An Apple a Day Does Surprisingly Little?

How did apples get to be the standard bearer for all that is good and healthy? In terms of nutrient per calorie, they’re not that good. 1 cup has 65 calories, 3 grams of fiber (12% RDA), and 5.7 mg vitamin C (10% RDA), and very small amounts of a wide range of other nutrients. Pears are just slightly better: 1 cup has 81 calories, 4g fiber, 5.7 mg vitamin C, and enough potassium to be noticeable.  Meanwhile the same volume of grapes, so long derided as nature’s candy, have 104 calories, 1.4g fiber, 16.3 mg vitamin C, 22 mcg potassium.  Almost everything apples or pears have trace amounts of, grapes have slightly more of.

Wasting their lives
Wasting their lives?

I wonder how much of this is because of the skin:pulp ratio.  Produce skin tends to have a lot the bulk of the vitamins*.  Plus grapes are more colorful, and color intensity is a shockingly good proxy for nutritional value in produce.

I also wonder how apples got such a sterling reputation without the benefit of a good marketing firm.   My best guess is that they grow further north than most fruit and keep for much longer, and established cultural supremacy back when produce was scarce and fruit did not regularly fly.

Full disclosure: I was originally going to compare apples to iceberg lettuce, which I had previously seen described as nutritionally vacuous but easy to ship.  But when I looked it up I discovered iceberg lettuce actually has a pretty good nutritional profile.  1 cup has 10 calories, 1 g fiber, 2.0 mg vitamin C, and 22.0 mcg potassium (22% RDA), and trace amounts of other stuff, which makes it strictly better than apples on a per calorie basis.

While we are at it: spinach does not have that much iron.  It has a number of other vitamins and is very good for you, but the original reputation for iron-richness came from some guy putting the decimal point in the wrong place (source: some guy at a party 6 years ago).  In fact the oxalates in spinach bind iron, making it harder to absorb.

Apples aren’t bad for you.  If you want an apple, eat an apple.  But if don’t want an apple and are trying to cajole yourself into it to make doctors keep their distance, consider grapes instead.

*Also the pesticides.

HAES post-check

A chief contention of Health At Every Size (Linda Bacon) is that human beings can’t lose weight, so even if it would optimal for them to weigh less, there’s nothing to be done about it.  Is this true?  It’s hard to answer, because the question isn’t very well defined.  Bacon admits there are things human beings can do to gain weight, and when they stop doing them, they sometimes lose weight.  So if you’re doing those things, you probably can lose weight.  And that people have a set range they can move around in healthily, based on diet and exercise, so if you’re at the top of your range now you could lose 20 pounds and still be okay.

On page 143, Bacon very strongly implies that twins maintain the same body weight even when they have very different activity levels, so weight is controlled by genetics.  The studies she cites do show that when activity and diet is held constant, two unrelated people will have different health metrics.  They also show that when two identical twins have different activity levels or diets, they will have different health metrics (including weight).  Oh, and the combined sample size of both studies together is 35 sets of twins.  This is where I started to get angry.  I get using weak studies that strongly support your hypothesis.  I get misleading people about what a study stays to support your hypothesis.  But doing both is just…argh.  I supported HAES.  The actual prescriptions for food are basically the Michael Pollan diet (eat food, mostly plants), and motivation to retrain yourself to like real food rather than hyperprocessed crap.  Those goals are good.  Those goals are good even if they lead to weight gain, because under most circumstances produce is good for you and cheetos are not (although not all- this Captain Awkward post is full of people for whom carrots trigger intense digestive distress but hamburgers are safe and nurturing.  I used to live off of pasta because anything else felt like eating death.)

I did check Bacon’s sources on the claim that people who lose dramatic amounts of weight tend to gain it back within 5 years.  That appears to be true, at least in the studies she cited.  And yet, she also cited studies showing that activity level affects weight.  My explanation is that losing weight is not a thing you do.  Your diet and activity level translate to a weight or body fat percentage*.  If your current weight is different than that, it will move towards it.  If you change your behavior, you will move towards the new translated weight.  The translation appears to be a combination of genetics and perhaps past experience (she claims loss-and-regain cycles increase the set point.  I’ve read that a lot of places, but at this point I neither trust her nor have the heart to investigate).

