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Comment by strken | Hacker News Reader

I'm not convinced by some of the common beliefs about low-carb diets either. They seem to be good for weight loss[0] but bad for all-cause mortality[1]. If you're making dietary recommendations, it's hard to justify choosing a diet that makes the people who eat it skinnier and less diabetic but also kills some of them.

I'm also not convinced that "low-carb" in the literature means you can draw conclusions about ketogenic diets, especially ones that actually send you into ketosis. Some low-carb diets from that first meta-analysis had 35% carbs by energy!

My impression of the available evidence is that if you want to lose weight, calorie restriction and high-satiety foods matter more than macros.

[0] https://www.mdpi.com/2072-6643/12/12/3774/htm

[1] https://journals.plos.org/plosone/article?id=10.1371/journal...

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"Our meta-analysis supported long-term harm and no cardiovascular protection with low-carbohydrate diets. However, the observational studies were limited and moderately heterogeneous. Our findings underscore the imminent need for large-scale trials on the complex interactions between low-carbohydrate diets and long-term outcomes."

From your second link. Also not a surprise when many research about low carb diets is refined carbohydrates + unspecified oils.

"Low carb" studies are as interesting as "high carb" studies. High carb is a Mediterranean diet or is the Twinkie diet, just like keto can be meat and vegs or low carb pizza and processed meat. Lumping everything under one very generic name is not very good science. The whole dietary world is made of bad science and repeated by bad journalists.

The scientific jury is still out, as your very source stated, yet every HN thread the top voted comment is "low carb kills some people." Seriously?

I am still waiting for someone to show me a long-term study based on low carb meat, nuts, fruit and vegetables, unrefined oils and fats diet. Even an observational one. Oh wait, there's none!

I think low carb diets are easier to mess up without realizing.

one - you cant go no carb, so it requires very accurate moderation which is something people tend to be bad at

two - the cheaper sources of protein and fat, which you now must eat more of, are often high in omega-6 instead of omega-3, or have the wrong balance of saturated vs unsaturated fats, not enough amino acids, etc

three - if you go for Keto, getting hit by points 1 and 2 together can easily create a health risk. Too much protein kicks you out of ketosis as well. You might chronically knock yourself out of keto without realizing it and eat a bunch of foods that you really only get away with eating by being in

So even though a proper keto diet, for example, might be perfectly fine. Recommending a keto diet to the general public very well might kill some people who historically have a bad track record for moderating their food intake

> you cant go no carb

This is incorrect information. You can go, and live on literally zero grams of carbohydrates, though in reality there is always trace amounts in meat and vegetables. My optimal diet is around 5g of carbs per day. Unlike fats and proteins, there is no minimum level of dietary carbohydrates required to function.

The little amount the body requires can produce thanks to gluconeogenesis, and the vast majority of the energy is provided first by ketones then by free fatty acids after adaptation.

> You might chronically knock yourself out of keto without realizing it

Isn’t the keto flu something almost everyone experiences? That was always my understanding, so chronically knocking yourself out of ketosis would mean chronically being sick, I have a hard time believing people can do that without realizing it (and I’m one of the lucky ones where the process only takes a few days, it’s 1-2 weeks for my wife)

Not only my source, but me as well. I think it's plausible that e.g. keto (as in actually entering ketosis) could raise mortality but low carb diets could lower it, or that there's a confounding effect with dietary fibre, or that low carb diets usually involve increased processed meat intake, or [insert story here].

However, we're talking about general health advice. If you tell people to eat low carb diets, they eat less dietary fibre as a result, and some of them die, then your advice has killed them. Doesn't matter if there's some hypothetical better diet out there, until you've found it and proven it works.

> If you tell people to eat low carb diets, they eat less dietary fibre as a result

That’s not a given, I’ve actually started getting more fiber on keto than before.

That's not a given, it's the first two predicates of an illustrative example of how dietary advice is more complicated than "which diet is best?" If all three of those predicates hold true, then your advice has killed them, therefore all-cause mortality rate is important.

It doesn't matter what the exact reason for higher all-cause mortality rates on low carb diets is unless you can give people advice on how to avoid them. What's important is the outcome of giving the advice, not a theoretical ivory-tower diet that most of the population won't or can't eat.

That’s like saying you should never give any advice unless you exhaustively list all possible ways for someone to fuck up the implementation. Telling someone the pharmacy is on the other side of the street will raise mortality unless you also tell them that they should check for cars before crossing. And not run into cars. Or walls close to the pharmacy.

No. You should give advice that causes good outcomes. You don't need to do anything else.

We know that low carb diets have higher all-cause mortality. Because of this, telling people to eat low carb will (probably) cause a bad outcome. If we want a good outcome, we need to work out more specific advice.

To be clear, advice doesn't always have to be very specific. This particular advice needs to be improved, because it looks like it would kill more of them than current dietary advice. We can tell it would kill them because the meta-analysis several comments above shows an increase in all cause mortality.

This is not the same as telling people where the pharmacy is, because A) we have no studies at all about going to the pharmacy, B) people need to get important medicine from the pharmacy and going to it could plausibly lower mortality, and C) telling someone where to find a building is not lifelong public health advice and the risk for one person crossing one road is miniscule anyway.

So the part I objected to was not actually relevant for your argument.

yeah, obviously nutrition is far from being the only factor for their longevity and health in old age, but if you take the japanese diet, rice is a pretty major component in their calorie input...

The Japanese diet contains small portions of rice, which may translate into a major component of total calories because it is calorie dense

Like with most things food, portion control seems to be the biggest problem in the American Diet

For another perspective on the parent comment: I've gotten some use out of Ayurvedic* diet and lifestyle tips (hailing from ancient India). Here's a balanced article on a ketogenic diet detailing some of the modern science as well as one practitioner's take from an Ayurvedic perspective:

https://lifespa.com/diet-detox/diet/ketogenic-diet-ayurvedic...

*Ayurveda is cool — it's like a compendium of cause and effect relationships for foods and activities and their qualitative, subjective effects on the body and mind.

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