Study finds reducing carbs and replacing with fats leads to increased metabolism
nytimes.com
nytimes.com
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.
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 is interesting that the study authors highlight the higher energy expenditure as an advantage for weight loss, but do not seem to directly address that they did not observe this advantage during the 20 week study period.
[1] https://twitter.com/YoniFreedhoff/status/1062762047677571079
Studies have already shown that weight loss affects metabolic rates.
From the paper: "During the test phase, participants’ energy intake was adjusted periodically to maintain weight loss within 2 kg of the level achieved before randomization."
A key part of the study was that they fed the participants more or less each day to maintain weight.
In other words, there should not have been any weight change at all, as weight change would have confounded the results since weight loss is known to effect metabolism.
However, from a layman perspective, it seems like it would be nice to be able to collaborate the measure of increased metabolism not only through one method (doubly labeled water) but also through weight loss over time.
It's like having an inaccurate measuring stick and basing the results of a study solely on measurements made by that one stick, while at the same time making an effort to make sure that no other means of measuring exist.
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.
But still a very interesting point you make.
Maybe we should continue eating processed, insulin spiking, gut destroying foods and see how our body adapts next? (That's not sarcastic, just a proposal) How is our body adapting currently? (Diabetes is not an adaptation)
Also, between catabolic processes that destroy the body to keep it going and binge eating, there's a happy amount of fasting and cutting calories to a sustainable amount... lipogenesis, ULDLs, and VLDLs generally aren't good.
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.
That is, this study seems to claim that what you eat can impact your metabolism.
https://www.scientificamerican.com/article/6-years-after-the...
Here's a study: https://www.ncbi.nlm.nih.gov/pubmed/18842775
Here's another one: https://www.ncbi.nlm.nih.gov/pubmed/23535105
Another interesting finding is what happened with the Biggest Loser contestants: https://www.scientificamerican.com/article/6-years-after-the...
That group on average burned 2607 before the competition, but only about 2000 calories after the competition, even if they continued to do plenty of exercise afterwards. They also regained much of that lost weight.
Thin people shouldn't be giving dieting advice, because the obvious confounder is having a well functioning metabolism, whereas overweight people don't ;-) This is made worse by doctors doing it for the same reasons as everybody else. Until they get fat themselves, realizing only afterwards that gluttony wasn't the problem after all.
It is well known that the resting energy expenditure is a simple function of body composition, with no influence of age, gender or body weight [0]
The first study attributes the drop in energy expenditure to the non-resting energy expenditure, which isn't part of the metabolism. There is no saying that difference in energy expenditure isn't compensated for in real life situations, the study freely admits the difficulty in controlling for it.
The second study shows a drop of energy expenditure of a whopping 2%. Another explanation of the effect could just be that the formula they use to predict the resting metabolic rate is too simple, it literally only uses two variables: fat mass and fat free mass. You wouldn't expect such a simple formula to hold over a wide range of weights, it's surprising that it works so well, to within 2%, in the first place.
The third one, the Biggest Loser study, is the only one of the three that is just plain wrong. I'm very surprised to see it appear on Scientific American. In the study, they invent their own formula for the RMR by doing a multilinear regression in 4 variables on 14 subjects. This formula is different from the usual formulae and tellingly underestimates the caloric need of fat tissue (1.5 kcal/d/kg instead of 3.5 kcal/d/kg or 5.7 kcal/d/kg as in your second study). Then they apply that formula, which was calibrated only on the obese subjects, on the people after they lost weight and compare that to the measured RMR, instead of using a more standard formula, and interpret the difference as metabolic damage. No wonder it doesn't work. If you instead plug in the data in a more accepted formula, you see little difference with the measured metabolic rate. Heck, even I have massive metabolic damage according to that formula, their formula estimates my RMR at a whopping 2460 kcal/d, which isn't my total daily energy expenditure. The measured RMR in the article, 1903 kcal/d, wouldn't be unusual for people of that weight.
That study should have never gotten past peer review, and I don't know why it hasn't been retracted yet.
