rachelmanija | Debunking food, fat, and fitness myths

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Debunking food, fat, and fitness myths

I would like your best recs for in-depth articles, studies, or books on the most cutting-edge current knowledge about nutrition, body weight, and health.

I am NOT interested in basic articles about very well-known ideas like fat will kill you, carbs will kill you, meat will kill you, anything your grandma wouldn't recognize as food such as everything but cabbage and turnips will kill you, etc.

I am also NOT interested in articles with a primarily political bent (i.e., "pushing diets on women is based on sexism/capitalism not science;") I agree with that, but I'm looking for stuff where the meat is science and the politics is the side dish rather than the reverse.

I'm looking for more in-depth, up-to-date information on topics including but not limited to...

- Do we actually know anything about nutrition, given the every-five-year swings between "eggs are cardioprotective/eggs are a heart attack on a plate," "fat is the Devil/carbs are the Devil," etc? If so, what is it and how do we know it?

- What is the actual science on grains (and no, I don't mean Wheat Belly)?

- What is the best and most cutting-edge knowledge on gaining strength?

- What is the actual science on the causes of Type 2 diabetes, why its prevalence has risen so much, and its association with obesity?

- What is the actual knowledge of the diet and health of "cavemen?"

- What is the actual science on being fat, thin, and in-between in terms of health? For instance, is it better to be fat and active than "normal weight" and sedentary? (I know the answer but I'm looking for something that goes into this in-depth.)

- What is the deal with "calorie reduction makes you healthier and live longer" vs. "dieting is bad for you?"

I'm already familiar with Michael Pollan, Barbara Ehrenreich, Mark's Daily Apple, Diet Cults, Body of Truth, and The Starvation Experiment. And lots more but those are the things I get recced a lot already.

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I was looking into IF for myself recently and the most common working theory seemed to be that fasting can throw hormones out of whack and the menstrual cycle makes people more sensitive to that. So some women have a horrible time with their cycle becoming unpredictable or more difficult to deal with in some way. I can't seem to rustle sources out of my browser history anymore, possibly I was reading up on that longer ago than I think I was, but you might not need to worry about issues with intermittent fasting if menopause is in the mix for you.

Having said that, solid medical research on intermittent fasting seemed pretty thin on the ground in general. I do remember reading something about women probably doing better on less severe restriction because it was less likely to accidentally disrupt other things, so 12-16 hour fasts instead of all day or skipping a single meal everyday instead of something like 5:2 or a multi-day fast. Whether that reduced or negated some of the claimed benefits seemed unclear. But then pretty much everything I read was constantly emphasising that there's little proper research yet, and what has been done is mostly skewed to only one form of fasting when people are practising lots of different forms. So lots of we don't know what we don't know and etc.

If you happen to delve more into fasting and turn up any research that looks solid, I'd be super interested!

I didn't think to say before because it's a lot more specific than just general will carrying some extra weight increase my Type 2 risk type research. But I was specifically looking at IF because I have insulin resistance and endocrine disorders among other issues so I've been researching and tweaking my diet in that vein for a long time now. So if stuff along that line might be helpful, feel free to hit me up and I can probably rustle up some sources.

I also see this linked around occasionally so you might have seen it before, but Can We Say What Diet Is Best For Health? always strikes me as a decent summary of what we do and don't know about some of the more common diets and it comes with bonus citations and also being somewhat relatively recently published.

The "never train the same muscle groups on consecutive days" is actually one of the things I was wondering about. Everything I've ever read says that, but after one month on crutches in which I had to do the same weight-bearing exercise every day whether I liked it or not, I've broken through a strength plateau and now have bigger arm muscles and noticeably improved upper-body and grip strength. I was never able to get that with standard weight training every other day or every three days.

Thank you!

Thank you! Yes, I'd be interested, thanks. Insulin resistance and relationship to diet was one of the things I was specifically wondering about.

