What is the evidence in favor of paleo?
I recently came out against paleo in the open thread, and realized that I probably haven’t yet heard the strongest arguments in favor of a paleo diet. So, what are said arguments?
EDIT: Or more generally, why should I eat less carbohydrates and more protein / fat?
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I’m very skeptical of reasoning like “it was like that in ancestral environment so it must be good”. There are at least three reasons that makes me uncomfortable with the reasoning :
Even if we consider evolution to be a perfect optimizer (which it is not), there is a huge difference between “our digestion system is optimized to make the best possible use of food X” and “food X is best possible food for our digestion system”. If you made an algorithm A optimized to transmit data on a noisy channel N, it doesn’t mean the algorithm wouldn’t run better on a less noisy channel C. There may be an algorithm B that work better on the clear channel C than A, but still, A can work better on C than on N.
Evolution doesn’t optimize for the same purpose we do. Evolution doesn’t optimize for us to live long, it has a very low pressure to make us live past ~60, for example.
We have completely different lifestyles and activities than we did during paleolithic. And the optimal diet very likely depends of lifestyle and activities.
That said, what would convince me to do a diet is not a plausible-sounding reasoning, but some evidence of short-term and long-term effects on a sane sample size, with a control group. Something which seems very rare in the diet field, saddly.
Your grounds for skepticism match the heuristic that Anders Sandberg and Nick Bostrom propose in The wisdom of nature quite closely. They propose this heuristic to evaluate interventions to enhance humans, but it’s clear that it has much broader applicability. Here’s the relevant excerpt:
You should start the excerpt earlier to explain what is meant by EOC:
Gwern discusses these on his drug heuristics page.
Evolution doesn’t stop. We have continued to evolve, adapting to new environments, including foods.
But it’s really slow, some new traits are lactas in adult age, gluten tolerance, but rerouting your entire metabolism is something altogether. Besides optimising from evolutions point of view (e.i. maximise reproduction) is not the same as optimising from most peoples point of view (e.g. living longer, being healthy past middle age).
Most living people don’t optimise for that either. If they did, more would practice calorie restriction.
I’ve yet to see any evidence on the effects of calorie restriction on humans. Mice are quite different from us, and all evidence on calorie restriction I’ve seen was done on mice.
Also, there is no just how long you live, but also life quality. We know the brain is a massive consumer of calories. We know that when people are even in light hypoglycemia, their reflexes and cognitive abilities go down. I never saw any study on the effects of calorie restriction to attention, reflexes and cognitive abilities.
Some human research is listed here.
There are plenty of studies on that—e.g. start here.
Evidence on humans can be found through here, and extensive discussion on evidence in macaques can be found here (although I recommend reading the whole discussion and/or the study; the root comments are less informed than the leaf comments).
I believe there have been encouraging experimental results in other mammals, including primates, as well as human trials with surrogate endpoints. I also recall seeing a least one ongoing prospective cohort study with promising interim results. Will google and append links when I get a moment.
I would expect mild ketosis to compensate for hypoglycemia, but cognitive effects are of concern to me as well. Anecdotally, while practicing intermittent fasting regularly I did not appear to suffer any cognitive impairment.
I do feel (but yes, that’s error-prone) that I’ve lower concentration/thinking ability when I’m late for a meal.
Also, my parents (both retired teachers, one at uni the other in secondary school) both noticed that pupils/students were less focused and more error-prone in the hour just before lunch, and AFAIK (but I’ve no link right now to point at) this was backed by more formal studies than just “personal experience”.
There is also a certified increase of rate of car accidents in Muslim countries during the Ramadan month, due to lower attention/reflex speed when people are doing Ramadan, but AFAIK it’s unsure how much is because of hypoglycemia and how much is because of dehydration.
Edit : for my own personal experience, it may also be because I’m on the skinny part of the spectrum, I weight ~55kg for 170cm, so I get hypoglycemia quite fast if I don’t feed enough or regularly, it may very well be different for people who have more reserves than I do.
Being late for a meal is very different than restricting calories. If you eat a meal at the same time every day, your body gets in the habit of wanting to digest food at that point in the day. More blood re-routed to digestive system, less blood to the brain --> lower concentration/thinking ability before meal. Note I am partially pulling this out of my ass.
I feel better when coming back from lunch, so it’s not the “re-routing blood to the digestive system”. But it could be something with sugar level management, yes, my body expecting to be fed at 1pm, so not taking the expense to start using stocks to provide me with sugar when we are near that time, instead waiting for the coming meal, or something like that.
