In case anyone is interested, this thread includes a more specific set of methodological critiques made by Dr. Kevin Hall at this week's ObesityWeek conference (unfortunately does not include Dr. Ludwig's rebuttal):
https://twitter.com/YoniFreedhoff/status/1062760576869371910
Hall's research focus is on mathematical metabolism models, so his critique comes from that angle: it is possible doubly-labeled water measurements of energy expenditure may behave differently in a lower-carb environment, so the observed EE difference may not be meaningful. Ludwig actually briefly addresses this in their published paper, citing a few other studies suggesting that DLW is accurate and carb intake does not mess with isotopic measurements.
Hard to tell if this is a meaningful advance for the low-carb crowd, or just an artifact of insufficiently validated methodology.
I am interested in what the article did not say, as it may shed some light on this critique. Specifically, the weight differences between the groups at the end of the second phase of the study.
The second phase of the study involved breaking the participants into three groups. They were fed the same number of calories. Each group had several biomarkers tracked. This included daily calories burned and ghrelin (a hormone) levels. I understand the critique targets the measurement of calories burned, via the doubly labeled water measurement of the metabolic date.
What I wonder is what the average weight change was for each of the three groups after 5 months. If the claim is that the high-fat diet group burned an average of 250 calories more, then that should be reflected in an additional weight loss of about 10 pounds (250 calories per day * 5 months * 30 days in a month / 3700 calories in 1 pound of fat). This would be because all the people across all groups were fed the same number of calories. If one group used 250 calories more per day, these extra calories had to come from somewhere. They would have to come from fat stores and muscle tissue inside of the body, resulting in a weight loss.
If the weight loss for that group correlates with the doubly labeled water measurement then it gives more credence to the study's results. If it does not correlate with weight loss, it is suspicious to claim that one group of people burned 250 more calories than the other over 5 months while eating the same number of calories but did not lose any weight.
> It found that overweight adults who cut carbohydrates from their diets and replaced them with fat sharply increased their metabolisms. After five months on the diet, their bodies burned roughly 250 calories more per day than people who ate a high-carb, low-fat diet
Is it healthy in the long term to increase metabolism like this? Animal studies strongly suggest that calorie restriction is beneficial to longevity, and there is anecdotal evidence in humans (e.g. Okinawans). A higher resting metabolism means more aerobic respiration, which generates reactive oxygen species, which damages cells. Better to go the hard way and simply eat less.
It depends on the medical problems the individual is facing.
Overweight people have the problem of a low metabolism due to diets. Which is why diets stop working.
So in them, no, a low metabolism isn’t OK, especially because that low metabolism isn’t correlated with hunger signals.
Speaking of animal studies there’s also this idea that in nature everything is cyclical. You’ve got periods of feasting and you’ve got periods of famine. Eating less all the time is probably not good for longevity.
I'm not an expert in this, but the historical Okinawa diet doesn't have as much in simple carbohydrates compared to other lifestyles[1]. I think calorie intake is a notable aspect like you mentioned, but eating foods with a higher satiety strikes me as making a larger impact as well.
Some of the best things in life involved expending a lot of calories. Even if calorie restriction "works" in the sense of slightly extending human lifespan (and there's no real evidence for that yet) it's hard to see that as a net improvement.
I've seen videos of people who are actually trying long term calorie restriction to live longer and they look terrible.
From a much broader, evolutionary or theory-of-life perspective.. eating less would a be a step backwards, towards eating nothing - not existing, or pure entropic. Every advance in the development of life is a fight against entropic death- as organisms move farther and farther from this, there will be increasing forces of nature fighting in the opposite direction - that is a sign you are moving in the RIGHT direction.
>> The trial cost $12 million and was supported largely by a grant from the Nutrition Science Initiative, a nonprofit research group co-founded by Gary Taubes, a science and health journalist and proponent of low-carbohydrate diets.
So, a non-profit funded by a gentleman who advocates for low-carbohydrate diets found that low-carbohydrate diets are good for you.
