So, I always cringe a little when I read medical conclusions in the mainstream media. And I'll be upfront. I'm probably biased on the side of medicine on this one. I'm a former nephrologist.
The one study this person mentions by name (and dismisses) is the DASH-Sodium Study.
"Like the previous study, it was based on a large sample (412 participants) and was a multi-center, randomized, outpatient feeding study where the subjects were given all their food."
"The DASH-Sodium study found that reductions in sodium intake produced significantly lower systolic and diastolic blood pressures in both the control and DASH diets. Study results indicate that the quantity of dietary sodium in the control diet was twice as powerful in its effect on blood pressure as it was in the DASH diet."
So, positive conclusions (lower salt -> lower blood pressure) in a seemingly well designed study. People were randomized, it was prospective, and people given all their food. So, change one thing and see what happens.
The author here seems to cite other studies to make the opposing case (low salt = bad), but doesn't give exact references. I did a quick google search and found this one: http://www.nytimes.com/2011/05/04/health/research/04salt.htm... But you can already tell it's an inferior study. "It involved only those without high blood pressure at the start, was observational, considered at best suggestive and not conclusive."
So, let's try to compare apples to apples.
He points out that the DASH study didn't conclude anything about death or cardiovascular disease. Yes, that's true. So sure, there's a chance that despite blood pressure reductions a low salt diet could cause problems. But it's not the obvious conclusion. Anyone have any solid studies on this?
"The associations between systolic pressure and sodium excretion did not translate into less morbidity or improved survival. On the contrary, low sodium excretion predicted higher cardiovascular mortality."
> He points out that the DASH study didn't conclude anything about death or cardiovascular disease. Yes, that's true. So sure, there's a chance that despite blood pressure reductions a low salt diet could cause problems. But it's not the obvious conclusion.
That's the whole point, you say it yourself. The idea that "salt is bad" has just as shaky underpinnings as "lower blood pressure is good". The only thing we care about is death or disease, not lowering blood pressure. So even if less salt = lower blood pressure, that doesn't tell us if this is good, or harmful.
The obvious conclusion is that there is no conclusion.
> The idea that "salt is bad" has just as shaky underpinnings as "lower blood pressure is good".
Wait, "lower blood pressure is good" has shaky underpinnings? Is there a debate on that? I don't think there's a debate that high blood pressure results in worse (death/disease) outcomes.
"Wait, "lower blood pressure is good" has shaky underpinnings? Is there a debate on that? I don't think there's a debate that high blood pressure results in worse (death/disease) outcomes."
There's no debate that high blood is associated with heart disease. There's always "a debate" if you try to go from correlation to cause. You always have to be careful this.
You have to show that a particular mechanism for lowering blood pressure results in better outcomes. You can't unambiguously say "we've lowered the blood pressure, we know the results will be better now".
"There's no debate that high blood is associated with heart disease. There's always "a debate" if you try to go from correlation to cause. You always have to be careful this."
I always thought that high blood pressure was caused by destruction of the lining of the arteries, and stiffening of the tissue, rather than water retention.
Control of blood pressure is dependent on this delicate balance of tissues against the pumping of the heart, as well as production of the substances that allow you to be sexually active.
Hence the fortuitous discovery of Viagra whilst searching for blood pressure control medications.
I acknowledge that jumping from a to b to c (low salt to low blood pressure to less death) has gaps in causality. But why do you not take objection to his uncited assertions that low salt intake and bad outcomes together imply causality?
So then it sounds like one might say that lower blood pressure isn't necessarily good unless you already have high blood pressure (or are on the cusp of having high blood pressure)?
Populations with low sodium intake, and other factors, have no hypertension, and low rates of death and disease from heart disease.
The randomized studies have found lower death and disease from lower sodium. So far the probability that this is just chance is about 10%. So the standard p number is not reached.
The most likely outcome is that a bigger better studies will produce significance.
Thank you for such precision concerning statistical semantics.
But I also find the non-experimental data compelling. I think more long term data will clear this up eventually.
It is urgent that we solve foundational debates in statistics. The health and economies of the world hang on this very point. So far Judea Pearl's work is the most compelling I've found. Do you have any references you'd suggest?
Because kidney function is damaged by pressure but its control mechanisms are governed by osmolarity (flow). A high pressure, low-flow kidney will send signals to the body to increase BP further, until the kidney essentially annihilates itself. You've got to unload the kidney down to a reasonable level, while keeping sufficient pressure to perfuse the heart and brain. In the setting of cardiovascular disease (stiff pipes with reduced cross-sectional area), the safe range becomes progressively narrower.
> I always cringe a little when I read medical conclusions in the mainstream media.
I usually do too, especially articles about nutrition which are notoriously unreliable due to the near complete lack of randomized, controlled, prospective studies and the abundance of observational studies, but this one doesn't seem too bad. In fact, the same author published a similar article in Science last millennium http://www.stat.berkeley.edu/users/rice/Stat2/salt.html so I don't think you can blame the mainstream media too much here if they're just printing an article similar to what would satisfy Science's editorial standards.
If you look at the numbers in the Wiki link you provided, the reduction in BP in DASH dieters was small in non-hypertensives and not exactly huge in hypertensives.
"Respectively, the DASH or “combination” diet lowered blood pressures by an average of 5.5 and 3.0 mm Hg for systolic and diastolic, compared with the control diet. The minority portion of the study sample and the hypertensive portion both showed the largest reductions in blood pressure from the combination diet against the control diet. The hypertensive subjects experienced a drop of 11.4 mm Hg in their systolic and 5.5 mm Hg in their diastolic phases."
I question whether the 5.5/3 mmHg is really worth eating bland low sodium food. Statistical significance does not necessarily imply clinical significance, and you're asking people to give up something pretty big. Willpower is a limited resource. We should have good reasons to ask people to use it up.
I'd agree. I have had times in my life where I have had to increase my salt consumption to avoid problems. These include everything from altitude sickness to dehydration caused by eating a diet too high in fruit.
However, at the same time I don't think that things are as clear-cut as in the article. One of the serious issues we find in current dietary trends is that we eat more prepared foods which tend to be high in salt, hydrogenated oils, and sugars.
