Ask the grumpies: What is real when it comes to nutrition advice?

Sandy L. asks:

Nutrition advice. What is real. I find it hilarious that eggs and coconut oil were such villains in the 90s and now they are “the perfect food”. I bought an old cookbook a few months back and it was talking about avoiding coconut oil. It made me laugh.
Now fat is okay but sugar is bad.

First, a tiny rant from #1, “In which research on “nutrition” is nonsense.”:

#1: haha:

#2: People underestimate how much they eat?

#1: People write articles based on stupid, meaningless data and then use those articles to influence policy recommendations.

#2: The nhanes is the best information we have for a lot of things.

#1: It’s true. But the nutrition stuff is messed up. When asked how they eat, people misreport. Then the researchers convert the amount of various foods into calorie amounts, using incorrect databases that are filled with wrong info. Then they change methodology. Then reports are based on those data…

Most of the nutrition database info (about how many calories are in the reported food intake) hasn’t been actually checked scientifically.

For example, on the plane I had some beef. What cut was it? I have no idea. But different cuts of beef can have TWICE as much kcal as another cut. Which one do they write down? it’s kind of random!

It’s a good thing our policy is so coherent… oh wait…

People should also read Dances with Fat.
Enjoy, Grumpeteers!

#2 notes that you may be interested in reading this article about the history behind sugar and nutrition .  A bunch of people in high school had/got to read a book about the vast Sugar conspiracy for their world history class at our high school back in the 1990s.  It had some pretty horrifying stuff in it about sugar and tea and trade.  The capitalist conspiracy is ancient and vast!  The sugar dynasty is powerful and has been for centuries.

But…. there’s also non-political-economy reasons we don’t know a ton about nutrition.  The first is that nutrition is incredibly complex and there’s a lot of heterogeneity so it’s just hard to tease things out.  Generally, we start with looking at correlational evidence from places like the Framingham nurse’s study.  Those correlations provide headlines about eggs being bad when it may actually be the nitrates from bacon (eaten with eggs) or a million other things.  But correlations are a good place to start when you’re trying to figure out how things work because it narrows down the testing frame.  Then after correlational studies we can move into animal trials or human trials.  Generally that’s when things don’t pan out– there really wasn’t anything wrong with eggs, so randomized controlled trials failed to find anything wrong with eating eggs.  There was correlation but not causation.

What is real?  Who knows!  It seems likely that eating whole grains and unprocessed food and getting fiber and nutrients is a good thing.  But maybe not for everyone and maybe not to extremes.  I’m interested in seeing where all the research on gut flora ends up going.  (And, TBH, I’m really interested in getting better smelling underarm flora…)  Should you drink milk or eat meat?  Who knows!  Me, I generally listen to what I’m craving and pay attention to how I feel after.  That doesn’t always steer me right– sometimes I lose my ability to comfortably digest say, beef or raw veggies and that ability has to be rebuilt, but it’s the best idea I’ve got.



52 Responses to “Ask the grumpies: What is real when it comes to nutrition advice?”

  1. nicoleandmaggie Says:

    I have been doing activism this week, I just haven’t been mentioning it here!

    Today is a really good day to call about DACA and CHIP whether you are red state or blue state.

    Tell your blue state senators to hold strong– no spending bill without DACA, and depending on how you’re feeling no spending bill without CHIP funding. It is outrageous that republicans are holding CHIP funds hostage. I cannot imagine the stress parents of kids who would not be alive without CHIP are feeling right now. It is unconscionable.

    Red state folks– tell them to stop being jerks about DACA and CHIP. They need to pass clean CHIP funding and stop playing with kids’ lives for political points. DACA is good for the US economy so they should pass the DREAM act. has scripts for you.

  2. Omdg Says:

    Real takeaways: 1) most people need to eat less. 2) exercise because it makes you fitter, not just to lose weight. 3) eat a variety of foods. 4) avoid gorging on cakes, cookies, potato chips, etc. 4) actually, just avoid gorging period. 5) if you feel full you probably just ate too much.


    • Leah Says:

      One of my favorite books on eating is Mindless Eating by Brian Wansink, and he talks about the “mindless margin.” There are so many tricks to help you eat less, like eating dinner on salad plates. I use our “dinner plates” as serving dishes and use little plates (salad or sometimes even dessert) to eat. I use little kid bowls for ice cream. Even when I have a “huge bowl,” it’s not as much ice cream as having a soup bowl.

