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Good Nutrition: Myths and Facts

Editing Note: This post and the previous post originally were one long article.


In my previous post I explained why nutrition information has a role in the non-diet approach – not as a rule, but as information. But with all the contradictory nutrition advice out there, is there really such a thing as “good nutrition”? There is not one single nutrition principle that isn’t contested by someone somewhere. Doesn’t this mean that there are no reliable facts about nutrition, and everything is subject to reversal?

Actually, no, though it can feel that way at times. While many details of nutrition are speculative, some principles are backed by voluminous research. So how do you separate proven facts from tentative theories presented as facts, or outright misinformation?

Identifying True Nutrition Facts

Misinformation runs rampant in nutrition more than any of field of science. There is so much contradictory advice that most people throw up their hands and decide no one knows anything.

But think about it. Is it really possible that we know enough physics to put a man on the Moon, and we know enough human biology to perform successful brain surgery, and yet we don’t know one reliable fact about nutrition – not even something as basic as whether meat is good for us? Does that make sense?

In nutrition, as in all other areas of science, there are some very well-proven facts that are truly beyond dispute, and then there are theories where the evidence is much thinner. There are two big obstacles to separating out the facts from the theories and misinformation:

  • A public information campaign starting in the mid 1970s presented certain untested theories as facts – theories since proven beyond a doubt to be wrong. These include the idea that a high carb, low fat diet is best for health, and that saturated fat and cholesterol is bad for the heart, while polyunsaturated vegetable oils are heart-healthy. In fact, the opposite is true – the evidence is overwhelming. Our current obesity epidemic dates to the dissemination of this bad advice. And yet the misinformation persists because the agencies that disseminated it can’t find a face-saving way to admit their error. (See this previous post for details.)
  • Most books and articles about nutrition do not differentiate between what’s known for sure – the facts backed by mountains of evidence – versus recent theories with thin support. So when one of these theories is debunked, people feel like they can’t trust any nutrition advice.

I don’t pay much attention to unproven theories from epidemiological studies. These are the iffy so-called “facts” that are constantly getting reversed. A couple years ago, the New York Times Magazine ran a cover story by Gary Taubes on the problems with epidemiological studies, and why advice from these studies is so often found to be wrong. Epidemiological studies follow large groups of people for long periods of time – what drugs they’re taking, what diseases they get, etc. – and make inferences about what caused what. The inferences are no more than hypotheses – an epidemiological study cannot prove causation – but the news media loves the hypotheses and disseminates them as fact. Worse yet, doctors sometimes act on these unproven hypotheses, to the detriment of public health.

Nor do I pay much attention to findings from controlled studies that haven’t been replicated. There are zillions of these, often extremely narrow in scope. If a study hasn’t been replicated, there is a chance that the finding was random – just a chance outcome. Also, the narrowness of most controlled studies makes generalized conclusions highly questionable. The observed effect may be trivial compared to larger effects that were not part of the study. You can’t draw general conclusions from a narrow controlled study without confirmation from other directions.

But not all nutrition advice is based on flimsy evidence. I do pay attention to nutrition principles that have been proven repeatedly in controlled studies, and especially when cross-confirmed by studies in completely different fields. One example is the indisputable danger to health of a high carb, low fat diet. Evidence comes from countless studies in multiple fields, including endocrinology, biological anthropology, and biochemistry (fat metabolism), along with studies of isolated populations still eating traditional diets. Another example of indisputable fact is the kinds of fats that are good for us (not polyunsaturated vegetable oils). Healthy versus unhealthy fats will be the subject of a future blog post.

Reality Check: Did We Evolve Eating It?

A quick and reliable touchstone for determining whether a so-called nutrition fact makes any sense is by reference to the diet humans evolved eating – the Paleolithic diet. The human genus first appeared on Earth about 2.6 million years ago. This was the start of the Paleolithic Era. From that time until just 10,000 years ago – the start of agriculture and the Neolithic era – all humans lived in hunter-gatherer societies.

