat too much of it.


"Too much" is by definition more than what you ought to consume. On a keto diet, olive oil is an excellent source of fat. Used as salad dressing, it's highly unlikely to cross the "too much" threshold.


Satiation from fat varies per individual. Typically it does not satiate any more than carbs (calorie for calorie) and lead to easy over consumption.


> easy over consumption

I heard this for years and years, but it doesn't pass the sniff test for me.

Go try to eat a stick of butter. Drink some straight cream. Chew on the fat that comes with your beef roast. Sip sausage grease. Drink straight olive oil.

All of these things are hard to do. If I get past two or three hundred calories with any of them, I am workin for it.

I have this drink in the morning, 240 calories of butter and coconut oil in tea, and oh my goodness is that thing substantial. Finishing it is sometimes a bit of work.

But how easy is it to drink 300 calories of sugar and not notice it? Veeeeeeeeeery easy.

I think the idea that what makes food easy to overconsume is volume... I think this idea is so obviously wrong that I wonder if it was ever tested. It certainly doesn't seem subjectively true. Everyone knows rich food is hard to eat!


> Go try to eat a stick of butter. Drink some straight cream. Chew on the fat that comes with your beef roast. Sip sausage grease. Drink straight olive oil.

I haven't tried sausage grease (hard to get the temperature right?), but I have happily done all the others, and the only reason I don't today is because I don't want the calories.

Not everyone is the same.


Studies are better than biased self tests. Even self study where you try to apply perceived ratings and controlled calorie measuring is better than a sniff test. Try following the setup for some studies on fat vs. carb satiation and see what you come up with. In my experience on a sustained calorie deficit total calories matters most as long as it isn't a refined sugar causing glycemic spikes. I think fibrous carbs vs refined carbs does have an impact. Otherwise, probably much less.


And yet many of the longest-lived populations on earth have diets rich in carbohydrates, like the Okinawans.

I hate associational studies like this which don't distinguish between types of carbohydrates (sugar vs starch) or other factors, like whether they were eating whole meals of natural foods or snacking on potato chips 24/7.

But at least they've finally noticed they were completely wrong about saturated fat for 80 years.


tl;dr Refined sugar contributes to getting fat, and an early grave. No shit, Sherlock. They conveniently left out any reference to fiber, or the exact sources of said carbohydrates. Sources matter tremendously due to fiber content and levels of refinement.

Stick to fibrous veggies, beans, nuts, some fruit (berries are best), and you'll be just fine eating carbs.

I'm not contesting the fact that ketogenic diets work for people. But this study is kinda bullshit since it's basically alluding to the worst kind of high GI refined carbs


>>> (1)The conversion of D-glucose into metabolic intermediates, namely glycolysis, can be inhibited by compounds like (the highly efficient but rather toxic) 2-deoxy-D-glucose or (the less efficient but completely harmless) D-glucosamine (GlcN). The latter is widely used to treat arthrosis with the questionable claim of inducing cartilage regeneration. Both compounds have been shown to extend C. elegans lifespan (Schulz et al., 2007, Weimer et al., 2014), while only GlcN extends lifespan in rodents (Weimer et al., 2014). Notably, GlcN uptake has been also associated with reduced mortality in a large human cohort (Bell et al., 2012).

So does this mean the glucosamine chondroitin pills I take for my joints will help reduce glucose conversion and extend my lifespan?


As usual, correlation is incorrectly assumed to mean causality.

The summary text says there's causality. A few paragraphs into the study, the text interchangeably uses causality and correlation:

>> found that carbohydrate intake was associated with increased total mortality.

>> By contrast, any type of dietary fat reduced the likelihood of dying.


Can anyone provide a TLDR on what exactly the conclusion of this article is? My experience with a low-carb diet is quite similar to that of @whalesalad, and it remains much more effective than any other diet or a strict exercise regimen.


the TLDR is that this study tells us nothing about what diet is good for longevity.

See my comment: https://news.ycombinator.com/item?id=15465516


Dehghan et al. (2017)) found that carbohydrate intake was associated with increased total mortality. By contrast, any (saturated/monounsaturated/polyunsaturated) type of dietary fat reduced the likelihood of dying.


Take home message?

Eliminate sugar, increase saturated fat. This study provides little guidance on question “is total keto good or not”.


"Moreover, there was no link to cardiovascular events or related mortality, except for saturated fats, which were unexpectedly associated with a lower risk of stroke."

That's interesting.


Man I'm screwed. Don't drink, don't smoke, but totally addicted to carbs. Granola bars...mmmmmm


are you addicted to carbs, or are the critters living in your gut that get hangry when you starve them? more of a talking point because i dont have my head around it. my wife had me do a "die off" diet for several weeks of doing keto; i got super bloated, got a rash everywhere, and then all of a sudden felt skinny and good. ...then i binged and it was all normal again


I am my critters and my critters are me.




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