      I agree with you on your points, especially as there’s so much we still don’t know about eating.

      • omdg Says:

        Yes! Eating out of small bowls has been tremendously helpful to us as well. That and not feeling obliged to have a big meal if we’re not that hungry. It’s really hard not to gain weight with our delicious food and our culture of overeating.

  3. Solitary Diner Says:

    I really enjoyed Michael Polin’s In Defense of Food, which looks in greater detail at the inherent difficulties of nutritional research. I try to live by his recommendations to “Eat Food. Mostly Plants. Not Too Much.”

  4. chacha1 Says:

    When it comes to nutrition, I think the easiest guideline to follow is: Consider what you habitually eat. Now consider how your body looks and feels (digestion, weight, sleep quality, energy level, aches & pains, skin problems, EVERYTHING). Draw a conclusion: is what you habitually eat good for you? If not, CHANGE IT.

    It’s pretty obvious when a consumable product is junk.

  5. pyrope Says:

    I think there is pretty strong evidence that beef consumption (not the meat itself necessarily, but the chemical-rich processes that go into meat production) increase risk of cancer.
    Beef is also responsible for an estimated 18% of greenhouse gases and a litany of other environmental problems. So, if there’s one thing to try to reduce, it’s the hamburger.

    • Jenny F. Scientist Says:

      No, you’re mistaken. That paper doesn’t say beef, or the chemicals in meat production. It says processed red meat including horse, goat, etc.
      “On the basis of the large amount of data and the consistent associations of colorectal cancer with consumption of processed meat across studies in different populations, which make chance, bias, and confounding unlikely as explanations, the majority of the Working Group concluded that there is sufficient evidence in human beings for the carcinogenicity of the consumption of processed meat. Chance, bias, and confounding could not be ruled out with the same degree of confidence for the data on red meat consumption, since no clear association was seen in several of the high quality studies and residual confounding from other diet and lifestyle risk is difficult to exclude. The Working Group concluded that there is limited evidence in human beings for the carcinogenicity of the consumption of red meat”

      The IPCC and the EPA state 24% of all greenhouse gases are from all agriculture combined, including forestry/deforestation. It is not possible for 18% to be from beef cattle alone. Really, it’s not.

      • Linda Says:

        It seems there’s always another angle to look at, and I was intrigued to see something recently about how raising grazing animals traditionally is actually good for the environment. Something about how grazing animals (like cattle, bison, etc) nurture the health of grasslands, and how grasslands are important in carbon dioxide cycling or something like that. When I think about the extensive Plains systems in North America, Asia, and Africa, this seems like it could be a valid line of thought. Few would argue that raising beef cattle on grain and in CAFOs is good for the environment, but maybe if they were grazed like they were traditionally, that’s not a terrible thing. (And, yeah, it’s still not sustainable for the current population to eat a lot of red meat.)

      • Jenny F. Scientist Says:

        I live in a rural, mountainous area where most of the ground is unsuitable for plowing and there are two cows for every human being who lives here and they are, mainly, grazed on otherwise unusable land. Also, they are local and delicious; there’s a butcher in town that sells fresh meat from their own farms.

        I’m not arguing that our current red meat consumption is sustainable without things like CAFOs – it’s not – but beef does not, in and of itself, cause cancer and/or 18% of all greenhouse gas emissions. No. We have data for this, we don’t need to make stuff up to make it look worse, it’s bad enough as it is.

  6. becca Says:

    What is real?
    *In general, a diverse gut microbiome is better than a limited gut microbiome. Microbes that make short chain fatty acids are probably good.
    *Intermittent fasting is probably the most useful single thing you can do.
    *If you like following a coherent diet, follow what the nutritional literature is using as “the mediterranean diet”, unless you have high blood pressure already, then look for the “DASH diet”. Avoid fads.
    *Don’t eat burnt food.
    *Our diets likely contain way more sugar than would be optimal.
    *There are diets with radically less meat than is the current Western norm that are healthy and balanced.
    *Glycemic index matters, but is likely individualistic
    *For minimizing heart disease and metabolic syndrome, there appears to be a hierarchy of fats: omega 3 rich fats > unsaturated fats> omega 6 rich fats ~ saturated fats > trans fats. Avoid trans fats, though the trace amounts naturally in cheese are trivial compared to where margarine was at 5-10 years ago. If you eat a typical Western diet, you can likely benefit from swapping out saturated fats for omega 3 rich fats (e.g. salmon for non-grass fed hamburger, or high omega eggs for standard eggs, or olive oil for butter).
    *Green tea is good.
    *Vegetables are good. Probably not all are created equal, but frozen and canned veggies are underrated.