Oh cool, okay, I'm glad I mentioned it then! I generally assume it’s too specific for people unless they mention already having diagnosed issues with insulin so I try to avoid giving people the massive brain dump below unasked, haha. Caveat here that I’m terrible at tracking my sources because I’ve been sporadically reading up on this stuff for so long now so I’m very much thinking about what I’ve read over the years and googling for things that look useful in the vein of my osmosis’d knowledge, and I'm also neither medical or science inclined so there's very probably plenty of other and better sources out there. But hopefully it’s still a useful overview for you to start from.

So one of the first things I was taught after I was diagnosed was the glycemic index. If you’re not familiar with that, it’s worth going straight to the source which is a team in my home city who have a big database of glycemic values. A lot of it is fairly common sense stuff ie. sugar and refined carbs digest faster so your blood sugar spikes and minimal processing of ingredients or adding fat and protein will usually lower those spikes, but sometimes GI values can be unexpected so it’s worth getting familiar with if you aren’t. There’s a billion books out there about GI, some of which I’ve found useful but nothing has ever really said anything I didn’t already know straight from the research team's website. I haven't needed to really use the website much in years though so if you still have questions or would like me to browse some of the more recently published books to make some recs, just say the word.

I was also initially advised not only that big spikes can worsen resistance but also to eat six small meals a day to help keep blood sugar spikes down even further as if I was already diabetic, but that seems to be less and less the advice these days. Now I see more people either claiming or investigating that eating less frequently is better for insulin resistance because the less insulin we have constantly circling, the easier it is for that resistance to sort of calm down or at least not progress. MedDiet + skipping breakfast (actual paper also linked from the article), is interesting food for thought given the emerging claims that intermittent fasting might improve insulin resistance (or it might not! It might make things worse! It might screw with hormones which might influence insulin or vice versa! I’ve seen plenty of disagreement there and little serious data yet.) Grazing vs. Two Meals for Insulin Resistance is not academic but also a good summary of stuff I’ve heard from varying quarters. I've also seen some suggestions I can't source right now that loading more calories into breakfast than anywhere else is good for insulin resistance, and that if you do skip a meal it should be dinner.

I personally don’t find GI alone useful, even in the context of knowing to eat more plant foods and such. It certainly contributes to positive results for me, but the many dieticians who have advised me to eat ‘a low GI diet’ and gave me little further advice proved… frustrating, shall we say. And people who are really strict about this end up cutting out for instance certain fruit and vegetables while freely being able to eat pizza, so it’s definitely just an additional info point and not a useful overall eating pattern to my mind. Good building block though.

After lots of trial and error and reading and failed interactions with the medical professionals, I’ve mostly settled in on the Mediterranean Diet as the focus of what I look at now. In part because I’d agree with recessional that it seems to have the biggest evidence based consensus that it’s helpful and certainly that it’s also unlikely to do me unexpected harm, in as much as anything seems to have consensus. And in part because of seeing stuff like this:
Effects of MedDiet on need for drugs in newly diagnosed type 2 patients - can’t find a free full source for something like this, but the abstract has a good example of the kind of comparison stats that now feel like old news to me when comparing a high (healthy) fat MedDiet vs. low fat diet on insulin/sugar
What’s behind Mediterranean diet and lower cardiovascular risk - full paper linked at the bottom; this is cardio focused but I find the insulin component interesting and the timeframe mentioned for some of the people followed is encouraging, plus it’s super recent. If you do dig further into MedDiet at all, you’ll find an overwhelming amount of cardio focus but often with secondary usefulness for insulin and other health issues.
Dietary Polyphenols, Mediterranean diet, Prediabetes, and Type 2 Diabetes
MedDiet may lower risk of developing metabolic syndrome

If you’re not familiar with the actual definition of the Mediterranean Diet, Mayo Clinic has a decent basics guide. If you’re reading Pollan and such then most of this isn’t going to be ground breaking to you, it’s just a slightly more specific version of eating minimally processed and mostly plants. In terms of evaluating research, the specifics of the diet can vary a lot from study to study even though they all list ‘Mediterranean Diet’ as if it means just one thing - I’ve found this a useful literature review to get some basic ranges of things. Diet in the Prevention and Control of Obesity, Insulin Res. And Type 2 is also interesting, and though it doesn’t mention MedDiet the various recommended percents and ratios in the diet are basically the same though MedDiet is perhaps more specifically lower with saturated fat. So there’s more than one way to skin this particular cat for sure.