That's the beauty of science: it doesn't matter what it looks like. It only matters what it is. I'd learn how to critically read a scientific study paper, if you don't know how already. You're just begging to be lied to if you don't.
Wow, another study that fails to actually include a low carb diet:
>"During the test phase, high, moderate, and low carbohydrate diets varied in carbohydrate (60%, 40%, and 20% of total energy, respectively)"
A low carb diet is going to be 100g (~ 400 cal or 20% caloric intake) per day at the absolute maximum. Really it should be half to a quarter of that and you will not feel the need to restrict your eating at all. The way it works for getting to a normal weight is that you feel less hungry if you limit your carb intake to those levels.
It's amazing how awful this academic nutrition research is, they just make up their own false definitions about things then draw conclusions about what people care about.
Keto diet is ideally no more than 20-30g of carbs per day, with the majority of your calories coming from fat macros. This study would explain why keto enables shedding body fat so quickly (which is usually waived away, by myself included, as satiation from fats and protein vs carbs).
Given an average human consumption of 2250 calories per day, they're telling us that we could feed ~10% fewer people if we moved to a fat-based diet globally?
Depends where the fats come from. It takes a lot more resources to grow 100 calories of animal than 100 calories of plant. I imagine there is still a significant difference of resources needed to produce 100 calories of plant-based fat and 100 calories of animal-based fat.
You would think so, but thermodynamics do not apply to these scientists. People on an isocaloric high fat diet will expend 10 % more calories without loosing weight (their claim). I'm smelling the beginning of a perpetual motion machine.
Yes, an engine burning through more fuel will deteriorate faster. Carbs are easy fuel that won't wear out the system as much as having to process fats and protein for that same energy benefit.
The nutritional science community is generally weak on data, because humans are expensive to study. This has led to prominent scientists cherry picking bad data and using correlation to back up shitty hypotheses. The Dr. Hall quoted in the article is a classic example of this. Attacking the study wherever he can, because it demonstrates how crappy his lifetime of low fat diet studies actually are.
It’s not clear to me how any of this is new.
What id like to hear is how researchers reconcile this concept with what is seen certain other countries, mostly Asian, where rice is a staple of their diet, and where you don’t see the levels of obesity we have in the US.
Sugars in general, and high-fructose corn syrup in particular. It is added to a lot of products in the US "to make them more pallatable". Which is an euphemism for "to sell more".
Rice is carbs, yes. But it also fills the stomach (for a while, at least - beans are better and proteins are much better on that field). Sugar/Syrup has the opposite effect. It is addictive and it makes you crave for more. It is also very cheap. So food vendors add it to everything - to sell you more. Meat. Cheese. To me (from Europe) US bread tastes like cake.
European and Asian food producers are gradually catching up on this strategy and are adding extra sugars, so the obesity levels are also increasing, especially in big cities:
To me doesn't make sense that something so unhealthy as corn syrup (and other sugars) isn't more heavily taxed. Right now food producers are making their buck by passing the bill to the US health care, which is a big chunk of the US central budget (and also very inefficient). It's a drag on the whole US economy, in addition of causing a lot of human tragedy.
In my country (France) bread used to be a staple of the diet and there was no obesity epidemic at the time.
Perhaps it has to do with total food intake. I live in Bangkok at the moment, rice is a staple food and Thais eat all the time (they remind me of Hobbits). Portions are small though, so perhaps that's why I don't see a lot of overweight people.
It seems that the carbohydrate intake in these study is mostly based on processed carbohydrates, which are distinguished from unprocessed/lesser processed ones (like beans, fruits, and to a lesser extent rice). Those make a huge difference for our metabolism compared to white flour or industrial sugar. Fruits may contain a lot of sugar as well but it seems to make a big difference if sugar comes with fibres or not.
I think we do a disservice to people to lump all carbs together. For many, it makes any dietary change seem overwhelming. I doubt many people are getting fat eating a diet of fish, veggies, and rice. In fact, that sounds like a healthy meal.
The problem is that people are eating candy bars, sugared soda, potato chips, french fries, pop tarts, and basically crap.