The theory of evolution says that our bodies adapt to what is on hand. The individuals whose bodies were best able to use the nutrition from the available food lived to reproduce. Thus the food that was available to human beings for the first 2 million years of their existence is the food that the human body is adapted to eat. It defines good nutrition.

People in hunter-gatherer societies may suffer more frequently from accident and contagious disease, but non-infectious disease – heart disease, diabetes, cancer, colitis, multiple sclerosis, asthma, lupus, etc. – is virtually nonexistent. We know this from studying modern hunter-gatherer societies. The obvious culprit is diet – the new foods we’ve started eating that our bodies are not adapted to use. When hunter-gatherer societies switch from traditional diets to Western diets, they suddenly develop all the non-infectious diseases that afflict our society – diseases previously unknown to them.

While it’s impossible to know exactly what Paleolithic people ate, we can make some good guesses. One way we know is the structure of our digestive tracts, which are very similar to that of dogs and other carnivorous animals, and very dissimilar to that of herbivores (animals that eat only plants).

There is other evidence that we evolved as meat eaters. Fossil remains of large animals like wooly mammoths show marks from stone knives. Plus studies of modern hunter-gatherer societies show that most of their calories come from animal food. From the American Journal of Clinical Nutrition:

Our analysis showed that whenever and wherever it was ecologically possible, hunter-gatherers consumed high amounts (45–65% of energy) of animal food. Most (73%) of the worldwide hunter-gatherer societies derived >50% (56–65% of energy) of their subsistence from animal foods, whereas only 14% of these societies derived >50% (56–65% of energy) of their subsistence from gathered plant foods. This high reliance on animal-based foods coupled with the relatively low carbohydrate content of wild plant foods produces universally characteristic macronutrient consumption ratios in which protein is elevated (19–35% of energy) at the expense of carbohydrates (22–40% of energy).

We also know some practical things. Paleolithic humans did not keep animals – they hunted them. You don’t milk animals you hunt. And we know that until the Neolithic era 10,000 years ago, most people over the age of 3-4 (after weaning) did not have the enzyme to digest lactose, the sugar in milk. Many people today still lack this enzyme, and are lactose intolerant.

One reason that anthropologists think that Paleolithic people did not eat grain is because it was virtually impossible to gather before agriculture, when we specially bred wheat so it would stay on the stalk and be easier to harvest. Also, grain is tiny – it’s just too time-consuming to gather this.

Until very recently, it was thought that humans starting cooking their food only 200,000 years ago, and for most of their evolution ate their food raw. A Harvard anthropologist recently debunked this idea in a fascinating book called Catching Fire. He argues that it was actually the discovery of cooking that allowed our brains to grow so large – that cooking made us human. I thought his argument was very convincing, though some don’t believe it. Many people still use the touchstone of “can you eat it raw” to determine whether Paleolithic people ate it. You can’t eat grain raw; cooking is required to remove toxicity. But even if you allow that Paleolithic people cooked, they probably did not eat grain because of the harvesting difficulty.

In short, here’s what we know: Our ancestors ate the meat of animals they hunted – mammals (herbivores), birds, and fish. They ate eggs only rarely (in spring, when they could find them and climb up to reach them). On rare occasion they’d eat honey, but they had to brave bees to get it. The only milk product they ate was mother’s milk for the first few years of life, and never again after they were weaned. They ate the plants they found growing in the wild – mostly the leaves, fruits, and flowers. They probably only ate roots or seeds in winter when they were desperate since these are harder to harvest and may contain anti-nutrients (cause a belly ache). “Seeds” include grain, beans, and tree nuts – all of these are plant seeds of one kind or another. In particular, they ate little or no grain – the seeds of plants in the grass family. Note that corn is a grain – a corn stalk is a giant stalk of grass. Wild corn was originally a small plant; it’s now big due to agricultural breeding.