Anyway, I more wanted to say that diet/calories issues aren’t simple, and that “rodents live 20% longer when on calorie restriction in a lab” is just weak evidence that it would be good for us to do so. There are many aspects to consider (differences between men and rodents, effects on intellectual abilities or overall well-being, immune system strength, capacity to recover in case of disease/wound, effects on different ages, sex or corpulence, …) and studies that evaluate all of that are lacking.
Maybe calorie restriction is worth it, but there is just not enough evidence to tell. Saying “Most living people don’t optimise for that either. If they did, more would practice calorie restriction.” seems to me broad overconfidence.
Interestingly, the calorie restriction effect may just be because the mice used were overweight. article
Ironically, given the Western diet, even if that is ‘all’ CR is, it may still be a good idea and life-extending.
In sensible CR experiments (which date back to the 1950s) the control mice are calorie restricted too, precisely in order to rule this possibility out.
Discussed here; timtyler’s aware of such results and believes the evidence still points towards CR (which is also my opinion).
What about the Okinawans?
What about them? They eat more and differently these days, and accordingly, Okinawa’s life expectancy has fallen.
I was thinking about the pre-WWII Okinawans. Anyway, isn’t what you mention further evidence that CR works, even below the not-morbidly-obese line?
It could be, yes. One question I have here is what is ‘morbidly obese’? Is it like IQ, where it’s essentially a relative ranking (the top fifth is the fattest and defined as morbidly obese), or do we have a clear bright line from biology where a certain weight is the crossing point between good and bad? If it is the former, then for all we know, Okinawans who were eating their fill were still above the bright line even though they look thin and fit from a contemporary American viewpoint.
Yes. My grandmother seems to not give a damn about how much longer she’s going to live, only about how much Fun (which in her case essentially means food and cigarettes) she has every day before dying. And she has nearly explicitly admitted to that. (And no, I’m not just talking about the fact that she eats and smokes too much.)
From casual observation, paleo and intermittent fasting are the only diets that some people seem to like being on, as distinct from being burdens that some people think are worth the trouble.
That doesn’t logically imply that the diet is good for people. People enjoy a diet of sweets, too.
I tend to assume that things people hate are bad for them. CR may be an exception, but it’s plausible that evolution would usually select for warnings that one is hurting oneself.
People tend to like food that is harmful. And they tend to dislike diets that are potentially useful: most people fail to diet through failure of will, i.e. because the diet is not fun. So the evolutionary heuristic seems not to hold for food.
There are different theories why people like harmful food, but all of them try to explain the fact that they do like it. E.g., it is a purposely designed superstimulus due to competition between food sellers. Or, people evolved to want energy rich food that was rare in the ancestral environment, and when it is plentiful they actually overeat. Etc.
I do know vegans who like being vegan.
I don’t have anywhere near enough domain knowledge about the human body to (correctly) evaluate the arguments for and against particular diets, so I figured I’d just run an experiment and see what happened.
This is what happened.
So, you started going to the gym a lot and you started measuring your weight daily and and you lost weight and got healthier. (And also happened to change your diet.)
That’s not really an experiment with Paleo. Not unless you’d already been going to the gym like that and paying that much attention to what you ate and how much you weighed.
Edit: I suppose that the “when I started” statement could be read two ways, one of which would imply that you already worked out that hard (6 days per week) prior to paleo. Though it seems odd you’d be able to do so and still be able to lose 20% of your bodyweight in fat, so I’ll assume for now that’s not what it was.
You aren’t interpreting that sentence correctly. Before and after starting the diet, I was exercising approximately the same amount. Although it is possible that merely increasing the frequency of recording my weight had a (round-about) causal effect on my weight-loss, the magnitude of the effect doesn’t seem very likely.
Measuring weight does lead to weight loss- but mostly through unconscious changes in diet and activity level. If you’re consciously changing your diet at the same time, it should wipe out those effects.
Ah. Well then that is a signficant change. How long had you been working out at that level prior to starting the diet?
Like, could you have been in the (1-2 mo.) muscle building phase right before starting paleo, then the weight loss phase kicked in just as you started it? Or had you been working out for years at that level then decided to start paleo?
Since I don’t like the commenting options on your blog, I’m going to respond here to your melatonin experiment. Comparing two periods is statistically dangerous because so many other details might have changed between them. It is good that you are going to do two more periods, but I think you should do many trials of shorter periods, say, one week each. The drawback is that sleep has cumulative aspects.
Gwern suggests that you try smaller doses. I suggest that you try much smaller doses: 0.3mg. Or maybe cut those up.
Is there anything I can (easily) do to fix this?