So how do my current views compare to those I held before reading HAES?

Exercise- still good for you.

Human diversity- still vast.

Impervious of weight to diet and exercise- depends a lot on what you mean.  I will never look like Keira Knightley, but I will probably lose fat if I exercise more.  Which I have just started to do after ceasing for a very long time because I was recovering from surgery, and will pause again when I have my next surgery, because the health harms outweighed the benefits.  Fat is a proxy for health, but not the only measure of it.

Large amounts of fat are quite bad for you, but it’s unclear where that effect kicks in.  The American aesthetic ideal is much lower that the healthy weight cut off, and may be actively unhealthy. In the normal range, diet and exercise have bigger health impacts than fat.

Our food supply is definitely fucked.

Fat people still don’t deserve to be shamed, especially under the guise of for their health.  First because no one deserves to be shamed, but especially because shame is super bad for your health.  It is intrinsically bad and it keeps people from seeking medical care, for both things related and unrelated to their fat.  Stop doing it.  People owe you neither their health nor their attractiveness.

*Weirdly, in my case it appears to be weight.  I’ve had a shockingly consistent weight despite large changes in activity level and muscle mass.

The Limits of Metrics

For a long time now I’ve been trying to describe a hesitation I’ve had around EA.  Outcome metrics are great.  Outcome metrics are a huge improvement over “but look how much money we spent.” and “have you seen how sad this child is?“.  And yet.  My original stated concern was that over-reliance on metrics would drive us to focus on easy-to-measure outcomes over equally more* important hard-to-measure outcomes, or on known outcomes over more important unknown outcomes.*

Now I have a better analogy.  Metrics are like nutritional labeling.  Nutritional labeling is great when you want to decide between cheetos and soylent, or between soylent, mealsquares, and any one of their homebrew competitors.**  But suppose I set a fiber quota for myself.  The ideal way to do that would be to eat a variety of fruit, vegetables, beans, and nuts throughout the day, but that is super hard to keep track of.   I either have to eat in exact serving sizes (forcing the continuous variable of hunger to the granular treatment of serving size) or calculate exactly how much I ate after the fact (a pain in the ass and/or impossible), and then look up how much fiber is in the food (ignoring any natural variation), write it down, total it up… and if it’s midnight and I’m short, eat a ton more food I may not want.  Or I can pour a bunch of psyllium husks in a glass in the morning, check “eat fiber” off my todo list, and eat HoHos for the rest of the day.

Obviously the first choice is better overall, even if I ultimately end up with less fiber. But it is much harder to measure, in part because the benefits accrue over a wide variety of nutrients, whereas the psyllium and HoHos diet produces one big shiny number to trumpet in brochures.  I think this is a problem in charity too.  The Ugandan girls-club study I looked at last week had some outcomes that were both easy to measure and to value (spending), easy to measure but hard to estimate the value of (delayed marriage and childbirth), and kind of fuzzy to measure and of unclear value (age at which they do marry, as measured by proxy “when would you like to get married”).  Luckily for that project the increase in girls’ income per unit NGO spending was almost as high as it was for pure vocational training, plus it had these social benefits, but suppose it had been 75% as good?  Half as good?  10% as good?  What is the cut off for being better than pure vocational training.

I’m solving this problem in my nutritional life by drinking a full serving of vitaminized protein powder*** mixed with chia seeds every day, plus whatever the hell I feel like eating.   The almost-food frees up my stomach and brain to figure out what I especially need and seek that out, without fear I’m letting some other deficiency fester.  This is startlingly similar to Holden Karnofsky’s (co-founder of GiveWell) suggestion that westerners focus on the problems of the 3rd world they are in a good position to fix (e.g. malaria), and let the locals do the rest.   So I guess Effective Altruism has addressed this problem, it’s just that it addressed it by limiting itself, which is not the most emotionally satisfying answer but is something the world could do with more of.