Paleolithic people ate plenty of red meat containing saturated fat, but relatively little carbohydrate. Carbohydrate can take the form of starch or sugar, and is mainly found in roots and seeds (the storage parts of plants), sweet fruits, and honey. All but roots are seasonal, honey is dangerous to obtain, and many roots and seeds are toxic raw and difficult to harvest. Paleolithic people did not eat refined or processed food of any kind – no white sugar, white flour, white rice, or vegetable oil. You can’t make any of these things with stone-age technology. If a food can’t be made with a stone knife and a sharp stick (and perhaps fire), they didn’t eat it.

When you evaluate nutrition advice, the general principle is this: Advice that moves you away from what we evolved eating is highly suspect and probably wrong. Advice that moves you closer to what we evolved eating makes common sense and is probably right.

Examples of Bad Advice:

The advice to eat lots of polyunsaturated vegetable oils cannot be right because these were almost nonexistent in the Paleolithic diet, except in the form of whole nuts. (We now know why excessive vegetable oil is so bad for us – more in a future post.) The advice not to eat red meat with its saturated fat and cholesterol makes no sense because we evolved eating plenty of both. The advice to eat a grain-based, high-carb diet makes no sense because we didn’t even eat grain until 10,000 years ago, and no hunter-gatherer society eats a carb-based diet. In fact, dietary carbohydrate is not necessary for life or health. Traditional Inuit (Eskimos) don’t eat any carbs at all since plants don’t grow in the ice, and they are very healthy. The idea that cow’s milk must be a part of any healthy diet does not make sense.

Examples of Good Advice:

The advice to eat less processed food does make sense. Processed food is a very recent addition to our diet, and science has clearly demonstrated many ways in which it harms health. The advice to eat 100% grass-fed beef does make sense, and is important, as we’ll see in my upcoming post about fats. The wild animals eaten by paleolithic people grazed on grass, their natural food.

In general, be suspicious of what Michael Pollan calls “nutritionism”, advice based on the nutritional breakdown of a food rather than the whole food. Avoid weird foods that require advanced technology to produce, no matter what their health claims. Why? Because we don’t know what we don’t know. We can be sure that the Paleolithic diet defines good nutrition, but we can’t reliably list all the micro- and macronutrients that make it so.

Why Nutrition Matters

Beyond the obvious motivation to live a long and healthy life, nutrition matters for this reason:

Not all compulsive eating is emotional eating.

For people whose bodies are sensitive to the quick-digesting carbs we are not adapted to eat (virtually everyone who is overweight), compulsive eating has a physiological component.

Some people can eat a diet high in white flour and white sugar and suffer no obvious ill effects. Others develop unstable blood sugar, carb cravings, and Metabolic Syndrome (obesity, insulin resistance, diabetes). At some point, people in recovery for emotional eating need to address this or they won’t fully reach their goals.

I’m not saying you can never eat another brownie. Nutrition information is just information – it’s not a rule. Not every eating decision has to be based on nutrition. Please don’t try to follow a 100% Paleolithic diet and then pummel yourself when the very thought of not eating grain or sugar makes you crave it.

Just be aware. Notice how refined carbs affect you – both immediately after eating and a few hours later. You may eventually decide you prefer to eat them less often because of how they make you feel.

Thoughts? Comments? I’d love to hear them.

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19 comments to Good Nutrition: Myths and Facts

  • “Notice how refined carbs affect you – both immediately after eating and a few hours later. You may eventually decide you prefer to eat them less often because of how they make you feel.” This is exactly what my experience has been! I never thought I could voluntarily skip bread or desserts. But after getting a certain point in my recovery from binge eating disorder, I got very in touch with my body. Without all of that extra food circulating in my system, I was able to discern more easily how particular types of foods made me feel. Most days I choose to avoid sugar and refined carbs. Not because I’m depriving myself, but because I’m taking care of myself. –Sunny

  • Xanadu Xanadu

    I would find a “true” Paleo diet too hard to maintain (no dairy? very little grains? only grass-fed beef?) but when I stopped worrying about doing it perfectly, I got a lot of body wisdom. I eschew almost all processed food, make my own salad dressings and sauces, and have reduced the amount of white flour and sugar (as well as carbs in general). I try to pick my proteins carefully, cage-free eggs and organic beef, but I do like yogurt and cheese and I do need some whole grains and plant fats in my diet just for variety. And sometimes I just gotta have ice cream. It all works out for me once I realized that “ideal” eating is just that, an ideal and an inspiration rather than a mandate.