One thing I do find though is that if I’m mostly cooking from scratch with 5-7+ servings of fruit/vege is that my fat and protein ratios are easily way too low for MedDiet. I can’t put my finger on specific sources right now but I know I’ve read (and my personal experience backs) that going to lower carb/higher fat and protein within the typical ranges of the MedDiet may be better for insulin resistance. I personally aim for around 45% carbohydrates which is the bottom of most ranges and certainly going below typical ranges with something like keto might worsen insulin resistance - proper study also linked from the bottom of this one. I personally wonder if, in this vein, eating less frequently improves resistance because less insulin means less stress on the system and if the usefulness of the MedDiet more specifically is all this nuts and oils and legumes keep the fat and protein ratios higher than just broadly eating plant based or whole foods, but I can’t put my finger on useful sources for that or remember if that’s just me hypothesising or actually having read that somewhere at some point. I personally get decent fat and protein ratios by mostly getting my carbs from fruit and vege and treating wholegrains the same way I treat meat ie. not having them every meal and ideally max 1-2 servings a day. But I also don’t eat gluten or dairy or as many legumes as I’d like for IBS type reasons so my macro ratios may easily not be anyone else’s macro ratios and more grains might be just fine for other people (especially if not aiming for the lower carb ranges), plus the studies certainly seem to assume people eat more of them than I do. If you're interested in this bit I do know I've seen TedTalks and the like lately more in the vein of how I eat re: grains and protein, if nothing else, but that's not necessarily the sort of sources you're looking for.

You’ll also see lots of ‘MedDiet is good because it’s low in red meat’ claims around if you look, but that may not be necessary for health as long as your meat is well chosen. Not worrying as much about that component of the MedDiet might also be useful for insulin by helping to keep overall carbs and GI down.

People have often waxed poetic about high quantities of olive oil and polyphenols with the MedDiet, but this also fascinates me on the oil benefits front: Good Fats vs Bad Fats: Comparison of Fatty Acids in the Promotion of Insulin Resistance, Inflammation and Obesity. Total anecdata here, but I went on a coconut oil kick a few years ago for a bit largely to replace dairy in certain deserts and surprise weight drops started happening. I didn’t get more blood tests at that time to confirm it, but historically my weight only shifts down when I’m making a sustained and higher than usual improvement to my insulin resistance. I’m sure many fad followers would argue that makes the coconut oil a magic bullet food or something, but I wonder if something like this might better explain it - along with more definitely how oil in everything would have been lowering the glycemic index of my desserts, and displacing carbs in my overall calories.

In terms of specifically obesity and does it drive insulin resistance or does resistance cause obesity and all that fun stuff, I’m mostly still at sea. I feel like opinion changes on causes and risks more often than anything else I read, and a more science inclined person than me could probably sift through all that better but I’ve mostly given up. It definitely seems bad for us, even if only from a likely to progress to diabetes standpoint. Or possibly resistance starts because something else is wrong (beyond just a high GI diet) that we don't understand. I do know there’s plenty of higher weight people without insulin resistance, and lower weight people with hidden insulin resistance. I have personally continued to gain weight on the above diet, mostly because I am a fallible human with too many health problems to juggle and I can’t strictly adhere to the above eating suggestions all the time. When I can do it 90% of the time for an extended stretch, weight comes off without me doing anything else to shift it. But even eating like that some of the time with occasional bouts of being really good about it has reduced my insulin resistance from borderline prediabetic to only barely resistant, while my weight has still doubled since my resistance was first diagnosed. So I'm inclined to think it's definitely not as simple as or all about losing weight.