BONUS FACT: EA and soylent have both found their home primarily with the rationalist community, and my rationalist friends (all of whom I met through EA) are simultaneously the most likely of anyone I know to drink soylent and to host communal dinners with secular grace.

*E.g. Food aid to the third world looks great measured by “people who stop starving in the short term.”  We know now that this destroyed the local farming economy and left entire regions either starving or in ongoing dependence on 1st world aid.

**Of these, mealsquares have been the clear winner among my friends.

***Not quite the same as soylent because it lacks the fat, carbs, and fiber to be a meal replacement.  This presents two slightly different problems.  The lack of fat and sugar I feel fully prepared to make up for in the rest of my diet.  But nutrients are digested differently depending on what other nutrients they are in proximity to.  The chia seeds are attempt to get the benefits of protein x fiber.

Fiber: the Mr. Rogers of nutrition

I have consciously decided to let the arguments for high protein diets pass me by, despite how convincing some of the research and underlying mechanistic claims sound.  Humans have been cycling through high -protien, -fat, and -carb diets since we developed enough of a surplus to choose, and I’m pretty sure if any of them were that superior to the others it wouldn’t have been supplanted.  I would say “everything in moderation”, but that is just a zen way of saying “Eat the correct amount.  Idiot.” which I don’t think is very helpful.

HAES brings up a more constructive suggestion: eat fiber.  Fiber* is usually left out of the macronutrient triumvirate, but so is water, and water is extremely useful.  Off the top of my head: Fiber has the advantage of being natural**, because our ancestral foods had much more fiber than our current ones, yet its lack of calories is well suited to our current, couch-based, lifestyle.  It evens out digestion of other nutrients, reducing the destructive sugar/insulin boom and bust cycle.  It simultaneously treats diarrhea and constipation (if you drink enough water, which you should anyway).  Have you ever wished you could eat a good thing and have it cancel out a bad thing?

mitch-hedberg-onion-ring

Well, that might actually be true if the good thing is fiber, and the bad thing is not cocaine.

Here is where I meant to track down all the good things HAES says about fiber, but when I read it more carefully.  I realized most of what it was praising was fruit, with the implication that fiber was the reason fruit is beneficial.  The one actual fiber claim is that high-glyemic diets increase the risk of type 2 diabetes unless the diet is also high in fiber (five sources, all of which say nice things about fiber, one of which is actually about type 2 diabetes.  The paper did conclude that fiber fights type 2 diabetes, but it was a post-hoc survey, which is a weak methodology).  However, those other four sources also say pretty good things about fiber, just not the one the book claims they did.  I think we are all on board with “fruit and whole grains” > “potato chips and soda”, although I’m severely disappointed that this of all books is backing that up with data on weight loss, rather than actual health outcomes.

But Dr. Wikipedia has many very specific nice things to say about fiber, and it cites much more relevant sources.  Fiber increases micronutrient absorption (a little).  Fiber increases nutrient absorption (more).  Fiber fights inflammation.  Basically, it does everything good and nothing bad.  So while HAES didn’t lay out its case properly, fiber is definitely good, and I look forward to finding out who takes this too far and what the negative effects are.

*Definition of fiber varies a little from institution to institution, so for clarity: I am defining fiber as carbohydrates that are not broken down for energy in the human body.  It’s worth noting that there are two contributors to whether an organism can digest food: its own enzymes, and the bacteria in its digestive track.  Termites can’t naturally digest wood, but they house a bacteria that can.

**It’s easy to oversell “naturalness”, but when you have a mission critical system made of complex legacy code no one understands, sticking close to its original environment is a good default strategy.

Bariatric Surgery

I had a pretty poor opinion of weight loss surgery already, but Health At Every Size all but says any doctor recommending it should lose their license for malpractice.  That claim seems worth investigating.  Luckily, she cites her sources.

First, I feel it’s important to note that bariatric is medical Greek for “obesity related medicine.”  I’m already not thrilled with that because I think excess fat is a symptom of health problems, but rarely a health problem in and of itself.  “Bariatric surgery” is often sold as something that is fixing a problem, the way an appendectomy fixes appendicitis, but it is at best undoing the damage of something else that is making you fat.