    What is not known?
    *Best practices on optimal timing of consumption/dose/types of/microbiome context of fiber. Some fiber is good, but don’t go crazy if you already have polyps.
    *If red meat is good. If milk products are good (if you have to prioritize milk products, prioritize fermented ones without sugar). If industrial farming is making lots of things significantly less good.
    *If artificial sweeteners are the devil.
    *How much wine to drink for health.
    *How much salt someone with low blood pressure should have, and if low blood pressure has negative consequences.
    *If coffee is good for health. It is good for life.

    Eat Drink and Be Healthy has a new edition out! With chapter for climate change. Not sure that really gets at the core of nutrition evidence, but it made me want to read it :-)

    My favorite diet advice was actually the stuff in What to Expect When You’re Expecting. It was a nice change to focus on “here are all the yummy fruits and veggies in this color group” and “eat more of this”.

    As a side note, as an immunologist I see body fat as an immunological and neurological signaling organ in it’s own right that is part of an adaptive buffering effect of inflammatory processes that can be overwhelmed.

    • nicoleandmaggie Says:

      … intermittent fasting is a fad …

      • Leah Says:

        My dad is really into intermittent fasting. I hear so much mixed stuff out there tho about it. I hear his arguments for it, but I’ve also heard that breaking the fast then puts a heavy load on your system.

        I’ve been thinking a lot about how frequency of eating influences our teeth. I’m trying to reduce my snacking to help my teeth be healthier.

      • nicoleandmaggie Says:

        As someone with insulin resistance who also gets really cranky with low blood sugar, I am seriously skeptical about the universal efficacy of intermittent fasting.

      • nicoleandmaggie Says:

        (There’s also some pretty good evidence that when pregnant women fast their kids get health problems later in life– Doug Almond and coauthors)

      • Becca Says:

        As a strategy for weight loss, it may be a fad. And I’m not saying we know how to do it optimally.

        But delibrate fasting is thousands of years old, and periods of significant calorie restriction are almost certainly the norm for human evolution.
        The animal studies on calorie restriction and lifespan are rigorous and far reaching. To say it won’t benefit humans is to argue mechanisms conserved in everything from worms up simply don’t apply.

        If you don’t hook yourself up to an IV drip at night, your body can handle short times without food. Just because an idea has been taken up by hipsters doesn’t mean it’s wrong. You don’t have to instagram your toast for avocados to be healthy, and you don’t have to follow whatever intermittent fasting person writes books for Silicon Valley execs to pay attention to when you eat less.

        At any given time, about 50% of Americans are “on a diet”. With the exceptions of some diabetics and people who can actually follow DASH for hypertension, I think they’d all be better off with intermittent fasting. None of which is to say that deliberately controlling your food intake in a systemic way like a diet is the ideal approach, just that if I hear another rant about how our ancestors ate from a non anthropologist paleo adherent, my face may actually freeze like that with eye rolling.

      • nicoleandmaggie Says:

        The animal studies on fasting are inconclusive. The animal studies on calorie restriction are strong for mice, not as strong for primates. Intermittent fasting is everything that you say about other fads. Unproven, known to be dangerous for some populations. No different than low carb. (And our ancestors doing it is exactly what you say about paleo here! Not a good argument. Fasting is a way to deal with winter food shortages—doesn’t mean it is healthy when food is plentiful!). Listen to your own arguments.

      • Jenny F. Scientist Says:

        I was going to go into a whole Rodent Studies Are Not Human Studies, Are You A Mouse, but you seem to have it covered.

      • nicoleandmaggie Says:

        I use mcarthur genius sendhil mullainathan as an example in class—he ate one microwave burrito a day after the mouse evidence came out for restricted calories.

      • Jenny F. Scientist Says:

        I usually use the human success rate of drugs that passed a mouse trial… it is LOW.