    The other day I wanted to see what would happen if I ate the way I used to in Stage 1. I had (at a birthday party, conveniently!) pizza, cola, and a piece of cake. No overeating, but lots of white flour and sugar. Well, the difference in my body was huge and very frightening. I began panicking and shaking, and fell into despair over the littlest things. I was impossible to live with for about 6 hours. My body was craving broccoli, spinach, and chicken. When I ate that, I felt much better. To think I used to claim I wasn’t affected by food choices!!

  • ds ds

    Im eating paleo a lot. I feel so much better that way, I believe we evelved to eat like this and so it is the best we can do for our bodies. When I binge on grains and sugar I can feel it – my joints ache, stomach bloats, low energy…
    Yet, I can´t stop myself from binging on it, even though I know Im hurting myself…sad

  • It’s one thing to choose to eat grain and sugar now and then because you feel like it. It’s another thing to feel out of control with it, like you can’t make the choice that you want to make. That doesn’t feel good!

    Grain and sugar have some affects on the body that are addictive. There have been various things written about what the exact mechanism may be, but whatever it is, there’s little question that there is something physiological happening. It’s not just emotional eating.

    I think that recognizing this is key. The way you approach an addictive substance in terms of self-talk, how you think about it, is quite different. You look at it very differently.

    - Sheryl

  • ds ds

    I see how carbs can be addictive, physically addictive – specially sugar and grains, but other high carb foods too. but I do binge eat. a lot. mostly when Im bored or when I dont know how else to cope with situations…and then I usually go after carbs (mostly becasue i dont eat them “normally” – and when Im fine, I dont have slightest problem eating the way I consider healthy, because I do enjoy taking care about myself like that).
    I´d also eat just about anything that is in my reach at the time (even like 5 apples and bananas, lots of nuts – anything really, just so that I can eat, but yes, preferrably carbs and simple sugars).

  • Sandra Sandra

    I’m concerned about all of the hormones and antibiotics in meat. The meat of today is not what our ancestors ate. Also, considering how much land and energy it takes to raise cattle, in good conscience I cannot become an eater of animal flesh.

  • Hi Sandra,

    It’s actually worse than that. By force-feeding animals grain (which is why they need the antibiotics in the first place), they change the natural of the fat in their meat so it becomes high in omega-6 fatty acids (like the grain they eat), versus high in omega-3 fatty acids (like the grass they are meant to eat). This creates very serious health problems. I’m working on another post on this topic – probably for the newsletter in November.

    - Sheryl

  • Great post and interesting comments, too. I agree that when you recognize all this, and learn how to discern what to believe, that is the first step in avoiding what we sometimes crave. I’m certainly not always successful, but I desire it much less now that I know what it does to my body.

    Kelly

  • Beth Beth

    Sheryl, great blog! Just found you, and expect to be a regular reader. One comment re paleo … I’ve recently begun following a mostly paleo/primal diet, though I’m also including dairy (cheese and butter from grass-fed animals).

    While I obviously find the argument re evolutionary diets compelling, isn’t it also true that modern H/G societies whose diet changes also experience an environment change? I.e., people don’t just eat a Western diet, they adopt other Western traits (becoming more sedentary, more stress, etc). I realize that diet is key, but there may be other factors that also contribute to our rate of disease.

    BTW, this is going around on a couple of the other primal blogs: http://www.youtube.com/watch?v=eREuZEdMAVo If you haven’t seen it, definitely recommend. It’s the results of a 6-month Stanford study from 2007 comparing Atkins, Zone, LEARN, and Ornish diets. Lower carb wins on both weight loss and health parameters basis.