So I personally side both with the idea that we have gone overboard in trying to reduce salt and also the idea that the modern American diet tends towards too much salt. I would also make the somewhat controversial argument that I think that anything we replace salt with will be even worse. The solution is to eat more fresh foods and fewer junk foods and prepared foods, not try to engineer some sort of low sodium equivalents.
there's a chance that despite blood pressure reductions a low salt diet could cause problems
For that matter, there's a chance that because of blood pressure reductions, a low salt diet could cause problems -- if the kidneys respond to low blood pressure by secreting renin, and renin causes more cardiovascular damage than high blood pressure.
I believe the contention is that studies like DASH show that changes in sodium consumption, rather than levels of sodium consumption, can effect blood pressure. That is, if you go onto a low sodium diet your blood pressure will fall, but then rise again to its previous level as your body adjusts.
Taubes has written a bit about salt before. Unfortunately, the only thing he's written that I can find that goes into more detail is this Science news focus article:
It talks about the DASH study and some others in a little more detail, but unfortunately it's 14 years old now, so I don't know what research has been done since.
arn, thanks for leading this one! Let me chime in that salt no doubt drives caloric intake. One need look no further than chefs and fast food to figure that out. So, in my mind, salt is a double whammy: BP and a secondary cause of weight gain, cholesterol, and everything else that comes with weight gain.
As someone who has lost around 40 pounds of fat switching to the high fat paleo diet I'm not at all surprised that the current state of the conventional wisdom on food is wrong in any number of ways. It is funny that we really have no idea what we should be eating naturally at all.
Grains were making me sick and I didn't notice for years. It wasn't until I read a book listing side effects of grain consumption that I considered that the grains were the cause of my problems.
One of the most interesting things is how many sciences inform archaeology, and how few sciences are willing to be informed by archaeology.
High grain diets archaeologically are associated with increased tooth decay and tooth loss rates and lower life-expectancy than high-meat and high-dairy diets. Overly high dairy diets are associated with anemia (probably because cow milk decreases the ability of humans to absorb iron from foods). The Vikings were eating butter smeared on dried fish for breakfast and living significantly longer (and with very low rates of dental caries) than the grain-eating Continental Europeans of the same time. Indeed a Scandinavian living to 5 could expect to live to an older age than a Frenchman living to 20 despite the fact that life expectancy was so heavily slanted by childhood deaths in both cases.
Our conventional wisdom of nutrition is basically plausible hypothesis... if you ignore anything interdisciplenary. I think the archeologists know more about the effects of nutrition on the human body today than anyone else.
It should be noted that the author of the linked article is Gary Taubes, who is best known for Good Calories, Bad Calories, a book that seeks to turn the conventional wisdom of nutrition on its head.
I loved GCBC, but unfortunately Taubes goes a little bit too far near the end in condemning carbohydrates. It's really hard to recommend the book because of that overreaching.
A little too far is an understatement. I read GCBC when it came out and found its arguments compelling at the time. After learning more, I've reversed my opinion almost completely.
James Krieger's critique of the core chapter of GCBC is very worthwhile reading: http://weightology.net/?p=265. His blog also has other articles addressing the core Atkins-Taubes thesis of the link between insulin, carbs and obesity. Alan Aragon's Research Reviews had an Editor's Cut on Taubes, as well as pieces specifically on the role of insulin and carbs in obesity and weight gain, but unfortunately all that is subscriber-only. Lyle McDonald (who literally wrote the book on ketogenic diets) has also written a lot on that whole orbit of ideas--never an article against GCBC directly, though he has certainly expressed his negative opinion of it on many occasions.
However, I think most of the book is still worth reading, especially the history behind the demonitization of fat and the uselessness of "calories in, calories out." Taubes is at his best as a science historian and, obviously, not a scientist.
There's nothing useless about energy balance. It can be misinterpreted and misapplied, but Taubes throws the baby out with the bathwater and pretends it doesn't apply at all. For example, classical low-carber mythology is that on a low-carb diet you can eat virtually unlimited calories (as usually defined) and maintain weight, if perhaps not lose weight outright. As an example, there's an old post on Michael Eades's blog where he talks of a small woman allegedly eating 5000 calories and maintaining her weight. As explained in James Krieger's article, people's reports of their own calorie intake for studies have consistently been found to be way off the mark, to the point of being useless. When you actually measure what is being eaten under clinical conditions, the result is in line with the conventional theory of energy balance.
The main benefit of low-carb diets for weight loss is that they spontaneously reduce calorie intake by cutting out whole groups of foods (by looking at studies it's been shown that any diet that restricts food choices like this will tend to induce weight loss but is usually unsustainable), and especially lots of highly palatable foods (to use Guyenet's terminology). But most longer-term comparative studies of diets that look at the performance past the 12-month mark show that low-carb diets don't fare any better on average than other standard weight-loss diets. The one exception is a study the low-carbers like to hold up as a vindication of their views; Lyle McDonald addresses that one here: http://www.bodyrecomposition.com/research-review/comparison-....
>There's nothing useless about energy balance. It can be misinterpreted and misapplied, but Taubes throws the baby out with the bathwater and pretends it doesn't apply at all. For example, classical low-carber mythology is that on a low-carb diet you can eat virtually unlimited calories (as usually defined) and maintain weight, if perhaps not lose weight outright.
On the last point, of course it's wrong. I never saw Taubes deny CICO as being true. He repeatedly states that, while true, it isn't useful for answering _why_ people get fat.
It's as if I asked why some people are rich and others are poor. And you simply said that the poor people spent more money than they took in. It's true and yet utterly useless if you keep harping on that single point while ignoring inheritance, education, mental illness, drug abuse etc.
You've further convinced me not to recommend GCBC to anyone, since I keep realizing its possible for people to miss the central point of the book.
I'm totally in agreement on Guyenet's stuff, but he agrees with Taubes on CICO being not helpful:
>This is where I agree with Taubes-- 1) the key thing to understand is what is causing the energy imbalance, and 2) the idea that "eat less, move more" is a practical fat loss strategy does not necessarily follow from the first law of thermodynamics. Taking in less energy and expending more does cause fat loss, but the problem is that it's difficult to maintain-- the body opposes changes in its fat stores.