One other thing I would mention is metformin. This is super recent and fascinating, given most things don’t work long term for weight loss. It’s also a magic bullet for weight + insulin resistance in my personal experience. I could eat or exercise as much or as little and as well or as badly as I wanted and still drop weight and improve my test results, but I couldn’t tolerate the side effects on my digestion (which is sensitive at the best of times, though) so it made me really sick in other ways. So if you do have or develop insulin resistance and metformin is suggested to you, there’s definite pros and cons. But I think I remember you talking about gut issues before so you might want to be really careful with it. The slow release version seems to help a lot of people avoid side effects, but my gut is still a special snowflake on that version of it so I gave up.

I've also tried to keep this succinct, but, well, it's long and heavily sprinkled with personal opinion. If there's anything you want me to elaborate on or doesn't make sense though, just ask. I am happy to talk about this stuff till the cows come home!

Hmm, I'll be subscribing to the answers to this post -- very good question.

WILD RIDE FROM START TO FINISH

I left this tab open to see people's replies, which I'm finding very helpful--including this one. *fistbumps*, perhaps? I can't keep weight on despite trying to gain 2 kg at times, and currently I have both immediate stress and the processing of long-term (cPTSD) stress. *shrugs* I too walk a lot, FWIW.

I think the "take a break" stuff is partly to keep people from injuring themselves and not noticing. If they can't distinguish muscle-is-tired pain from actual-injury pain, then going multiple days in a row may result in lasting damage. (It may not! But it may.)

*fistbumps* I just want to donate blood!

I hear you.

Saw this and thought of you:

https://www.frontiersin.org/articles/10.3389/fnut.2019.00066/full

FRUIT IS SAFE OKAY.

LOLOLOLOL.

I just posted on body composition changes due to a month and a half on crutches, BTW.

Not sure if you're still looking, but this was a fascinating and actually scientific (Randomized, controlled research) look at people eating super processed v unprocessed food -- its one of the most scientific studies I've seen, since they tracked stuff like hormone changes and blood glucose levels and other metabolic changes quite closely

https://www.npr.org/sections/thesalt/2019/05/16/723693839/its-not-just-salt-sugar-fat-study-finds-ultra-processed-foods-drive-weight-gain

https://www.nytimes.com/2019/05/16/well/eat/why-eating-processed-foods-might-make-you-fat.html

"The perpetual diet wars between factions promoting low-carbohydrate, keto, paleo, high-protein, low-fat, plant-based, vegan, and a seemingly endless list of other diets have led to substantial public confusion and mistrust in nutrition science" https://www.cell.com/cell-metabolism/fulltext/S1550-4131(19)30248-7

"LANDMARK findings that food processing - not fat, sugar, salt, carbs, or even fiber - drive over-consumption, while minimally processed, phenolic-rich foods drive gradual weight loss. Likely starving vs. nourishing the microbiome too." https://twitter.com/Dmozaffarian/status/1129120688177131522 (Dean of school of nutrition at Tufts)

Everyone is focused on "it makes you fatter" &c &c but I was more intrigued by how people on the ultraprocessed diet ate more, felt less satisfied, and there were apparent significant impacts on their health.

Those look really interesting, thanks!

I tend to think anything that separates "fruit" from "vegetables" is based on social goals and not science. The site doesn't define either of them, although it does have subgroups of vegetables.

As far as I can sort out, mushrooms are entirely outside of any of their food groups.

They list mushrooms as vegetables here - or do you mean that scientists don't consider mushrooms vegetables? And are you referring to problems like "tomatoes are really a fruit"?

As a popular history writer, I tend to distinguish between research and presenting research results to the public. But then the question becomes: Did the USDA offer lay definitions because that was the easiest way to communicate with the public, or because they were working from bad research? I do notice that they have this page, so they seem to be aware that definitions can vary, depending on which group is using the word.

A few areas of nutrition and health science that I've read about recently:

Tim Spector's research on the gut microbiome and its impacts on health (if what he says is true, it's probably contributing to the results mentioned above about the negative effects of processed food): The Diet Myth is his book; there are excerpt/articles and videos like "What Role Does our Microbiome Play in a Healthy Diet?" from the Royal Institute floating around. Apparently he's been doing this research for some time, but it probably still counts as 'new' since it's not widely known or accepted by doctors and science journalists...? To promote the health of one's own gut microbiome with diet, he advises maximizing diversity with different foods from as many sources as possible, as well as emphasizing fibers, fermented foods, and polyphenols.