I don't understand the focus on metabolism anyway. Even if a damaged metabolism existed (it doesn't), that still wouldn't change anything if you ate less. The problem lies in a miscalibration between satiation and energy need, we should be figuring out why some people are more hungry than others, and what we can do to change that.
you don't think eg amenorrhea features?
I've seen videos of people who are actually trying long term calorie restriction to live longer and they look terrible.
It lead to very unhealthy habits.
As anecdotal evidence that's the Inuit diet.
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.
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.
>"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.
How so? Even their lowest carb diet was much higher than 20-30g per day.
This completely ignores any gut microbiome changes (and corresponding nutrient absorption changes that might occur) due to a change in diet.
Either way, they did not include a keto diet. Instead they used a "relatively low carb" diet of 20% carbs. Since ketosis is an entirely different metabolic state there is no reason to extrapolate from 50%-5% (keto). They have no theory so they need to actually measure this, and every single academic nutrition study I've ever seen on % carbohydrates in the diet fails to do it.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1373635/
> More recently, Willi et al. examined the efficacy and metabolic impact of a VLCARB in the treatment of morbidly obese adolescents [4]. Six adolescents weighing an average of 147.8 kg consumed the VLCARB (25 g of carbohydrate/day) for 8 weeks. The results indicated that the weight loss with VLCARB is rapid, consistent, and almost exclusively from body fat stores. Changes in lean body mass, as estimated from DEXA and urinary creatinine, were not significant over the term of treatment. Bioelectrical impedance measurements reflected a greater loss of lean body mass, but changes in total body fluid and electrolyte content, as a result of dietary ketosis, may complicate these measurements.
> Although more long-term studies are needed before a firm conclusion can be drawn, it appears, from most literature studied, that a VLCARB is, if anything, protective against muscle protein catabolism during energy restriction, provided that it contains adequate amounts of protein.
What? Maybe, but I think citation is needed there. The most widely popular keto diet, Atkins, doesn't say a thing about fasting - when you boil it down, and don't do any of the stupid carb-replacement recipe trickery that a lot of people do, Atkins equates to: take your normal meal with meat, starch, and vegetable, and stop making the starch, eat a little more vegetable if you want. Voila, there goes 500-1000 calories a day, more if you're eating starchy/sugary snacks. And you won't be hungry between meals. It's not rocket science.
Diabetic people actually need carbs as if they use insulin shots, they often get hypoglycemic. If you have an active lifestyle, your BG actually just replenishes your glycogen depots and possibly you don't have much excess fat anyway. So, live a healthy lifestyle and then a moderate diet will work just perfectly!
Anyway, fat deposits in moderate size are not a bad thing. In fact, in many cases, they save lives - the evolution did not invent them without a solid reason. Yes, excessive fat is bad for men as it's feminizing, but doesn't have a huge impact on women when you look at the studies. There's also a good reason why fat is not so easily mobilized.
Yes, a low carb diet makes people feel less hungry, so they eat less. A (supposedly) "normal" carb diet makes many people hungrier than they should be so they eat excessively.
I doubt you really feel that comfortable because then why wouldnt you eat like this all the time? Just that you are referring to it as a "fast" tells me you are craving food. If you ate less because you felt satiated, you wouldnt refer to it as a fast.
I don't even know what you are talking about regarding overeating fat. My experience is just cut out the grains and sugars and eat whatever else you want. If you crave fat, then you eat it. There is no overeating involved. That is the entire point, if you keep your carbs low enough you do not want to overeat anything. There is no self-control involved, in fact you need to sometimes force yourself to feel like eating for social/etc reasons.
There is also no need to purchase "fancy fats", you do probably have to prepare your own food though since sugar is added to everything prepared for you.
>"All these diets ignore the most recent scientific discovery - epigenetics!"
This is hardly recent, and while I'm sure it has some sort of relationship to a persons optimal diet, no one has any idea what that is.
All I did is stop eating bread and preparing my own food so there was no sugar in it. So this extreme diet you are talking about seems like a strawman to me.