No. Low-carber thesis is that raising intake of fats suppresses appetite so you can eat what you like until you are full. The idea is carbs keep you hungry because of energy partiioning and so you over consume calories because you feel hungrier than you should. Taubes explains this very well in What Makes us Fat.
His main claim is that the energy balance problem is a consequence of getting fat, not the cause.
You don't mention insulin by name, but that's what underlies Taubes's thesis about the link being carbs and obesity. James Krieger dispels much of that argument here: http://weightology.net/weightologyweekly/?page_id=319
> Low-carber thesis is that raising intake of fats suppresses appetite so you can eat what you like until you are full.
Eating pounds of fruits and vegetables won't you make you full? Or rice and potatoes for that matter? Eating pounds of lean protein sources like tuna and chicken breast won't make you full?
> The idea is carbs keep you hungry because of energy partiioning and so you over consume calories because you feel hungrier than you should.
That isn't borne out by the evidence. The demonization of one macronutrient over another is baffling. If you subsist on calorically dense processed foods that are purposefully engineered to be high in palatability then you are more likely to overeat. Carbs aren't the problem. Neither is fat; dietary fat is very calorically dense, so it's easy to get lots of "hidden" calories from it, but that's the main downside from a weight loss perspective.
>Eating pounds of fruits and vegetables won't you make you full? Or rice and potatoes for that matter? Eating pounds of lean protein sources like tuna and chicken breast won't make you full? Of course it will.
I didn't claim otherwise
Fat accumulates due to an excess of calories. But this isn't the cause of us getting obese, it's a proximal cause, not the ultimate cause. What causes us to eat more calories than our bodies require?
> What causes us to eat more calories than our bodies require?
One big reason is eating foods that aren't filling relative to the energy and nutrients they provide. There's nothing unique about carbs in that regard. I can barely put away a 1000-calorie meal with an equal amount of calories from chicken breast and white rice (100+ grams of carbs just from the rice). Putting away the same amount of calories split between chicken breast and greens would be almost physically impossible--I ate a whole pound of grilled asparagus with my chicken breast on Sunday, and the asparagus barely amounted to 100 calories. But I can easily put away a 2000-calorie pepperoni pizza with extra cheese. If you think carbs are the calorically-dominant macronutrient in that pizza, think again. I'm not blaming the fat either. My point is that the issue goes much deeper than simple macronutrient composition.
Fats and proteins are more filling and satisfying per gram than carbs.
The pizza example you give is basically wrong. Carbs would be the largest source of calories. For example see http://nutritiondata.self.com/facts/fast-foods-generic/9307/... which is for a 2500 calorie pepperoni pizza. Almost half the calories come from carbs.
> Fats and proteins are more filling and satisfying per gram than carbs.
Again, that statement makes no sense. You don't eat carbs, fats and proteins. You eat foods. Is 100 calories of olive oil as filling as 100 calories of asparagus (about a pound)? If that's too extreme, I'd still gladly put up your 100 calories of olive oil (a few spoonfuls) against my 100 calories of white rice (a small bowl) for satiety and fullness.
Different macronutrients stimulate hormones differently, so I'm not saying that macronutrient composition doesn't play a role in these matters, only that those effects are mostly irrelevant if you don't go overboard. For example, high GI and low GI foods have virtually identical glycemic loads when consumed alongside a lean protein like chicken breast (GI is measured by feeding food to a subject after a 12-hour fast), so even if you accept that insulin is the master regulator of fat storage (which is out of date nonsense that Taubes can't get out of his head), it still wouldn't matter appreciably so long as you eat your carbs alongside your fiber and protein.
> The pizza example you give is basically wrong.
I was going by the pizza recipe I usually make at home, which per slice has 200 calories from fat and 100 from carbs.
You seem to know what you're talking about. Is there a book, author, or website you'd recommend for getting a primer on nutrition? Many of my friends are doing paleo diets, juice diets, no-carb diets and all of them have pseudo scientific sounding explanations and bestselling books espousing them.
I don't personally need to lose any weight (in fact I could stand to gain a few) but I am still curious about how the food I eat is affecting my body. With everyone yelling different sets of "facts", it's hard to know where to even start.
Lyle McDonald is the best source out there. His website at http://bodyrecomposition.com has a near-endless wealth of articles. Alan Aragon's work (http://alanaragon.com/) is on a similar level, and in many ways he's a kinder, gentler version of Lyle. However, his best stuff is only available as part of his subscriber-only Alan Aragon's Research Review. James Krieger is another one whose website at http://weightology.net I already referenced elsewhere in this thread.
As a rule, the people whose work I lean on are those with both a deep knowledge of the underlying theory as well as clinical experience working with a range of athletes and non-athletes. Of course, you should never trust anyone unconditionally and always evaluate their reasoning on its own intrinsic merits. Someone like Charles Poliquin seemingly fits my description, but he makes most of his money from selling supplements and is always pushing his products--he recommends that you consume massive doses of his insanely overpriced fish oil, rub licorice cream on your abdomen for spot-reduction fat loss, etc--so everything he says must be taken with a truckload of salt.
People like Robb Wolf and Mathieu Lalonde from the paleo community also fit my desiderata. You can learn a lot from them, so long as you keep in mind that most of their clinical inferences are so far by necessity based mostly on anecdotal data rather than controlled studies. There are also some general issues to keep in mind with the ancestral dietary approach as generally preached and practiced. There's an underlying assumption that the ancestral diet was far more uniform across cultures than the evidence shows. They also tend to downplay the evidence that grain consumption has been around for much longer than 10,000 years, indeed closer to 100,000 years, giving plenty of time for many physiological adaptations to have taken place. Stuff like that. As with everyone with strong commitments to a specific point of view, their analysis is often subject to confirmation bias. A classic case would be Robb's analysis of the traditional Okinawan diet where he completely downplayed the very high levels of carbs consumption via rice by giving virtually all the credit for the health benefits to the fatty fish consumption.
His statement was on a per-gram basis, which seems pretty much obviously true (since it basically says that fat is more energy-dense than carbs).
Nonetheless, like jcheng I'm interested in what you've learned from your research. I've also been looking into low-carb/ketogenic diets, and a friend does intermittent fasting (IF), and there are a host of clashing opinions and studies of varying quality on everything. Taubes, Lustig, Aragorn...my conclusion is that we still know very little about the effects of diet composition.