      • nicoleandmaggie Says:

        Mine is just a brief example discussing one type of problem with external validity

      • nicoleandmaggie Says:

        p.s. I’d love to see the exact number!

      • omdg Says:

        Intermittent fasting probably helps people because many find it easier to eat nothing than to eat less. I know I do. I have much less trouble avoiding weight gain when I eat only vegetables and fruit for dinner than when I eat a “real” meal. Fad, perhaps. But probably effective.

      • nicoleandmaggie Says:

        Intermittent fasting though doesn’t usually result in weight loss (or at least that’s mixed). The claims are health only, and they’re really not proven.

      • Omdg Says:

        Then yes: fad.

    • Linda Says:

      I won’t fast by choice. Going without food makes me very cranky and has led to episodes of dizziness for me in the past. I think humans are the only animals that would withhold food from themselves by choice, so we should probably heed that. Do people often eat too much? Sure. But I don’t think abstaining from food is going to help with that issue in the longer term.

      Other than that, I can’t add much to the original post which is sound.

      • nicoleandmaggie Says:

        I kind of suspect that with the human restricted calorie trials, it’s not the calorie restriction that causes benefits, but the fact that they’re eating watery fruits and vegetables all the time. But I wouldn’t bank on that!

  7. Sally Demarest Says:

    This topic has come up a lot in our house lately because several of my daughter’s friends are going vegan, counting sugar grams, etc. She’s feeling a lot of peer pressure to be vegan (and there has been some food-shaming, when she eats yogurt at lunch, for example), but she doesn’t want to eat a vegan diet, and I don’t think that, at age 12, she should get focused on that kind of food restriction and obsession. It makes me mad that she is stressing over not being vegan when she doesn’t want to be vegan. I have a feeling this is a California kind of problem. I mean, I guess it’s better than being pressured to smoke cigarettes (which was the kind of peer pressure I faced), but it’s messing with her head.

  8. Debbie M Says:

    Vitamin C deficiency leads to scurvy. Having sugar in your mouth all day (like in those cultures where they chew on sugar cane) rots your teeth.

    It’s the slow poisons that are hard to figure out.

    I always feel fine and the numbers my doctor measures are great. Nevertheless, I can’t help thinking that I should eat way more produce and less sugar.

    I’ve decided that anything in moderation is fine, though I do try to greatly limit hydrogenated oils and nitrates/nitrites. By which I mean I don’t buy them at the grocery store, but I don’t worry about them when I eat out or at parties.

  9. bogart Says:

    Honestly? On average, we (in developed nations) are far outliving earlier centuries of human beings, and while clearly there are those among us (those with food allergies, PCOS(?), others for various reasons) who do need to consider dietary issues at a detail level, personally I figure that eating more-or-less healthy stuff most of the time based on what we think we know while avoiding fads is likely good enough for my purposes. But then again, I’m a known satisficer, so, make of that what you will.

  10. contingent cassandra Says:

    Another good read is She hasn’t been posting a lot lately, but there’s a backlist, and she apparently has a new piece in the The Atlantic, and makes reference to other well-established nutritionists who focus on intuitive eating and recovering from the ill effects of dieting culture.

  11. First Gen American Says:

    And the question is still unanswered. I even spoke to a “nutritionist” as part of one of my work wellness benefits and she sounded a lot like she was touting the paleo diet. I don’t eat enough protein she says and that is why I feel hungry often. I asked about oatmeal for breakfast and she said it was better to do eggs and meat as oatmeal didn’t have enough protein in it. Grrr….this doesn’t sound right either. For the record, I think I get plenty of protein. The all protein breakfast had no positive effect on fullness and I left feeling like I was no smarter after the 40 minute call than when I started.

    So I still feel lost. The only things that I am fairly certain about my body are:

    1). I trust what comes out of my garden/yard and my body feels best after eating fresh and wholesome pesticide free produce.
    2). I do need protein or I feel hungry within an hour of eating.
    3) deep fried things taste delicious but they always make me feel gross after and make me break out.
    4) brown rice feels more filling than white rice.
    5) my mom survived months on nothing but oatmeal, milk, eggs, potatoes and kraut during her long winters as a child. If these few things can sustain life, they can’t be bad.
    6) bread and cheese are like crack. I can never get enough and know these are my Achilles heel.