It's about portions when eating Asian food in Singapore my rice always used to finish before the proteins that come with a dish so I sometimes ordered extra rice. Plus Asian food have lots of soups on the sides so I think their carbohydrate and protein intake is more balanced then it looks.
What this article says is true and has been known for quite some time. (Not exactly sure why it's so revalatory in the article)
I've also tried it for years as well to lose and keep weight down. But it's actually not healthy for you. You're better off eating a balanced diet, not too much of it, and exercising.
[+] [-] willsun|7 years ago|reply
Hall's research focus is on mathematical metabolism models, so his critique comes from that angle: it is possible doubly-labeled water measurements of energy expenditure may behave differently in a lower-carb environment, so the observed EE difference may not be meaningful. Ludwig actually briefly addresses this in their published paper, citing a few other studies suggesting that DLW is accurate and carb intake does not mess with isotopic measurements.
Hard to tell if this is a meaningful advance for the low-carb crowd, or just an artifact of insufficiently validated methodology.
[+] [-] koliber|7 years ago|reply
The second phase of the study involved breaking the participants into three groups. They were fed the same number of calories. Each group had several biomarkers tracked. This included daily calories burned and ghrelin (a hormone) levels. I understand the critique targets the measurement of calories burned, via the doubly labeled water measurement of the metabolic date.
What I wonder is what the average weight change was for each of the three groups after 5 months. If the claim is that the high-fat diet group burned an average of 250 calories more, then that should be reflected in an additional weight loss of about 10 pounds (250 calories per day * 5 months * 30 days in a month / 3700 calories in 1 pound of fat). This would be because all the people across all groups were fed the same number of calories. If one group used 250 calories more per day, these extra calories had to come from somewhere. They would have to come from fat stores and muscle tissue inside of the body, resulting in a weight loss.
If the weight loss for that group correlates with the doubly labeled water measurement then it gives more credence to the study's results. If it does not correlate with weight loss, it is suspicious to claim that one group of people burned 250 more calories than the other over 5 months while eating the same number of calories but did not lose any weight.
[+] [-] dnhz|7 years ago|reply
Is it healthy in the long term to increase metabolism like this? Animal studies strongly suggest that calorie restriction is beneficial to longevity, and there is anecdotal evidence in humans (e.g. Okinawans). A higher resting metabolism means more aerobic respiration, which generates reactive oxygen species, which damages cells. Better to go the hard way and simply eat less.
[+] [-] bad_user|7 years ago|reply
Overweight people have the problem of a low metabolism due to diets. Which is why diets stop working. So in them, no, a low metabolism isn’t OK, especially because that low metabolism isn’t correlated with hunger signals.
Speaking of animal studies there’s also this idea that in nature everything is cyclical. You’ve got periods of feasting and you’ve got periods of famine. Eating less all the time is probably not good for longevity.
[+] [-] danbolt|7 years ago|reply
https://en.wikipedia.org/wiki/Okinawa_diet
[+] [-] JPKab|7 years ago|reply
But still a very interesting point you make.
[+] [-] nradov|7 years ago|reply
I've seen videos of people who are actually trying long term calorie restriction to live longer and they look terrible.
[+] [-] Shorel|7 years ago|reply
As anecdotal evidence that's the Inuit diet.
[+] [-] chmike|7 years ago|reply
[+] [-] hammock|7 years ago|reply
[+] [-] YeGoblynQueenne|7 years ago|reply
So, a non-profit funded by a gentleman who advocates for low-carbohydrate diets found that low-carbohydrate diets are good for you.
That just don't sound like an unbiased study.
[+] [-] matwood|7 years ago|reply
The study looks well run. Because someone paid for a study does not automatically make it biased.
Everyone has biases. In the classic sense, attack the argument and not the debater.