The reason I am doing longish trial periods is to test the “addiction/withdrawal objection” to melatonin use. Although, now that you mention it, week long periods should work for this. Also, I was thinking about using the interquartile range to eliminate the outliers from each month for the final analysis. Do you think that would be an appropriate technique?
Yeah, I was planning on trying 3mg, 2mg, and 1mg. Based on your and Gwern’s feedback, I’m probably going to end up testing 3mg, 1mg, and 0.5mg instead.
You can probably turn on “anonymous” commenting, meaning without registration.
What is the limit on doing experiments? I got the impression was that if the next 2 month cycle showed an advantage to melatonin, you were going to take it regularly. But if you plan on doing month long experiments for the next two years, your will avoid my complaint, though I think you would be better off doing shorter experiments.
You don’t need to worry about tolerance until after you have established that the drug works in the short term, so if you can save time by not worrying about it, you should. If you decide you want to use it long term, you should do month long experiments at that point. Note that you have not yet done a withdrawal experiment, though you have done something of a tolerance experiment.
Yes, the interquartile range is a great metric. You should compute it. But you should also compute metrics that are sensitive to outliers. Improving outliers may well be more valuable than improving typical values.
You are anchoring on the doses available in stores. Clinical studies often use 0.01mg. Given what is easily available, I suggest 0.15, 0.6, and 3, an approximate geometric progression. If you can find something smaller, use it and tell me where you found it.
What was your diet like before paleo? Were you cutting out grains, fruit, or simple sugar?
Burritos, sandwiches, pasta, salads, chicken, etc… Affirmative; I cut out grains completely and significantly diminished my sugar intake. I still eat fruit, but less than before.
Well I was really trying to figure out which of these is the important thing to cut out (or if they all are important). I already have low sugar intake but moderate starch intake. I want to figure out whether there would be advantages to cutting down on starch or if eliminating simple sugars already gives me most of the benefits.
ETA: Also, thanks a lot for sharing your data with us! That was an interesting post to read.
The data I collected can’t really unambiguously answer this question; subjectively, my ‘mind-fog’ seems to be most sensitive to the ingestion of simple sugars, so I think that is where the greatest bang-for-the buck lies.
In most cases, I’m really not intelligent/knowledgeable enough to make good decisions based primarily on scientific theory. On the other hand, I am fairly conscientious and very patient, so I can get by to some extent by letting the world do the thinking for me (via cheap experimental results). I’m glad that you obtained some amount of value from it.
I think part of the problem is that the question being asked varies. It matters what your aims are, (weight loss, general health, etc.) and what you’re comparing it to. People tend to conflate:
For aim X, is Paleo better than the generic unstructured diet I’ve had up to this point? Probably yes.
For aim X, Is paleo better than a calorie and nutrient controlled diet based on all the available evidence? Probably not.
And what you mean by supporting it.
Is the paleo ‘philosophy’ that you should eat like in the ancestral environment always going to be best? No.
Is “eat more meat and vegetables and less refinied carbohydrates” a useful guideline for most people? Yes.
Losing bone mass is one reason I don’t adopt, besides weight loss in general.
It looks as though some people are healthier if they eat some grains. One of my friends has even found that his digestion doesn’t work well unless he eats a good bit of wheat. He hasn’t experimented with other grains that include gluten. He’s got a couple of relatives who show the same pattern.
I believe it’s important to do your own experiments.
When I ask this question I am usually referred to Gary Taubes. Also see Wikipedia. I don’t have time to evaluate the evidence, but I’m pretty skeptical of nutrition science in general.
Edit: Eliezer has spent a few years doing the only thing you can do: try a bunch of diets on yourself and measure the results.
Obviously, the reason I tried and am trying multiple diets is that the experimental result is always that nothing actually works. Except that the Shangri-La diet worked for twenty pounds and then mysteriously stopped doing anything (i.e., abrupt cessation of the diet did not result in any significant change in weight trends) and Seth Roberts couldn’t get it working again. Paleo was among the diets tried, and it didn’t result in any weight loss or other detectable differences. Non-US-approved, powerful, dangerous drugs like clenbuterol, which are supposed to cause weight loss on the order of a pound a day, produced standard side effects but no weight loss in me.
I figure that metabolisms vary at least 10% as much as minds, which is a HUGE amount of variance. It actually points up something I may post about at some point, which is that statistical science itself is often a dead end—you can publish paper after paper after paper about effects that show up in 60% of the population—but you don’t know what separates the 60% from the 40% - and still have no real grasp on the phenomenon and no real ability to manipulate it.