>"people should eat quality foods aligned with their genetic and epigenetic profile"
No one knows what this would be.
> "Don't eat too much carbs, don't eat too much fats, don't eat too much meat"
Which your body lets you know via a satiated feeling without gaining undesirable weight. "Too much carbs" seems to be over 50-100 g/day for most people. If it wasn't, they wouldn't eat more than was healthy.
An all meat diet is perfectly healthy if it includes enough fat. You started off by saying that you can’t get anything but energy from fat and that you need more than energy to survive.
> You cannot get "macros" from fat - you get energy, but you need more than energy to survive.
That’s not true. If you eat fat as part of an all meat diet you’ll have enough energy and nutrition to survive without problems. I wouldn’t be too surprised if a diet that was mostly fat with some lean meat worked as well.
> If you don't get carbs, your body breaks muscle tissue to produce it. There's also evidence that muscle is burned first before fat deposits.
Neither of these are true either. If you’re fasting and you stop exercising you will lose muscle rapidly as it gets broken down but if you continue exercising you’ll lose fat and a very small amount of muscle, accelerating over time.
> Ketotards eat a huge amount of fat thinking they are providing nutrients. Yes, you need fats, just like you need carbs, but not in excess.
If you’re eating nothing but meat you do in fact need fat to get enough nutrients. Given that carbohydrates are unnecessary to a healthy diet and meat is also unnecessary any notion of excess that claims to be acultural is ridiculous.
> Meat has vitamins and minerals, too. I'm not against meat, I'm against overeating when you're 30+.
This is the first time you’ve mentioned age or overeating. Every statement of fact you’ve made has been wrong. What was the point of taking part in this discussion?
Anyway, I keep saying - surviving and thriving are two different things. I want to thrive, not just to survive. I get tired of people giving the Inuit as an example. Yes, they survive on predominantly fatty meat (although they eat starchy roots, too, okay, "ate" as they've modernized), but I don't want to be anything like them, sorry, no offense! There are many tribes who are healthier, look better, and eat plenty of starches! Here's a recent article [1] about a tribe, which loads on starches, and looks and functions better than the Inuit. :D
Food is information. Eating high-fat may give some immediate results, but we have no idea what's the effect in long-term - nobody has such diet, sorry!
Also, cite a study claiming that carbs are not necessary for health? You're making a mistake again and again - just like fats carry other nutrients such as vitamin K, D, etc., carbs also come in concert with many others. It's 2018 and it's clear to all camps that refined foods are empty. I'm not asking you to eat refined tapioca starch, I'm telling you that you should eat sweet potatoes, yams, beans, legumes, etc. Of course, there's no perfect food and many plants have natural anti-nutrients just like meat and dairy do, but, again, we've evolved to handle lectins and others decently not to mention that many cooking practices also evolved unknowingly to reduce the toxicity.
I am surprised that nobody here argues an obvious detriment of carbs - their role in the formation of endogenous AGEs (advanced glycation endproducts), but, of course, for their formation, you need protein, too. At the same time, animal products are rich in exogenous AGEs [2].
[1]: https://www.unilad.co.uk/life/life-of-indonesian-tribe-in-re...
So 100g of carbs seems like a reasonable number if you want to be sure that your subjects do not enter ketosis.
http://www.mendosa.com/stefansson1.htm
http://inhumanexperiment.blogspot.com/2009/09/two-brave-men-...
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?
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.
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.
Japanese people often have a good breakfast, but then eat maybe 5-700 kcal for lunch (in the form of a bentou) and maybe the same for dinner. Sometimes you get a set bentou at work and it often works out to about 1000 kcal -- but nobody I know who eats those ever eats dinner. They'll have a drink or two after work with whatever otoshi (side dish imposed on you as a cover charge in the drinking establishment) and maybe some snacks.
I feel the problem of the US is a cultural one which goes beyond the basic carb/fat split.
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.
https://www.reddit.com/r/nutrition/comments/9x47lg/are_simpl...
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.
The problem is that people are eating candy bars, sugared soda, potato chips, french fries, pop tarts, and basically crap.
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.