I've switched mostly to sugar substitutes and reduced my carb intake because it seems like something most would agree upon. My IFing friend claims IF/caloric restriction is one of the few things actually shown to significantly prolong lifespans in animals. Do you have any knowledge of these things, or of better-done studies I should be reading? Thanks.
edit: I've just been reading Guyenet and what he says is quite interesting
> His statement was on a per-gram basis, which seems pretty much obviously true
Ah, I missed that. But that's not very a useful comparion. The useful thing to do is comparing calorically matched portions of fat-based and carb-based foods for satiety and fullness.
One problems with carbs though, particularly carbs that break down fast in the body (say, rice or honey) is that they do cause insulin spikes and blood sugar drops, which can often lead to additional consumption. Carbs are unique in this regard though to varying degrees: coconut sugar seems to have very little of this effect while rice is very bad. There's a reason why Chinese food is associated with folks being hungry an hour after eating.
However, I think the real harm comes from combining the carb boom-and-bust blood sugar cycle with high diets where it's easy to eat lots of calories, and when you add a sedentary life style by historical terms, it gets even worse.
A hundred and fifty years ago, the average Irish peasant would have eaten 12 pounds of potatoes every day. That's almost 5000 calories just from the potatoes (and now add a small amount of dairy, veggies, and eggs).
So it's not just one thing. It's the emphasis on carbs, the concentrated energy foods, and the fact that we drive in cars and dont walk that much and certainly don't try to grow our own food in marginal rocky soil.....
Edit: I always wondered why Javanese food is traditionally so sweet without a lot of people being obese. It turns out that the biggest sweatener used is coconut sugar, which has a glycemic index of something like 35. That's a bit higher than whole barley but quite a bit lower than wheat.....
What causes us to eat more calories than our bodies require?
Remember that your body doesn't care that you want to look good on the beach. It wants to load up when times are good, incase there is a famine around the corner. Piling on the pounds is a survival mechanism, people who tend towards fat are in fact highly tuned survival machines.
It's too soon to tell if this is still a useful mechanism. Mankind has only been "civilized" for a heartbeat in evolutionary time. Nevertheless, if you want to shed fat, the key is to convince your body that starvation is not around the corner.
Eating pounds of fruits and vegetables won't
you make you full?
I'm on a dissociated diet and I can offer some anecdotal insight here.
In some days I eat meat and diary. In other days I eat fruits and vegetables only. I also have days where I allow myself to eat whole-grain bread or pasta. The only days in which I don't feel hunger are the days when I eat meat. If I eat for instance pasta, or potatoes, or rice, in 2 hours tops I get hungry again. Of course, if I eat beans or spinach ... these vegetables keep me full longer than rice, but I still get hungry.
So the issue here is that meat and diary get digested slower. Beans and spinach also get digested slower than bread or pasta or refined carbohydrates, while having better nutritional value (because of the extra fiber).
It's really not about the quantity.
Btw, I also eat high-fat pork meat as I really enjoy it. I have no problems with cholesterol or other issues. I think the secret to a healthy life is having a diverse diet + abstaining from preprocessed crap.
The main benefit of low-carb diets for weight loss is that they spontaneously reduce calorie intake by cutting out whole groups of foods (by looking at studies it's been shown that any diet that restricts food choices like this will tend to induce weight loss but is usually unsustainable)
Another benefit is that the low-carb diets provide better satiety. In studies, if people were advised to eat ad libitum, those who had to choose from low-carb foods eventually consumed less calories than those, who could choose from "regular" food.
Yeah calories matter but processed foods seem to be the real culprit. They make it easy to eat too much and get addicted to the fat salt sugar combo that leads to problems.
I hate how grains make me feel so I am not going back. Losing weight is a side effect of having more energy via cutting out food that was toxic for me to be eating. This isn't religion but just empirical testing on my part. If it didn't work I wouldn't do it.
I follow Taubes, Sissons and Robb Wolf approach (paleo in general) because it just works for me and I love the food. I am thinner, stronger and with much better health eating tasty food and doing minimal exercise. I think Guyenet's approach may work too (maybe there is not only one right answer) but I think low-carb is easier to me and I dont see a reason to change it. My life is much better after limiting (almost banning) grains and refined sugar.
I just wish we could see more directly a sense of how little we know about good nutrition.
My favorite example is Vitamin B12, mostly because I learned the story when I reduced my meat consumption to about once a month. So there's this family of massive molecules containing the metal cobalt which we can't make on our own because we're not adapted to eat cobalt, and they're all called "Vitamin B12". It helps in the last step of making the protein building-block called methionine; if you get malnourished in this way your body just basically fills up with "almost finished" methionine which is useless and might even be poisonous. There can also be a slight risk of nerve damage although as I understand it we don't actually understand why the hell that would be.
The biggest cause of malnutrition in this sense is simply being old -- you can't absorb Vitamin B12 so well in the first place because it is huge and weird, and old people have even more trouble either because their gut is slowly dying or because they're infected with H. pylori, which is a safe bacteria more than 80% of the time and might even be important for a well-functioning stomach, but might sometimes cause a chronic tummy-bug.
Okay, so that's the problem, but what do we know about how much of the B12s we need and get? We know very little. The US Recommended Daily Allowance of B12s is 2.4 μg, but the US Daily Value for B12 is 6.0 μg. How much do you get in your food? You get almost none from vegetables, and vegans are basically all ipso facto suffering from B12 deficiency unless they take supplements or eat enriched cereal -- but most of them are quite healthy and see no problems from it. As for vegetarians like (almost-) me, the exact range for milk and eggs to get to this limit is imprecise because the limit itself varies by a factor of 3, so you might need to eat three eggs per day or else ten; so you might need to drink two cups of milk per day or else five, to live up to those numbers. So in theory there are lots of vegetarians also who come in at half or one-third their daily requirement, and never notice anything. Meanwhile there are people over 60 who eat plenty of meat but are starting to feel the effects anyway.