I’d be very interested in such a post.
Have any of the diets you’ve tried produced changes (energy level, for example) for the better or the worse even if they haven’t affected your weight?
Not yet.
Have you posted something about this? I think it’s an important point, too little appreciated on LessWrong.
ETA: I see that I asked the same at the time. I guess that means the answer is “no”.
That may be understating it. Have you come across the book “Biochemical Individuality”? First published in 1956, it catalogues the at times surprisingly large amount of variation among healthy individuals of even such gross physiology as the relative sizes and positioning of the organs. It appears to have been rediscovered in the 90s, but primarily by the less scientific end of the nutrition advice industry. I do not know if there has yet been any reliable work done on the implications of individual uniqueness for, well, just about the whole of medicine, nutrition, and the life and social sciences in general.
Just curious—have you tried drinking cold (around 2 degrees centigrade) water frequently throughout the day (about 500ml per hour)? And drinking about a liter of cold water after waking? Eating you first meal soon after waking may also be advisable.
Your sleep will most likely be disturbed with visits to the toilet, but doing so may increase your resting metabolism. The logic goes that with all that cold water intake, you’ll always be hydrated, and your body must maintain a faster metabolism in order to keep your temperature at equilibrium. The water also makes you feel full more easily, helping to better control desired calorie intake.
It only takes 35 kilocalories to warm one litre of water from 2 °C to 37 °C.
Thanks—that’s quite useful.
I don’t think this is necessarily a good thing.
Updated. Thank you!
E.g., the vast majority of heuristics and biases research. Including many of the researchers you cite, Eliezer.
Michael Rae—Aubrey de Grey’s co-author and the most knowledgeable person about matters of nutrition and supplementation that I know—doesn’t have a high pinion of Gary Taubes. Most of his remarks are spread over several messages on the Calorie Restriction Society mailing list; here’s a representative sample:
Well, in my case I’ve found that The Hacker’s Diet pretty much works for me: the number of calories I get seems to be way more important than where I get them from (provided I get them from something reasonable, as opposed to 2000 kcal’s worth of Coke per day or something like that).
Good calories, bad calories is a good read and it makes a rather compelling argument for limiting carb consumption; however, mainstream nutrition science does not unanimously agree with this view. Hard to say who’s right.
Indeed, it’s sad (from my armchair-observer perspective...) that something as important as nutrition science seems unable to say something conclusive about low-carb vs high-carb diets.
I have no weight problems, but low-carb seemed to correlate somewhat with loosing weight; I can’t say I’m convinced though. I just make sure to excercise so much that I don’t have to worry too much about dietary details. After all, physical excercise is as much a ‘paleo’ thing as the diet.
A search through the NIH site does not seem to show a single reliable study on the subject...
The most obvious, and significant, argument in favor of paleo is that it tends to make it more difficult to overeat or maintain a lot of weight (i.e., it’s acts as a fail-safe against akrasia). Imagine if you only had nuts, fruits, and vegetables to snack on and for anything else you had to cook a meal.
A better diet would be to push your eating window to 2-3pm to 10pm (intermittent fasting), and only eat low calorie things which you’ve cooked (and make sure you don’t buy anything that can be eaten without being cooked).
Basically, from the research I’ve read, akrasia is the most significant factor in maintaining a healthy weight; anything you can do to force or impel your future self to commit to your non-akrasiac desires is a good idea.
Nuts are a high-calorie, high-fat, low-sateity food.
You’re just sharing the fact that nuts are a high-calorie, high-fat, low-sateity food and not making any specific point, right?
Well, I was pointing out that it seems weird to group nuts in with fruits and vegetables, especially given the previous argument that paleo “tends to make it more difficult to overeat or maintain a lot of weight” and “acts as a fail-safe against akrasia”.
EDIT: In particular, fruits and vegetables are low-calorie, low-fat, high-sateity foods.
Consider the typical American diet and what they snack on and compare it to eating nuts; I’d be amazed if it didn’t tend to make it more difficult for those people to get the same amount of calories. I wonder if you’ve had the kinds of nuts paleo dieters eat. They’re unsalted and uncooked walnuts, almonds, or pecans (typically almonds) -- not exactly a superstimulus.
And remember, you need 24 almonds to get ~128 calories.
You’re right, I was imagining peanuts, which are probably much worse.
You must be thinking of a different kind of fruit than I am. I could easily get half my daily calories from apples and oranges. Not to mention bananas or watermelons, which are basically fruit-shaped sugar water. I have to stop myself from doing it, like with chocolate or ice cream.