A few months ago I saw a TED talk (Segal, "What is the best diet for humans?") about this 2015 study, Personalized Nutrition by Prediction of Glycemic Responses, which found that the "ideal diet" actually varies tremendously from person to person because which foods cause blood glucose spikes varies from person to person. "Glycemic Index" is supposed to tell you how much of a blood glucose spike an individual food will produce (hence you'll get things like 'But ACTUALLY white rice has a higher glycemic index than [carb-based dessert food]'), but it's based on average values that aren't guaranteed to hold true for any individual.

I recently read a short recommendation for The Salt Fix, a 2017 book by a cardiologist claiming that salt has been erroneously blamed for high blood pressure without other factors being adequately controlled, and that a diet too low in salt is more dangerous to the health than a diet with more salt than your body needs. I gather there isn't really enough research to support this position right now and that it all hinges on arguing about how studies have been interpreted, so I doubt this book is going to provide me with a definitive answer, but I intend to read it anyway, not least because I'm always suspicious of 'accepted wisdom' medical advice about which doctors are as passionate as they are about the salt one.

Edited ()) 2019-05-22 21:10 (UTC)

Ah! I didn't see the fold-out charts, which don't display properly on my browser. I did a ctrl-f search for mushrooms but got no results because they don't show if you haven't clicked on the "+" markers.

And yeah, I meant tomatoes, bell peppers, olives, cucumbers... there aren't many that go the other way, but the casual classification seems to be based on sweetness rather than any other nutritional concerns.

I'm twitchy about any nutrition site that has a page called "All about the vegetable group" that doesn't tell you how it's deciding what a vegetable is. They've got no criteria for helping people decide what a fruit/vegetable not on the list falls under. (Lychee: Probably fruit. Jujube: Not certain; they're sweet-ish but no more so than cucumbers. Fruit-ish, though. Bamboo shoots: Probably vegetable; starchy? Or other? Mung bean sprouts: Vegetables? Or in the separate category that beans go in?)

It's not that I think the page/system is founded on bad science, it's that whatever science it's using is opaque to the reader.

- Do we actually know anything about nutrition, given the every-five-year swings between "eggs are cardioprotective/eggs are a heart attack on a plate," "fat is the Devil/carbs are the Devil," etc? If so, what is it and how do we know it?

Actual scientists are not making those swings, the media is in its chronic churn. The data says something like "a reasonable amount of eggs, in moderation, are probably good for you, but eating too many is probably bad for you" and "all humans need fat/carbs/protein in reasonable proportions, which no doubt vary according to genes and lifestyle in ways that we're still working out".

Can you rec some books or articles that go into depth on those topics, such as what is meant by "a reasonable amount," "in moderation," "in reasonable proportions," and "too many?"

You've raised an important point I've never thought about: How are those borderline cases classified nutritionally? At the very least, the USDA should have a page listing how each food is classified for nutritional purposes. For example, is a gluten-free "grain" like quinoa nutritionally similar to actual grains?

I know that they've got more technical material buried in that website, but they need to put something about this on their front pages.

Not a one. Though I can say that we're increasingly finding that each person's ideal diet - from caloric intake to specific proportions of nutrients, to the actual foods that will raise blood sugar (etc) varies considerably, probably due to genetics + microbiome but who knows.

So honestly, I'd just eat what I enjoy and maybe a salad now and then.

Is the conclusion I drew from a long article in The Economist
https://www.1843magazine.com/features/death-of-the-calorie
By Peter Wilson
DEATH OF THE CALORIE

The history of the calorie as a measurement of food value is checkered and confusing, and wildly inconsistent.

Waaaaaaait what is the childhood traumatic stress and electrolytes thing? (I get that there is going to be more noise than signal, but... this seems relevant to my own situation.)

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Debunking food, fat, and fitness myths

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Re: ObOffTopicDigression

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And, also our measurement basis is imprecise

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