    Thanks for the post.

  12. becca Says:

    The calorie restriction literature goes back to 1915, and has indeed included successful trials in non-human primates, at both U-Wisconsin ( Colman RJ, Anderson RM, Johnson SC et al. . Caloric restriction delays disease onset and mortality in rhesus monkeys. Science (New York, NY) . 2009;325:201–204. doi:10.1038/nature11432) and the National Institutes of Aging (Mattison JA, Roth GS, Beasley TM et al. . Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study. Nature . 2012;489:318–321. doi:10.1038/ncomms14063). The main discrepancy between the two groups studying non-human primates was whether lifespan was extended, or only “healthspan”.
    There is a tremendous wealth of literature (thousands of papers) on the molecular pathways involved in both calorie restriction and aging (including Sirtuins, reactive oxygen species, telomerase, autophagy and others).

    You can argue as to whether intermittent fasting is a viable approach to mimic the impact of calorie restriction, but not whether calorie restriction can positively impact health. It’s established science.
    Again, I don’t think intermittent fasting is perfected yet- but it is far more of an *attempt* at a science-informed approach than paleo and most diet fads.

    That said, I am in no way arguing that pregnant women should try unsupervised fasting, but that is a specific subpopulation with specific health needs. I’m actually pretty committed to the hypothesis that everything that is unusual about human pregnancy (including the relative lethality of human childbirth relative to other primates) is the result of specific metabolic strain caused by the vast calorie needs of developing human brains, but that is far *less* established and *more* speculative science than the evidentiary standard behind calorie restriction (in my opinion the evidence for the metabolism hypothesis is much stronger than the chief competitive hypothesis- that human childbirth is dangerous because we walk upright- but all of this evolutionary development stuff is comparatively difficult to address empirically.).

    • nicoleandmaggie Says:

      You’re moving goalposts. Intermittent fasting is not calorie restriction (indeed, in practice it is entirely the opposite– humans in the recent calorie restriction trials were ALWAYS eating low calorie high volume fruits in an effort to not feel hungry). And, as I said before, it is NOT clear that it is the calorie restriction that is benefiting or the ways people are forced to deal with calorie restriction without feeling hungry.

      Pathways stuff is interesting, but economists do not find them conclusive. Biologists and medical scientists hypothesize pathways and show parts of pathways but often it turns out that the thing they’re claiming is at the end of that pathway doesn’t really happen even if one link of the chain does. Pathways research doesn’t include general equilibrium effects, or, for that matter, linking inputs to final outcomes.

    • nicoleandmaggie Says:

      Which is not to say that pathways research is garbage, but that it does not usually and should not overclaim.

  13. CG Says:

    For the last couple of years I’ve adopted a modified (and very mild) version of intermittent fasting. I try to go at least 13 hours every day without eating (no eating after dinner), and once a week I don’t eat dinner since I teach an evening class and don’t get home until 9pm. I also try to keep my dinner portions small on the normal dinner nights. I, too, get cranky if I don’t eat regularly, so any fasting I do really needs to be while I’m sleeping. I love to cook and eat, and have found that this approach results in a “reset” of my weight every week. I am not losing weight with this approach (and I could probably afford to lose 5 pounds or so) but I am maintaining it and still enjoying eating. I also don’t think this is so extreme that it will hurt me in any way. YMMV.

    • nicoleandmaggie Says:

      I eat less but gain weight if I skip breakfast. I skip dinner if I’ve had a big lunch of haven’t had to think much that day because I’m not hungry. I don’t think that’s what people mean when they talk about intermittent fasting. I suspect, but have no proof, that some of my metabolic problems may stem from the starve/binge thing I had going in high school because the cafeteria was so bad, where I ate very little during the week and ate a lot on weekends when I was at home. Also I grew a couple of inches after I graduated high school (age 18), which is pretty unusual for a woman. But who knows, maybe that was healthy.

  14. Joe Says:

    Great post! Explaining that correlation does not equal causation has become routine in my profession as a dietitian. Frequently the media will use a small study with an n<100 and will put out a big headline while ignoring the limitations listed in the study. Thanks for sharing!

  15. Link Love | Grumpy Rumblings (of the formerly untenured) Says:

    […] nutrition research is so messed up (Here’s our much shorter post on the same […]

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