I’ve totally pigged out on a ~2000 Calorie bag of trail mix before.
Nuts are very energy-dense, so I don’t think they belong in there at all. OTOH, almost exclusively keeping in my apartment foot that needs cooking before eating, or is bulky but not very energy-dense (e.g. apples), is what I usually do when I’m trying to lose weight.
I believe you’ve confused my description of the paleo diet with me advocating for the paleo diet (I am supporting an aspect of the paleo diet, but I then go on to say “a better diet...”).
And although nuts are calorific, personally I have a hard time eating more than 10-20 almonds in a day because they’re simply not that compelling of a snack (I’m not dainty either), but that’s not to say there aren’t better alternatives for a snack
I hit satiety pretty easily with nuts, but I get the impression I’m not typical.
Snacking generally leads to drastically underestimating calories consumed. I’ve found eating 3 big meals in an 8 hour window to be best for me.
Isn’t that what siodine suggested? (Or were you agreeing with him.)
Agreeing. Just adding to the idea.
I have a related diet question on portion size; I guess I’ll ask here rather than the open thread or “stupid questions” thread. Is spreading out your carb intake over the course of the day as good as eating fewer carbs?
If the problem comes from glycemic load (spikes in blood sugar & insulin levels), then it seems like it should be. Instead of eating a big slice of pie in the afternoon, I could have half of the slice then and half at night. Or, even better, a bite of pie every 20 minutes. Then my body wouldn’t be overwhelmed by a huge burst of pie all at once; the constant snacking would mimic the slow-release pattern of low glycemic index foods.
I’d also suggest only eating high glycemic foods after buffering them with fat, protein, and fiber. This concept is sometimes referred to as “dessert”.
Tragically, there is no way under this regime to eat satisfying amounts of risotto.
Hunter-gatherers eating traditional diets had very low rates of the modern “diseases of civilization” including cancer, heart disease and diabetes. When, however, hunter-gatherers switch to eating modern diets they start getting these diseases at high rates. (Of course this correlation doesn’t prove causation, but still...) Also, anthropological evidence from bones show that populations usually became less healthy after adopting agriculture.
Although hunter-gatherers had lower life expediencies than we do, this was mostly due to them dying of stuff (murder, infections, viruses) that doesn’t significantly reduce the life expectancy of Americans. The paleo lifestyle tries to combine the health virtues of modern day and paleolithic man.
I look at paleo as providing Bayesian priors for the health value of different foods. If food X was eaten for a million years by my ancestors whereas food Y was eaten for less than 20,000 years then my prior belief is that food X is probably healthier than food Y. This seems to be the implicit approach taken in the Perfect Health Diet. The value of paleo priors is inversely proportional to the strength of nutrition science.
Forgive me for not having citations to backup these arguments. They are based on my readings of the secondary paleo literature.
I am particularly interested in the following:
Could you at least point me to somewhere (doesn’t have to be a scientific paper) that supports it?
A bit of it is here:
http://www.marksdailyapple.com/life-expectancy-hunter-gatherer/#axzz24p8ZdZs
Here is a good place to ask questions of paleo-knowledgeable people: http://paleohacks.com
This analysis does not mention cancer, and cancer’s identification as a “modern disease” is greatly confounded by the fact that civilization has brought both increases in lifespan (revealing cancer; breast cancer rates in women are far higher above age 60 than below) and great increases in the ability to detect cancer (and thus link deaths to it). An excellent discussion of these issues is found in Siddhartha Mukherjee’s Cancer, the Emperor of All Maladies.
You stated that when “hunter-gatherers switch to eating modern diets they start getting these diseases at high rates.” What evidence is there for this claim in particular for cancer?
The modern “diseases of civilization” have only been really widespread for a century or so, whereas people have been eating grains for about ten thousand years.
I switched from vegetarian to paleo based on Food and Western Disease, which had the best recommendations I could find at the time. I will take Dr. Linderberg’s recommendations as what “paleo” means. Oversimplifying:
Yay: Lean meat, fish, veggies, root vegetables, fruit, some nuts. Drink water.
Boo: Grains, dairy, refined fats, sugar, beans.
The primary argument in favor of the ‘yay’ foods is nutrient density: you get a lot of micronutrients (and protein) per calorie. For instance, you want to consume about 100mg of calcium per MJ of energy you consume. Spinach has 1517mg calcium per MJ of energy. In general, vegetable have lots of micronutrients and not very many calories, so they have lots and lots of micronutrients per calorie.