That said, let’s start with the immediate death rate.  HAES quotes a study as reporting a 4.6% death rate within the year: what it doesn’t say is that that study was done on Medicare recipients, meaning they were older than 65 or disabled.    Moreover, the 4.6% number is based on death from any cause, not what would be expected above and beyond what is normal for patients’ age and health.  Controlling for age, sex, and likelihood they would have died anyway* the researchers found that surgery increased your risk of death in the 90 days after surgery by somewhere between 90% and 200% (=3 times as likely to die), depending on which demographic you were in.  Inexperienced surgeons make this worse (which they do not back out of their model).  This is not just the stress of surgery: that’s twice the death rate following coronary revascularization or hip replacement, neither of which are minor.

HAES cites another study, published in JAMA as reporting a 6.4% four-year death rate.  This study has a number of problems.  Its only control was matched for age- and sex- but not health status.  A lot of the deaths stem from heart disease, which could plausibly be caused by being fat or having been fat, which is not a case against weight loss surgery.  Worse, that was the death rate only among people considered “at risk” enough to justify four years of follow ups.  The article doesn’t explain what qualified someone as “at risk”, but rarely does that risk mean “at risk of living too long”.  HAES cites a blogger who cites the study as demonstrating a 250%-360% increase in mortality over four years, relative to age- and BMI- matched controls, but I don’t see that anywhere in the original paper.

Meanwhile, the American Society for Metabolic and Bariatric Surgery aka “the people doing the surgeries” is happy to report a mere 0.2%-0.5% mortality rate after the first month of gastric bypass surgery.

That’s everything the book cites on mortality, which I found unsatisfying, so I turned to Dr. Google.  This Swedish study actually bothered to match controls (although surgery was not assigned at random, introducing the possibility that the surgical patients varied on a factor they didn’t think of) and found a 30% reduction in death over 10 years.

But I hate it when people act like death is the only bad thing that could ever happen to you.  What about people who don’t die, but do suffer for the surgery?  HAES cites six studies showing long term nutritional deficiency.  Of the five I was able to find online, all showed serious deficencies and none had a control.  Interestingly they all found a vitamin D deficiency, when vitamin D is primarily produced by your skin in response to sunlight, unless you live in Seattle, in which case you mostly get it through supplements.  Either way, food is not a major source of it, and if bariatric surgery effects vitamin D levels (which these studies have not demonstrated) I am extremely curious as to why.  Given the current controversy as to the efficacy of vitamins even in people with normal stomachs, it’s not clear how much this issue could be fixed with supplementation.

Every study I’ve read agrees that people lose substantial weight after surgery and then gain some of it back, I’m not even bothering looking for citations for this.

CONCLUSION: bariatric surgery has severe risks.  These may be partially compensated for by a skilled surgeon and good nutritional technique.  For extremely obese patients the benefits may outweigh the risks.  We don’t know where the cut off is for “fat enough to benefit.”  The strongest piece of evidence against bariatric surgery is that no one has done the fairly obvious studies that would conclusively demonstrate their effectiveness.

Some of the benefits probably stem from societal approval rather than genuine health issues, and the long term fix for that is for society to stop shaming people for their weight.  Another part of the benefit may be a forcing function, i.e. if patients ate like they’d had the surgery they’d lose weight whether or not they actually had it.  For an individual living in the society they live in and who has already tried dietary changes, this is sad but irrelevant to the decision.

I’m really uncomfortable with this conclusion.  It doesn’t fit my prior model, and I prefer the tribal affiliation of strong weight loss surgery opponents to strong weight loss surgery advocates.  I consider the evidence I’m basing this on somewhat iffy,  but in all honesty if it had come out the way I expected I would be fine with it.  I’m also pretty disappointed in HAES for so blatantly misrepresenting the evidence.