We actually don't even know how well you absorb it. A USDA researcher named Lindsay Allen did a 2011 study where she marked Vitamin B12 in eggs so that she could detect it, and then fed those eggs to 10 people. She found that the body absorbed 50% of a 1.5 μg dosage but only 20% of a 2.6 μg dosage. Let me repeat that. She found that, in absolute value terms, eating more B12 led to less of it being absorbed, 0.75 μg versus 0.5 μg. It's probably not statistically significant with 10 people, but still. We don't even know that eating more leads to you absorbing more of it. (I also wonder whether RDAs are "amount absorbed" while DVs are "amount eaten", as this is pretty much never reported, but I will assume that they aren't crazy and that it's always "amount eaten.")
I wouldn't use the scare-quotes around "science" when talking about nutrition science, as I think there is potential for real research here and I think people do indeed do it -- but it's a lot of work before we have a firm understanding, and most of that work hasn't been done yet, and yet you hear these confident conclusions. I would just like to hear people publish standards in the form, "you might need this much, or that much, we don't really know."
The engineer in me craves error bars. Where are the error bars?
I think that when it comes to diet, you should follow your instinct on how much to consume and listen to your body, while also doing blood analyzes from time to time.
I believe that we all have unique metabolisms and the real "science" is the personal study of how we feel physically correlated with what we have been eating, amount of exercise, lack of tension, etc. I ended up as a vegetarian (with a little fish) because I kept track of how I felt and compared with recently eaten food. I have friends who thrive on high meat diets. We are all different.
Of course statistics dont necessarily translate to the individual. But to further agree with you I would point out a rather nasty (I think) trend in medical science, which is to treat individuals who diverge from the statistical models as defective.
Look up the medical literature for "Cytochrome P-450 defects" for example. What folks are typically talking about here are differences in rates of metabolizing various pharmaceuticals. Some people like are considered defective because we process many medicines very slowly. Personally I think this is great. I take less medicine, and I suspect it may be why constant moderate drinking (alcohol) eventually makes me mildly sick and I have to stop for a while. It's great. Except that it's called a defect by pharmaceutical researchers.... and there's even experimental gene therapy to correct it.
I'd even guess that people who are happy and at peace with what they eat might outlive hardcore perfectionists. Are there any studies about that? (I'm thinking of a parallel to the study where religious people lived longer.)
A lot of people "feel" fine but blood work shows they're insulin resistant, have various deficiencies, or are loaded with cortisol. Going by "feeling" really doesn't work. Also, the evidence against a vegetarian diet is overwhelming.
Also, the evidence against a vegetarian diet is
overwhelming.
If the totality of evidence currently available clearly indicates that vegetarian diets result in premature death, it should be very easy for you to link to a dozen or so clinical studies that have produced such evidence. Please proceed.
There are many vegetarian Buddhists here in Taiwan and their food is sadly well-known for being overly greasy (as to add flavor). It doesn't help that the local Buddhists avoid onion and garlic, two staples in non-vegetarian local food. It's considered normal to eat supplements, but that's of course a recent phenomenon.
I'm not saying it's all bad (I'm mostly vegetarian), but the studies are all over the place as with everything in nutrition :)
There are so many varieties of vegetarian diet the term is a little meaningless in terms of understanding nutrition.
I've been vegetarian for about 20 years, I eat a lot of fresh veg, not much fried stuff, not much processed stuff, try and make sure I mix things up and get some protein. Broadly speaking I think I've got a pretty good diet.
But I also know vegetarian's who are massively overweight, eat crap (and too much of it), drink too much and so on.
As a broad group I suspect vegetarian's eat better but I think that's more likely to be linked to the fact that this is a group of people who have thought about what they eat as much as anything inherent in the lack of meat.
And that would be interesting (and I think they do exist - I'm curious about the poster above saying that they show it's not healthy because my understanding is precisely the opposite), just I think that there are other factors you need to control for to really understand it.
While researching a bit about the interaction between ADHD and food, I stumbled on articles about that kind of diet.
My (real) question is : what do you eat and how do you keep pleasure in eating ? From breakfeast to super, how can you even avoid bread (and cheese), the best thing on Earth ? It seems so impossible to me.
I am not on a paleo diet. Instead I'm on a dissociated diet and I lost 42 pounds since February.
I do not avoid diary products. I do avoid bread, but when I do eat bread, I prefer bread that's made of whole grains. And so I'm making my own bread. In general I follow these 2 rules:
(1) I stopped eating refined carbohydrates or preprocessed crap (entirely, no exceptions ... all the sugar I want comes from fruits)
(2) I never combine food rich in carbohydrates with meat or diary (I eat potatoes for instance, but without meat)
As to your question on how can you give up bread: refined carbohydrates give you a dependence, just like nicotine. The more you consume, the more you crave for more. When you stop eating bread daily, you simply will stop carrying about bread.
I find things that work for every meal and try new recipes. Bread tastes great but I avoid it because if I eat it then I will pay a heavy price. Try the primal blueprint for 60 days and see what happens. I noticed a huge change in 24 hours but my results are not typical.
The Primal Blueprint by Mark Sisson is also great and changed my life. Reading 'Good Calories Bad Calories' now from Gary Taubes (the author of the op) and it is awesome too.
Thanks for the references.
Are they solid science? all I have personally come across about the paleo diet is unconvincing and does not stand up to scrutiny.
"I want to believe" would be my stance.
If you look for more references and science debate, I suggest 'Good Calories Bad Calories' from Taubes. 'The Primal Blueprint' has some references but it is more focused on the practical matter. I can say that it worked very well for me and 2 other friends that tried it.
If you want to go old school you can check out the Hacker's Diet (free online, and recently got an epub version): http://www.fourmilab.ch/hackdiet/
After a lifetime of thinking that diets had to be permanent and results were only possible through hours of exercise this book turned me around. I lost 50 lbs in eight months and haven't looked back.
Good Calories, Bad Calories has over a hundred pages of citations in the back so it's at least well referenced. I have yet to read it though so I can't comment on the quality.
Well Loren Cordain, godfather of "paleo", remains convinced that salt is bad. He claims the chloride does some bad stuff (I forget) and also the sodium screws up potassium and magnesium levels somehow.
I don't there can be much doubt that improper ratios of sodium in the body can be bad. In particular I'd look at the ratio of sodium to potassium. But the same goes the other way too. Being sodium-deficient is really not fun. I know from experience.