There are two main arguments levied against ‘boo’ foods. First is that they tend to have low nutrient density. Bread (whole grain) only has 60mg of calcium per MJ of energy. Second, they contain antinutrients, ie. chemicals that bind to micronutrients so we can’t absorb them. Phytic acid is an example of an antinutrient. Nuts also contain phytic acid, which is why you’ll notice a recommendation against eating a lot of them.
The second approach is to copy examine.com’s answer, which deals specifically with weight loss, as opposed to general healthy eating.
> Many diets, both fad and more long-term diets, do work. This is mainly because they reduce calories. > When people switch to a paleo-lithic (hunter-gatherer diet), the foods they switch to are naturally more filling (higher protein, fiber, water content) or have less calories for the size of the food eaten (due to water content; a pound of broccoli has less calories than a pound of grains). > When people switch to a ketosis diet (very low carb), the higher fat and protein levels naturally provide satiety and fill people up. Also, there is some evidence that obese people have a maladapted response to serotonin (of which carbohydrates aid in the synthesis of) and thus omitting carbohydrates omits cravings. People lose weight on a ketosis diet because they eat less on a day to day basis, and avoid large binges caused from carbohydrate cravings. > Diets that manipulate fasting (Intermittent Fasting, Alternate Day Fasting) may have some benefits on the ‘calories out’ side of things as prolonged fasting might increase heat expenditure, but the most significant means for weight loss here is that you control eating. It is much harder to overeat in 8 hours than it is in 16.
These are the arguments that have convinced me—first to do paleo, and then to completely abandon it and eat soylent. There’s also evidence that when populations switched from ancestral to western diets, their health declined. I think this is interesting evidence, and gives us a reason to test ancestral diets. I’m not aware of enough sufficiently good testing to make particularly good arguments for any diet.
I eat paleo whenever I can’t have soylent. This means “whatever Lindeberg said,” (outlined above). This is not antagonistic to carbohydrates. In fact, Lindeberg’s best know for studying the Kitavans, an ancestral population that gets 69% of its calories from carbs. If paleo means “whatever Lindeberg said,” then I’ve presented the strongest arguments from his book. This set of foods tends to be high in nutrients, low in energy, and devoid of antinutrients, so we get the nutrition we want in not too many calories.
However, if “paleo” means “replace carbohydrates with protein/fat,” I can’t help you. I no longer frequent the paleosphere and don’t care which definitions you map to which diets. I’ve presented you with the strongest arguments I know for the diet I associate with “paleo”. Sorry if that’s not the diet you were looking for.
If paleo/primal advocates were strong rationalists, they would state the basic premise of the diet as follows:
“In the absence of evidence, the safest bet is to go with an ancestral diet.”
And I think it is difficult to argue with that. When the evidence is mixed on a topic, it seems natural to default to tradition. In general I think paleo/primal dieters consider non-ancestral foods guilty until proven innocent...as in, you would have to present them evidence that a non-ancestral food was harmless and healthy before they started eating it. Most people are asking “Why shouldn’t I eat X”, but within the paleo/primal philosophy, the burden of proof rests on the advocates of novel foods, since they are the one who deviate from the ancestral default. If you want to debate what exactly the ancestral default was, that is an entirely different can of worms...but it is easy to say which foods are certainly not ancestral.
By the way, carbohydrates are not criticized by the paleo movement. You’re thinking of Atkins. Fruits and tubers were part of our ancestral diet, and they are rich carbohydrate sources. They are encouraged in moderation.
The paleo criticism is that the modern diet’s primary source of calories is now grain, which was scarce in the ancestral environment. More dedicated paleo folks will also attack milk, legumes, and nightshade vegetables (in that order) but really the majority of complaints are directed at grain. Before agriculture, no one really ever ate it. After agriculture, the population boomed and people didn’t really have any better options other than grain. Now grain has been ingrained into our culture (pun intended) even though we have the resources to avoid it.
Anyway, there are three compelling pieces of evidence against grain: Lectin, Gluten, and Phytic Acid
1) Grain contains large amounts of phytic acid. Nuts contain more than wheat, but we don’t typically eat that many nuts per day. Chemists would call it a chelator, something that binds with ions. Dietitians would call it an anti-nutrient...it essentially stops your body from absorbing Zn, Fe, Ca, and Mg. Ruminants and grain-eating animals have evolved mechanisms to break it down, but humans have not.
2) Lectin is a natural pesticide which irritates gut linings. Over time, it causes leptin resistance...which contributes to unhealthy fat storage patterns and other metabolic disorders like diabetes.
3) While the gluten free craze is a bit out of hand, there is increasing evidence for a gluten sensitivity spectrum. Not everyone is a celiac, but a substantial proportion of the population experiences some amount of gut inflammation via gluten.