[+] [-] Gatsky|7 years ago|reply
[+] [-] lj3|7 years ago|reply
[+] [-] tptacek|7 years ago|reply
[+] [-] nonbel|7 years ago|reply
>"During the test phase, high, moderate, and low carbohydrate diets varied in carbohydrate (60%, 40%, and 20% of total energy, respectively)"
A low carb diet is going to be 100g (~ 400 cal or 20% caloric intake) per day at the absolute maximum. Really it should be half to a quarter of that and you will not feel the need to restrict your eating at all. The way it works for getting to a normal weight is that you feel less hungry if you limit your carb intake to those levels.
It's amazing how awful this academic nutrition research is, they just make up their own false definitions about things then draw conclusions about what people care about.
[+] [-] randomThoughts9|7 years ago|reply
So 100g of carbs seems like a reasonable number if you want to be sure that your subjects do not enter ketosis.
[+] [-] toomuchtodo|7 years ago|reply
[+] [-] goldfeld|7 years ago|reply
[+] [-] someone454|7 years ago|reply
[+] [-] rawoke083600|7 years ago|reply
[+] [-] bencollier49|7 years ago|reply
Given an average human consumption of 2250 calories per day, they're telling us that we could feed ~10% fewer people if we moved to a fat-based diet globally?
[+] [-] koliber|7 years ago|reply
[+] [-] jfoldager|7 years ago|reply
[+] [-] scotty79|7 years ago|reply
[+] [-] goldfeld|7 years ago|reply
[+] [-] ckdarby|7 years ago|reply
[+] [-] JPKab|7 years ago|reply
The nutritional science community is generally weak on data, because humans are expensive to study. This has led to prominent scientists cherry picking bad data and using correlation to back up shitty hypotheses. The Dr. Hall quoted in the article is a classic example of this. Attacking the study wherever he can, because it demonstrates how crappy his lifetime of low fat diet studies actually are.
[+] [-] dr_|7 years ago|reply
[+] [-] otikik|7 years ago|reply
Rice is carbs, yes. But it also fills the stomach (for a while, at least - beans are better and proteins are much better on that field). Sugar/Syrup has the opposite effect. It is addictive and it makes you crave for more. It is also very cheap. So food vendors add it to everything - to sell you more. Meat. Cheese. To me (from Europe) US bread tastes like cake.
European and Asian food producers are gradually catching up on this strategy and are adding extra sugars, so the obesity levels are also increasing, especially in big cities:
https://en.wikipedia.org/wiki/Obesity_in_China
It just has not reached US levels.
To me doesn't make sense that something so unhealthy as corn syrup (and other sugars) isn't more heavily taxed. Right now food producers are making their buck by passing the bill to the US health care, which is a big chunk of the US central budget (and also very inefficient). It's a drag on the whole US economy, in addition of causing a lot of human tragedy.
[+] [-] draven|7 years ago|reply
Perhaps it has to do with total food intake. I live in Bangkok at the moment, rice is a staple food and Thais eat all the time (they remind me of Hobbits). Portions are small though, so perhaps that's why I don't see a lot of overweight people.
[+] [-] HelenePhisher|7 years ago|reply
[+] [-] riffraff|7 years ago|reply
I feel the problem of the US is a cultural one which goes beyond the basic carb/fat split.
[+] [-] matwood|7 years ago|reply
The problem is that people are eating candy bars, sugared soda, potato chips, french fries, pop tarts, and basically crap.
[+] [-] mtgx|7 years ago|reply
https://www.reddit.com/r/nutrition/comments/9x47lg/are_simpl...
[+] [-] xbmcuser|7 years ago|reply
[+] [-] bad_user|7 years ago|reply
Healthy Asian populations also eat a lot of fish and seaweed. They eat much more salt (!) than we do. And they don’t eat so much junk food.
[+] [-] sridca|7 years ago|reply
[+] [-] nikolay|7 years ago|reply
[+] [-] anonu|7 years ago|reply
I've also tried it for years as well to lose and keep weight down. But it's actually not healthy for you. You're better off eating a balanced diet, not too much of it, and exercising.
[+] [-] zackbloom|7 years ago|reply
[+] [-] boringusername|7 years ago|reply
[+] [-] captainbland|7 years ago|reply
[+] [-] stevew20|7 years ago|reply
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