Sodium and potassium have a significant number of important roles in the body and they are balanced against eachother. Too much sodium will mess up the potassium functions and vice versa.
Avoiding processed food might be what's keeping you healthier in general. Not because processed food has bad nutrition but because the additives are tricking our bodies. I feel that if you stick to basic ingredients (at least nothing with taste additives) you can pretty much go on cruise control and let your body decide.
Sort of an aside here, but salt and MSG should be used to increase the tastiness of otherwise bland foods, like asparagus, so that what you eat is more in line with what your body needs, rather than what is the most tasty in our post-industrial world. That is how I use salt: reduce starches and refined grains, and increase vegetables, lentils, and the like. Sure I still have some bread and a normal amount of meat (at least by Canadian standards), but I prefer to make healthy foods delicious.
We might also want to think about _why_ some foods taste bland. I feel that I'd never really tasted what a tomato tastes like until I had some at a monastery in Greece.
I was surprised to see tomatoes sitting out at dinner, seemingly to be eaten as-is along with the meal. I bit into one and it had a flavor unlike any tomato I've ever had in the USA. I could finally understand that a tomato is a fruit! It was nicely sweet with no bitterness and no discernible acidity.
In the USA when we ship stuff across the country, gassing it to stop it from ripening, and then gassing it again to cause it to ripen again -- all the while eating things mostly out of season -- it's no wonder that our foods taste bland!
The other part of it is that if your body is used to a high calorie diet with lots of sugar and fat, vegetables are going to taste bad no matter how good they are. And if you're eating healthfully, then even supermarket vegetables will taste reasonably good.
That's true. I remember when I stayed in Japan for a while, initially I found the food underwhelming. It turns out that good 'ol Japanese homecooking isn't designed for the American palate, which is accustomed to lots of sugar, fat, and calories. After a month, though, I loved the food and tasted all sorts of subtle flavors in the vegetables.
Once I came back to America, I found that food here was overwhelming my tastebuds. In particular, I remember trying to drink some Pepsi. It tasted like I was drinking pure sugar (well, I guess that's what it really is). I couldn't even finish it or any other kind of soda. Now I'm able to drink stuff like that again, but that's probably not an improvement. :)
My parents grew tomatoes in their garden every summer here in the US. I've been eating tomatoes like that since I was a child. Sliced, as a side, in the summer, with a little salt and pepper. I only do this when they are homegrown though.
I started eating vegetables without salt many years ago, and once I got used to it, they don't taste bland to me at all. Even the regular grocery store ones. Of course, if you get homegrown organic ones, they are way better - but even the grocery store ones still have a lot of taste, unless your taste is ruined by years of training it that vegetables should taste like salt. I actually hate when more than a trace of salt is added to the vegetable salad - then only thing I can taste is the salt, it overwhelms everything else.
just FYI, in the pre-industrial world of my home town you can still go picking up wild asparagus[1] which are _far_ from bland, I have no idea if those exist in any form where you live but I strongly advice you to try them out if you can.
Asparagus is wonderful for many reasons, but one of them is the range of textures and tastes different cooking methods can impart.
Grilling kicks off charring on the outer skin (not Maillard reactions to my knowledge - no amino acids - but something similar), and gives a wonderful gradient of textures between the skin and the soft, liquid core.
Microwaving (yes, really - NYT had an article about microwaving vegetables a couple of years ago, pointing out it's an excellent way to cook most veg) gives crisp, even spears with no toughness but plenty of crunch and a superb retention of pure flavour.
Frying with garlic is probably the best way to introduce other flavours that will complement the main spear, IMO, and also leans toward the softer texture of grilling.
Boiling has its place too - I avoided it for many years before becoming curious as to why blanching is still used in most top-end restaurants. It's very fast, it produces a softer spear than steam or microwave, if you time a cold water bath right it'll give you a brilliantly green stalk, and it gives nearly as clear a taste as microwaving. Plus, it's a good way to introduce the tiniest bit of salt - which acts as a flavour enhancer.
Even those of my friends who know that the health concerns are bogus have a weird paranoia of MSG. I think it's a general suspicion of any chemical which makes food taste better (which somehow doesn't apply to salt and sugar).
I think part of the problem with MSG is the name. It's hard to convince the general public that something with the name "Monosodium Glutamate" is a naturally occurring substance, let alone one of the more abundant naturally occurring amino acids.
Hell, if we called table salt "Sodium Chloride" all the time, people would probably have a bit of a changed perspective.
Conversely, it winds me up when products boast that they have no artificial ingredients, yet have colours or flavours which are mixtures of natural substances that have little to do with the products that they are being used to imitate.
I think that's the idea behind the "All Natural AC'CENT® Flavor Enhancer" branding-- they don't say "monosodium glutamate" anywhere on the package except the ingredients.
I just call it supersalt. Because it's like salt, but not salty!
Technically, MSG is supposed to be the "extra" taste area they didn't know about/ teach in school. So although it seems salty, it's actually the savory flavor. MSG is found in just about every single food you eat that has that "savory" flavor.
To clarify, since your parent didn't actually misspeak-- There are actually only five main tastes your taste buds can detect. They just aren't organized by location.
To the best of my knowledge, MSG isn't actually found in most sources of umami, but it's an excellent source of that flavour.
Well-known umami-tasting foods include red meat, cheese and other fermented products, and tomatoes. None of these contain MSG directly (tomatoes get their umami from glutamic acid, according to umamiinfo.com). However, MSG can be used to add more umami flavour, which acts as a flavour enhancer.
You're probably right. Did you know that dihydrogen monoxide kills thousands of people every year? That substance has been found in the blood of every terrorist and serial killer in human history. Scary stuff if you put it that way.
One way to look at MSG (the way I look at it) is that it has been shown to stimulate the appetite. As a result of this, people often eat MSG-infused food more than they should. My wife once said that MSG "makes me think this tastes better than it really does".
So, MSG may or may not be bad by itself, but the highly processed empty calories that it hangs out with, definitely bad. Bet you can't eat just one? I don't take that bet anymore, I lose too often.
I think that's exactly what I mean by "paranoia". It's certainly true that MSG makes food taste better than it "really does", and makes you want to eat more-- as do added salt, sugar, or any seasoning for that matter.