Add to these three things the notion that grains make it easy to consume large numbers of calories and can cause sudden spikes in insulin, and I think you have a pretty good idea of why the paleo/primal diet discourages extensive grain consumption. It’s really more about toxin and anti-nutrient avoidance than it is about carbohydrate vs fat as a calorie source—although it is generally agreed in these circles that modern diets are a bit carb heavy.
I don’t think you mean “tradition” in the usual sense here, given that the paleo diet is a (putatively) scientific reconstruction rather than a traditional practice (i.e. one handed down through generations).
Here are some reasons why people might be better off eating less carbohydrates & more fat or protein:
*http://www.ncbi.nlm.nih.gov/pubmed/15148063
In addition, the low-carbohydrate group lost less lean body mass:
*http://www.ncbi.nlm.nih.gov/pubmed/18635428
The patients on the low-carb diet lost more weight & better improved HDL:
*http://www.ncbi.nlm.nih.gov/pubmed/20679559
They also saw greater improvement in HDL (“good”) cholesterol in the low-carb group:
They also mention another reason that LDL increases in the low-carb group may not increase cardiovascular risk:
*http://www.ncbi.nlm.nih.gov/pubmed/12761365
Again, the low-carb diet better increased HDL: +18.2 for the low-carb group, +3.1 for the conventional group (P=0.04).
It also better decreased Triglycerides: −28.1 for the low-carb group, +1.4 for the conventional group (P=0.04).
Note: This is a copy of a comment I posted months ago in another diet thread.
We may soon be getting some real data. From Gary Taubes’ blog: http://garytaubes.com/2012/01/updates-for-2012/
“Among the projects we have in the works is a non-profit, the Nutrition Science Initiative (NuSI), to raise money for the kind of research we think is necessary to clarify the relationship between dietary nutrients, obesity. diabetes and their related chronic diseases. We have a specific plan of research to pursue (or rather to fund so that established, unbiased researchers can then do the studies) and have already recruited a world class scientific advisory board and executive board.”
According to a later post: “We’ll say much more about this when we formally and publicly launch NuSI in early September. The ultimate goal is to create what would ideally become a kind of Manhattan Project of Nutrition: a concerted, directed, well-funded research effort composed of the best scientists in the field — all independent and suitably skeptical — working together to generate the evidence necessary to put to rest, one way or the other, all the major and many of the minor controversies in nutrition research.”
Many of the diets that appear to “work” (meaning reducing fat and supporting lean muscle mass) restrict carbohydrates, especially forms of carbohydrates that are rapidly metabolized. In my view, this commonality is much more interesting than the theoretical arguments for one diet versus another.
Anecdata: I have lost over 30 pounds since switching to a vaguely paleo (but really more carb avoiding) styles of eating last december. I track my weight daily, and cheat on saturdays, except a couple weeks ago when I cheated for the whole of Gencon. Very reliably, I gain weight after Saturdays, and gained 9 pounds over the course of Gencon. I tend to lose weight after days that I do not eat carbs on, and my lowest weight for a given week is almost always on Saturday morning. I do not track calories at all.
IIRC most weight gain/loss over very short periods of time (e.g. one or two days) is usually due to water weight. So if you gain weight only on one day of the week, it’s probably just water.
Anecdotal: the weight lifters / body builders I know say less carbs and more protein is helpful to their goals, and they say that paleo and/or Atkins is something to cycle through and not adopt as a lifetime diet. Three months of less carbs and more protein, three months of something else, three months of etc.,then if needed or desired three months back to less carbs and more protein. That time limit is something I see lacking in most discussions on the topic, and if I hadn’t been told directly I wouldn’t have known either.
Anecdotal: met a guy once who said he’d lost a large amount of fat quickly and kept it off using Atkins. He had adopted it as a lifetime diet.
Anecdotal: if I eat somewhat less bready stuff, I’ve got more pep in my step.
These anecdotal facts are large-percentage true and small-percentage applicable to anyone else. Look ma, I’m learning to speak Bayesian!
Modern highly processed food is optimized to our sense of taste, to the extent that they can be called superstimuli. They are also correspondingly unhealthier, on many metrics. (I suppose this is the part in contention… I don’t have any sources for this claim, sorry.)
The paleo diet, as well as the Atkins diet and other diets, inadvertently ‘works’ because highly processed foods tend to be carb-based (crackers, cookies, chips, sugary cereals, sugary yogurts, sugary soft drinks, sugary baked goods), and are thus excluded.