*Risk of death was calculated using the  Charlson Comorbidity Index.   I have no idea if that is a good model, but it appears to be standard.  This doesn’t prevent the researchers from being wrong but it does mean they’re probably not being deliberately manipulative.

Poverty, Medicine, and Research

John: http://gap.hks.harvard.edu/women%E2%80%99s-empowerment-action-evidence-randomized-control-trial-africa
[Women’s Empowerment in Action: Evidence from a Randomized Control Trial in Africa]
Me: That’s awesome. Wait, why are they jumping between percentage points and absolute percentages? And they don’t give the absolute numbers at all.*
John: http://www.ucl.ac.uk/~uctpimr/research/ELA.pdf
Me: Sweet. Wait, so they plopped some afterschool clubs down and then measured outcomes for girls that attended them? That’s a hell of a confound.**
Paper: Nope, this is an RCT, and we compared both attendees and non-attendees (will overestimate impact due to confounds, but miss any spillover affects on non-attendees) and treatment communities with control communities (will underestimate impact because only 20% of girls attended the club, will catch spillover effects).
Me: But mobility is high, what if girls leave the area?
Paper: we track them. Plus attendees, members of treatment communities, and members of control communities had similar attrition rates.
Me: I’m still distraught you’re only giving rates of change, not absolute numbers.
Paper: Jesus Christ, not everyone loves numbers as much as you. The numbers are in the appendix.
Me: This looks like you made it worse.
Paper: Maybe it would help if you read the part that explains how to read the numbers.
Me: Your sexual health knowledge test includes questions like “A woman cannot catch HIV while on her period. T/F”. That’s the opposite of true.
Paper: You see why we’re concerned.
Me: HA! You said you calculated based on living in a treatment area, not participation, but table 2 is contingent on participation.
Paper: Table 2 describes duration and intensity of club attendance.
Me: Fine. Your study was perfect and its results are amazing. But you said Africa and the study takes place entirely in Uganda and treating Africa as a uniform mass is racist.  Why don’t you just talk about your tiger prevention efficacy?

africa

The paper graciously conceded my last point, but it knew my heart wasn’t in it. There is no end to the number of follow up studies one can suggest, but this is as good as a single study can be, and I accepted their conclusions. Founding afterschool clubs for girls in Uganda, with a mix of social activities and vocational, and health education, has pretty amazing results. $17.90 US (I know the exact number because the paper specifies it, which I love) spent on a girl translates to an additional $1.70 in monthly spending, almost a 50% increase (they tracked spending rather than earnings because self-employment earnings tend to be feast or famine. Employment also went up significantly), and a decrease in rape and child bearing. That means the program pays for itself in less than a year, and they get some additional benefits on the side. And to the researchers’ credit, the abstract trumpeted the less impressive community-wide numbers, when they could just as easily have used the confounded but shiny attendee numbers.

I mention this for two reasons. One: someone found a way to improve the bodily autonomy and earnings of African young women, basically for free. That’s neat. Two, I read this paper the morning after spending hours on a HAES post (which you may or may not ever read because wordpress ate it, thank you very much. WordPress ate this one halfway through too, so what you read is a cliff’s notes version of my original Socratic dialogue). The HAES post was enormously frustrating, because of the two claims I investigated, I found one (that cyclic dieting, rather than current weight, increases blood pressure) to be pretty misprepresentative of the data, and the other (high blood pressure hurts thin people more than fat people) pretty well supported…for a medical claim. By which I meant the evidence came from either retrospective studies (too many confounds to contemplate) or rats specifically bred to have the physical fitness of an aging Tony Soprano. That is genuinely good for medical research, and that fact is really frightening given how much is riding on getting the correct answer.

So when I read this paper, and see the study is well designed, they explain their modeling in a way an educated non-expert can understand, and they refuted every one of my criticisms, I felt a kind of relief. I’m not quite ready to say “trust the experts”, but at least I didn’t spend two hours tracking down reasons to not trust them

*If something goes from 10% to 20%, that’s an increase of 100% but only 10 percentage points. Switching between the two and failing to give the absolute percentages is a common trick for making data look more impressive than it is.