For some reason only in MSG does this quality inspire distrust.
I think it's a distinction of scale. It's like the difference between chewing on a cocoa leaf and smoking crack cocaine. They both have an effect, just one is so much more refined in a way that our bodies haven't co-evolved with for thousands of years.
The same holds true for the difference between eating fruit and drinking HCFS soda or the difference between drinking beer and distilled spirits.
One might even liken it the difference between gnawing on a stick of sugar cane and eating ice cream, or licking a rock and eating a salty potato chip :) I still haven't seen the thing that makes MSG especially sinister.
I've got some foggy memories about this from talking to a nutritionist a few years ago. A quick google search brought up an abstract to a study from some time ago.
Indeed, the most important finding concerning MSG showed that motivation to eat recovered more rapidly following a lunchtime meal in which MSG-supplemented soup was served as the first course (compared both with the effect of unsupplemented soup and no preload)
Regardless, MSG is exactly the sort of "industrial edible food-like product" that I'm avoiding for aesthetic reasons, if nothing else.
I have always wondered why so many facets of "institutional health" are promoted as the status quo even with much contradictory evidence or lack of "common sense".
A couple of things that come to mind:
salt
saturated fats
sugars
I know many instances of this problem have to do with monetary interests. But salt? Who gains from low salt intake? Reputation? Or is it something else.
Taube's theory (about cholesterol, but I think it applies here as well) is that it's "where the light is". Things which are measurable are optimized for even if they're pragmatically pointless.
So a study comes along that finds a correlation between sodium intake and cardiovascular disease. Totally possible. The USDA looks at those numbers and says, we're eating Xmg of salt, we should be eating Ymg. They make a recommendation, years go by, and they look at the numbers again and, hey, salt consumption is down to Ymg! Success!
What about mortality? Who knows. That's not their department.
Not to sound like I'm putting on my tin-foil hat, but a lot of money floats around in this space. It's entirely possible for a segment of the food industry to be viewed the same as cigarette companies if extensive studies show that, for example, eating cereal is actually killing you. No company wants that death sentence, pun not intended :-P
TBH my general health has improved after I stopped giving a crap about rules and regulations and just eat when I need to not when I want to. Determining between want and need is the hard bit.
Increased blood osmolarity will lead to an increase in blood volume, period. If you add fluid to a closed system, the pressure of that fluid on its container will increase. However, in most cases, excess solutes should be excreted relatively quickly and blood volume will return to normal.
>If you add fluid to a closed system, the pressure of that fluid on its container will increase.
Does the inverse hold up as well (in regards to the human body)? If people have high blood pressure, if the gave a couple of pints of blood each month, would that do anything to lower the pressure?
Of course it would lower the pressure temporarily, until the body restored blood volume to normal levels. But hypertension is defined medically as a chronic condition.
The harsh reality is that there are so many variables when it comes to diet and nutrition information that formal studies are close to worthless. That is why I find information like the studies Weston Price did [1] interesting. His conclusion was that any society on a whole food local diet was generally healthy and that pre-mature physical degeneration only happened when "primitive" diets were replaced with "modern" diets (i.e. highly processed).
Here's a simple rule. If you could find/grow it in your back yard, eat it. If not don't.
Gary Taubes (author of this article) goes over the evidence on salt restriction in more detail in Good Calorires, Bad Calories, but it is missing some recent studies indicating negative outcomes for salt restriction. I believe Taubes is often wrong (as most people are) when proposing his hypotheses. But he is very good at tearing down wrong hyptoheses.
The important thing to remember is that processed salt, which is devoid of all minerals and trace elements is not the same as good-quality natural sea salt, which does contain the trace elements and minerals and is able to be absorbed by the body more easily. Processed salt actually saps the body's mineral reserves and is very hard on the body. In colder harsher seasons for those living in temperate climates, more (good quality) salt is necessary than for people living in the tropical regions for example. Moreover, practically all general restaurant food has entirely too much processed salt content and will actually age you overnight.
There was an idea in 'Fat Head' where the narrator pokes fun at the idea that we are a species who's evolution has made us so that we crave foods that are actually killing us. It's not proof that we can't crave foods like sugar, fats and salt that might be harmful to us, but I think it sets up a health amount of skepticism towards the idea that our innate cravings are in fact harmful.
"...we are a species who's evolution has made us so that we crave foods that are actually killing us."
"...it sets up a health amount of skepticism towards the idea that our innate cravings are in fact harmful."
It's modern processed food that's harmful.
We evolved to cope with the amount of salt, sugar, carbohydrates etc. that was readily available to our ancestors on a hunter-gatherer diet (we would've reached an evolutionary dead end otherwise if our "innate cravings" were not useful to us in a survival sense) - you would have to do a lot of hunting and gathering to get the amount of salt, sugar, saturated fat etc that a single fast food meal provides - it was relatively rarer so we have cravings to ensure we got enough of them back when they were scarce.
Evolution is a very slow process. Adding syrup to carbonated water, advertising the crap out of it and selling it at huge markup (coca-cola) can happen over the course of a single human's lifespan.
Salt is a very important part of a human's diet and was a major trade item for all of recorded history. Salt has been used as a preservative for meat for as long as I'm aware of. Animals often sit and lick natural salt deposits.
There is a common belief that meat and especially fat are bad for you and cause heart disease, which is the particular idea that Fat Head makes fun of. He reduces his carb and sugar intake and lowers his cholesterol and loses weight.
I quit drinking soda and reduced my sugar intake because it made me feel bad. I sometimes crave sugar after running a lot or when I'm tired and I will occasionally drink a soda, but I usually regret it. Same with candy etc.
I can only speak for myself, but the idea that my natural cravings and the reaction of my body are good indicators of what is healthy has been very successful for me. I currently believe that fat and meat, plus vegetables are very health and I crave all these things. My body is very sugar sensitive and so I avoid it because of how I feel. The guide that my evolutionary tastes are not trying to kill me seems to be a pretty good guide towards finding a healthy diet, and I believe it will serve me better than the National Health Services recommendations have. If you believe that there is good reason that evolution may be guiding you towards something unhealthy, you may be right, but my default answer is the it is correct unless there is a better explanation.