Right of the top of my head. Not all of them are scientific rigorous, just evidence that points against carbs.
A high carb diet was only introduced around 10k years ago with the invention of agriculture. As hunter/gatherers the diet was mostly hunted animals(protein/fat) and some occasional carbs from gathered fruits. So the human body is mostly adapted to protein/fat.
Methabolic pathways. Carbs once inside the body are broken down into sugar, which hasn’t much nutritional value other than providing energy and the excess is converted into fat. Proteins can be used to make energy too, but obviously are much more nutritious. Fat and protein is digested with a different methabolic pathway that will also assist in burning body fat. But all fat burning stops once you ingested carbs and the blood sugar raises which makes it hard to lose body fat. There is evidence that your muscles can also function more efficiently in fat burning mode, but for this transition to occur you have to get rid of all the carbs first(including the glycogen stored in your muscles) and retrain your metabolism(may take weeks).
you can survive on a diet without carbs but you can’t survive without proteins and fat(there are essential fats that are needed by the body).
Certain kinds of problems can be solved by a low carb diet(at least one kind of epilepsy), suggesting that certain adaptations are recent.
Lots of people develop health problems(overweight, diabetes) that has to do with an excess of carbs. Also there is a general trend in these problems over the years as people are consuming more and more high carb diet(aka junk food).
Carbs are appetite stimulants, causing overeating.
It’s easy to overeat in carb in general, they literally just melt inside your mouth, whereas with meat you have to do real work(chewing and digesting). Try eating just meat/fat for one week, I found this to be almost impossible.
From my personal experience it is very hard to keep a low carb diet because carbs are just so delicious, try staying off them for just one week and you will understand.
Just one link that I found right now: 60 Minutes explains the latest science behind the conclusion that excess sugar has measurable toxicity, the liver creates fats from excess sugar then linked to blood clots and heart disease, and cancer rates are linked to excess sugar, and reward regions make can sugar addictive
Many modern H-G cultures are the opposite, with the majority of calories coming from fruit or other mostly-carbo plants. It’s less clear what prehistoric people ate (except that they had widely different diets at different times and places; there’s surely no single “paleo diet”). But at least many non-HG historical people who eat or ate a “traditional” diet which is mostly carbohydrates (with rice, corn, or maize as staple foods), where only the rich ate meat often, had a much lower incidence of modern metabolism-related disease.
If only it were that simple. But “what causes obesity or type 2 diabetes” is far from a settled question. Many people believe excess (refined) carbs are partly or mostly to blame, but it’s not quite clearcut.
Everything that stimulates the appetite potentially causes overeating. All types of food, incl. protein- or fat-rich food, can be stimulating. Different people have different tastes too.
Well, people used to a paleo-like diet may love meat and find it “almost impossible” (i.e. not fun) to eat lots of carbs. What people like has to do with what they’re used to, what diet they were raised with, how food is prepared and spiced, etc. What people like is not in any case an indicator of what diet is good or bad for them.
The evidence points strongly into that direction.
Carbs are Orexigenic.
Sorry, you are attacking a straw-man here. What I was saying is that it is much easier from a physiological point of view to digest carbs than protein and fat. This is not a matter of taste.
Cite please? That’s what this post asked for.
True, but there are other ways for food to induce overeating. For instance, salty food makes you drink more, and you may be drinking calorific beverages. Some theories hold that food becomes associated with reward value, making people eat more of it over time, regardless of its direct affect on appetite. Fat is calorie-dense, so it’s easier to eat more calories of it before feeling sated than with carbs. Food may modify the onset of satiety by various mechanisms. Etc etc.
Also, not all carbs are created equal and we should really be saying things like “sweet-tasting carbs are orexigenic’.
All of this is intended to support my point that the situation may be more complex than “carbs are orexigenic, which causes overeating, which causes overweight and other metabolic disorders”.
Simple sugars are absorbed more quickly into the bloodstream than any other type of calorie source. Is that your intended measure of being physiologically easier to digest? If so, why does this measure matter?
Eat 1000 Calories in the form of bread, then eat 1000 Calories in the form of meat. Do you agree that it is much easier and faster to chew/digest the bread?
You’re not answering my questions. What do you mean when you say one is “easier” to digest than the other? And how does that measure affect eating behavior?
The 60 minutes and associated talk (“Sugar: The Bitter Truth”) makes many misleading claims, chief among them the one about sugar toxicity. See e.g. http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-about-fructose-alarmism/.
I’m not a biologist, but my friends who do bio research say that the blog post I linked to reflects their understanding of biology and the 60 minutes does not.