  • Beth Beth

    Oops. One other thing re the video link above. I found the section from about minutes 38-45 extremely fascinating on the relation of insulin sensitivity/resistance to both health parameters like blood pressure, etc and success with low fat or low carb diets. Highly recommend!

  • Sandra Sandra

    Normal Eating for Normal Weight just arrived in the mail. As a compulsive eater and in and out of OA rooms for a number of years, I am looking forward to opening the book. Also, I read the Zen of Eating years ago, and I am pleased to see Ronna Kabatznick’s comments on the front cover.

    Yes, I have weight obsessions and food obsessions, but I also have “eating plan” obsessions. I am always searching for the perfect food plan. I hope the book helps since my weight is at an all time high and my spirit is at an all time low.

    Thank you for this opportunity.

  • smoothe smoothe

    I’ve just read all that you said above, and it makes perfect sense. You communicated it very well. It’s the first time I’ve seen the whole idea in writing, rather than just bits and pieces.

    I would like to see information on how to get along on a diet of what’s widely available in the stores, because realistically, that’s what’s available to most people. Should you eat more of something or less of something to counteract the omega 6 instead of omega 3 thing? That kind of information. Unless you include that, the information about what happens to the food supply when it’s subjected to the kinds of abuse it’s regularly subjected to is deeply frightening and that’s all it is. I mean, it’s fine to say eat only organic, but most of the world’s food supply is not organic. It’s abused.

    Also, do you know anything about genetically modified foods – what kind of effects to expect, and how to get along with that?

    I’m afraid it sounds like I’m being argumentative here. Please believe me, I’m truly not.

  • Sorry for the delayed response – I’ve been on the road a lot in the last week or so. Glad to hear from you, Sandra. Thanks for your note.

    Beth wrote:

    > isn’t it also true that modern H/G societies whose diet changes also experience an environment change? I.e., people don’t just eat a Western diet, they adopt other Western traits (becoming more sedentary, more stress, etc). I realize that diet is key, but there may be other factors that also contribute to our rate of disease.

    Not necessarily. For example, the Inuit started trading for sugar and tea while still living a traditional lifestyle. Based on what I’ve read, the big change was in diet, not lifestyle.

    I haven’t been able to watch the video yet. Apparently many other people are trying to watch it because it keeps stalling. Now I’m downloading it, but that’s slow, too, because the file is gigantic. But I’m interested to see it.

    Smoothe wrote:

    > Should you eat more of something or less of something to counteract the omega 6 instead of omega 3 thing?

    This is a big topic – it will be the subject of the November newsletter.

    Smoothe wrote:

    > do you know anything about genetically modified foods – what kind of effects to expect, and how to get along with that?

    The effects on the environment of genetically modifed food (generally bad) are understood better than the effects on the body. Many people avoid genetically modified food because there always seem to be unintended and unanticipated consequences of this type of manipulation – safer to just stay away.

  • Beth, I finally did watch the Stanford video. Great info – thanks for posting it.

    - Sheryl

  • Cynthia Cynthia

    I am new to “Normal Eaters” have been in OA – Greysheeter’s and AA for years. In and out of abstinence regarding food. All or nothing is how I have been virtually perfect and then perfect binging as soon as I pick up certain foods. Looking forward to learning more – I do beleive in Higher Power but I also do believe it is in us. Thanks, Cynthia

  • You make a really good point about how some nutrition information that is established and accepted by everyone is often combined with less-proven data and supposition. This is why it’s imperative for consumers and parents, especially, to pay attention to the indisputable facts (saturated fats–bad, organic fruits and vegetables–good).

    Very well said. I’m glad I found your blog.

  • > pay attention to the indisputable facts (saturated fats–bad…

    As I say in this post, I challenge the “indisputable fact” that saturated fat is bad – strongly challenge.

    - Sheryl

  • That’s interesting! Thanks for the link. Still, 30,000 years is a blink in time compared to 1.5 million years of paleolithic evolution. The article is misleading on that.

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