"If you believe that there is good reason that evolution may be guiding you towards something unhealthy..."
I don't think there's any doubt about this. Compared to evolutionary rates, the typical diet in the west has changed at lightning pace from just a few decades ago, meaning our bodies and taste buds are behind the curve. We need willpower and common sense to have a healthy diet, rather than raw survival instincts.
Unfortunately what's driving change in our diet is the demand for companies to serve food with high profit margins and low cost raw materials (e.g. high-fructose corn syrup). Capitalism is great for providing us with cheaper clothes and ever-cheaper computing power, but providing cheaper food means providing crappier food. There's no Moore's Law for food.
I think it was here on HN I read about studies done in remote communities (possibly some remote whaling community) that had recently become westerised, and the diet quickly shifted to one more similar to a typical American diet. Within 5-10 years (or a relatively short time frame, can't remember exactly) obesity and type-II diabetes rates exploded.
Another interesting story was reports from surgeons who operated on injured Afghan fighters from the current conflict. Normally when operating on westerners, you expect a certain amount of yellowish fatty tissue surrounding the major internal organs. This wasn't present on Afghan locals, which surprised the surgeons who were so used to seeing it on western patients and pretty much assumed it was normal up till that point. The difference was down to diet.
I like your comment but you are confusing the issue. Your argument is that processed food is bad for you and cheaper because of production scale and I completely agree. My point is that if I take two meals and put them in front of someone, one with a red steak wrapped in bacon and vegetables and one is a hamburger and fries, I suspect most people will chose the high fat meat and veggies. However, the government has been pushing the food pyramid http://www.nal.usda.gov/fnic/Fpyr/pmap.htm as a school indoctrination program for as long as I can remember. As far as I can tell that hamburger fits right in with your six to 10 servings of bread a day, and they would tell you it's the bacon that is making you fat and giving you heart disease. So yes, cheaper food is worse for you generally speaking but that is about economics, not evolutionary tastes.
Cravings can be trained and influenced by person's knowledge, I think. Example: When I was young (and stupid :) I drunk a lot of cola. I literally craved it, I chain-drunk it whole day. Then I learned what that thing actually is, and then my doctor told me my blood sugar is entering regions where it shouldn't be. I didn't touch the stuff since, and now the mere sight of it disgusts me. I tried to drink it, and I realize I actually hate the taste now. I have no idea how I could enjoy it years ago. Maybe I'm just impressionable, but here it goes.
I still like the sweets, however, even though with my complexion it is best not to overdo them. I guess it has its limits. But if I gave in fully to my cravings in this area, I'd probably have a very serious health problem by now. So trusting "evolutionary tastes" is a dangerous path - unless you put it under strict control of the higher brain, I believe it can seriously harm you.
Indeed. Some processing is good, but a lot of it just makes the food too easy to eat. I would argue that even processing food at home, such as mashing potatoes can be a problem unless you are careful about the portion size - i.e. remember how many potatoes were used to make it.
Our bodies are full of feedback systems that only work in our natural (i.e. pre-civilization, pre-agriculture, hunter-gatherer, nasty, brutish, short) environment. It should be no surprise that our food cravings are among them.
There are other fun examples. One is that our breathing reflex is based on CO2 concentration being too high rather than O2 concentration being too low, even though O2 concentration is more important! Breathe into a closed system with a CO2 scrubber in it and you'll quickly get loopy and then pass out from lack of oxygen (and then die, if nobody disconnects you) all the while feeling fine. Another is that the iris of the eye responds to visible light but protects against more. Looking at the Sun is normally OK (uncomfortable, but tolerable) because the feedback is set up properly, but during the totality of a solar eclipse (which of course occurred back then, but not often enough to matter, apparently) your iris will crank open and let in tons of UV from the Sun's still-visible corona, frying your retina if you look at it.
It makes a great deal of sense that we'd evolve strong cravings for things which are good for us in small quantities but bad for us in large quantities when those things were scarce in the distant past, and death came early by other means for other people, well before a bad long-term diet could kill. That doesn't mean this must be what happened, but given how much humans love sugar, and how rare concentrated sugar would have been for our ancestors, it's no surprise if sugar turns out to be bad for us when consumed in the quantities we really want.
This misinterpretation of what the authors of the study Cochrane should have said, led to the conclusions being re-written to conform to what was actually found:
No offense but this is really an intellectually weak statement because moderation is dependent on what is considered "too much", and here we are looking to redefine just what "too much" really is.
Seriously, almost all of modern food/health science could be reduced down to this simple phrase. Eating too much of "X" is bad for you. No, really? Ya think?
I don't mean to beat this to death, but any kind of statement about moderation presupposes that we already understand how different amount of some substance will effect us. The topic under discussion boils down to "what is too little, what is too much and what is moderation?". You cannot answer that with "just go for moderation" when moderation is precisely what we are trying to define.
I see this kind of thing all the time and it irks me because I see so much agreement with what amounts to a circular statement.
The one study this person mentions by name (and dismisses) is the DASH-Sodium Study.
http://en.wikipedia.org/wiki/DASH_diet#Study_Results
"Like the previous study, it was based on a large sample (412 participants) and was a multi-center, randomized, outpatient feeding study where the subjects were given all their food."
"The DASH-Sodium study found that reductions in sodium intake produced significantly lower systolic and diastolic blood pressures in both the control and DASH diets. Study results indicate that the quantity of dietary sodium in the control diet was twice as powerful in its effect on blood pressure as it was in the DASH diet."
So, positive conclusions (lower salt -> lower blood pressure) in a seemingly well designed study. People were randomized, it was prospective, and people given all their food. So, change one thing and see what happens.
The author here seems to cite other studies to make the opposing case (low salt = bad), but doesn't give exact references. I did a quick google search and found this one: http://www.nytimes.com/2011/05/04/health/research/04salt.htm... But you can already tell it's an inferior study. "It involved only those without high blood pressure at the start, was observational, considered at best suggestive and not conclusive."
So, let's try to compare apples to apples.
He points out that the DASH study didn't conclude anything about death or cardiovascular disease. Yes, that's true. So sure, there's a chance that despite blood pressure reductions a low salt diet could cause problems. But it's not the obvious conclusion. Anyone have any solid studies on this?