**Confounding variable, i.e. something that varies between your control and treatment group that is not the thing you are studying, and affects outcomes. The most popular confounding variable is time, e.g.

Pirate_Global_Warming_Graph
But here I’m worried about motivation: girls who show up to a club to learn entrepreneurial and life skills are probably more likely to start businesses and delay marriage than those that don’t attend,

Leptin: Catching Chemicals

Leptn is often considered the anti-ghrelin.    It is produced by fat cells to say “I exist and am full, you do not need to feed me.”  Animals with their leptin gene knocked out grow enormously fat.  This is a perfectly lovely story that can be conclusively proven by a picture of a fat rat.

Figure2diabetes
Bring me Solo and the wookie

If you do not find this story compelling, please consider that I also have a photo of a fat mouse.

Well, if it isn't Lone Star. And his sidekick, Puke
Well, if it isn’t Lone Star. And his sidekick, Puke

Are you convinced yet?  Look, I know last week I said all hormones are almost fractally complicated and anyone who says they completely understand one is lying, but that entry forever to write (thanks for publishing that a week early, wordpress), and this entry has pictures of obese rodents.  Surely you believe the rodents?

Original source: http://commons.wikimedia.org/wiki/File:Big_Fat_Red_Cat.jpg
If no, would a cat be sufficient?

*sigh* I’ve created a monster.

Like ghrelin, leptin is important to fetal lung development because, and I quote, “I don’t know stop asking me.”  Leptin is also produced by the ovaries, skeletal muscle, stomach (some cells produce both ghrelin and leptin), mammary epithelial cells, bone marrow, pituitary, liver, and of course adipose tissue.

Leptin stimulates ovulation and sperm production, which makes some evolutionary sense: getting pregnant when you don’t have the resources to carry it to term in a healthy way is extremely costly (men have to be nearly dying before they stop producing sperm entirely, but levels can drop incompletely before then).  This doesn’t explain why the ovaries (but not testicles) produce leptin, since they don’t have any independent information about fat stores.  This may be an example of an override (in which the ovaries decide they want a baby even though the rest of the body doesn’t believe it has enough fat), but the fact that I can come up with a clever anthropomorphization does not make an explanation legitimate.  You can sort of see why leptin facilitates the onset of puberty, since puberty takes a lot of energy.

What you can’t see is why, despite everything we know about pregnancy and eating, the placenta produces leptin. Excess amounts appear to cause hyperemesis gravidarum (extreme morning sickness aka Kate Middleton’s one weakness).

katemiddleton

High amounts of leptin appear to be good for your brain.  Just so story: brains are extraordinarily expensive, so if you don’t have sufficient savings your body turns on the dimmer switch.  They also have a long term protective effect against Alzheimers.  On the other hand, high levels of leptin alter the immune system in a way that encourages artery hardening.  I am way more afraid of living with Alzheimers than I am of dying of a heart attack, so I will count this as one point for fat.

Leptin’s overall effect on the immune system is complicated.  Leptin is an inflammatory agent, possibly to prevent damage from overreating as your body suddenly tries to shove extra calories that won’t fit in the white adipose tissue under the bed and in the coat closet (the organs).  Which may explain why ghrelin is an anti-inflammatory.  Leptin and ghrelin chose opposite powers and color schemes, like an early 90s superhero cartoon.

Or an early 90s cartoon
The safe represents the hypothalamus

Fatness in humans does not appear to be a problem of inadequate leptin production, and more leptin does not make people thinner.  Instead, it appears that the brains of obese individuals are less sensitive to leptin.  No one knows exactly why, but “crash dieting” is high on the list of suspects.  Two people with identical body compositions but different genes or life history may produce very different amounts of leptin, which means they may require very different behavior to stay the same weight, in ways we do not understand at all.  Which I could have told you before we went on this magical photographic tour of my childhood.  But now we know for sure, plus I learned that fetal lung development is creepily intertwined with food in a way no other organ is.  Let us go forth and use this new knowledge

The Rescue Rangers also want me to play video games.
The Rescue Rangers also want me to play video games.