Comment author: Lumifer 21 January 2015 04:51:27PM 0 points [-]

I don't think that's true, unless we're thinking about "efficiency" in different ways.

I think what the OP means is that conditions which allow rapid population growth are conditions which reduce the natural selection pressure.

An extreme version of this is the observation that if everyone survives and breeds, there is no fitness advantage to any gene and the gene frequencies do not change.

Comment author: c_edwards 21 January 2015 08:59:58PM *  3 points [-]

I'm probably being overly anal here, but this something I work with on a professional basis. Preface: when I'm talking about 'fitness', I mean the (slightly simplified) biological definition of the term, which means "number of offspring you have before you die"

I think what the OP means is that conditions which allow rapid population growth are conditions which reduce the >natural selection pressure.

This doesn't need to be true at all - see below.

An extreme version of this is the observation that if everyone survives and breeds, there is no fitness advantage to >any gene and the gene frequencies do not change.

Also not necessarily true (because "everyone survives and breeds" is very different from "everyone survives and has an identical number of offspring).

Selection occurs due to differences in relative fitness, which can be calculated as (personal fitness)/(average fitness of everyone). If everyone has 2 offspring, everyone has a relative fitness of 1. If we have a good year, and everyone has 3 offspring, we have the same relative fitness.

You and OP seem to be thinking about situations in which some sort of environmental limits on fitness have disappeared, and now everyone is limited by some trait for which there is less/no variation. That's actually a really special situation. Certainly the statement "Some events reduce variation in relative fitness while also increasing average fitness" is true. But so is the statement "Some events increase variation in relative fitness while also increasing average fitness". Any time conditions increase the fitness of above-average fitness individuals, average population growth increases and selection becomes STRONGER. This is something you would definitely expect in organisms for which individuals actively compete for patchy resources - in a good year, the alpha/owner/whatever of a given territory will get most of the increased value of said patch, and individuals who were without territory may not gain anything at all. (it really depends on the situation, though)

Anyways, average fitness and variation in fitness are two largely independent things. "Rapid population growth", or even "nobody dies before breeding" doesn't inherently mean less selection/slower evolution. Sometimes just the opposite (see )

Comment author: Metus 19 January 2015 10:54:51AM 4 points [-]

European countries are way more lenient with workers who do not show up for health reasons. How does the data compare there, are workers more productive on average and sick less often?

Also, what is the unintended side effect of this? Do we open up an evolutionary niche for something even more horrible? Wouldn't it be better to require sick people to wear a face mask like it is usual in some Asian countries?

Comment author: c_edwards 21 January 2015 05:24:56PM *  3 points [-]

Typically with the evolution of pathogens, we see a trade-off between the ability of a pathogen to spread ("virulence") and the ability of the pathogen to keep the host alive (although there's definitely a lot of variation depending on the life history of the pathogen and the behavior of the host). Overall pathogen fitness (for between-host dynamics - it gets more complicated if the pathogen is competing with other pathogens within the host) is based on (virulence) x (number of other hosts that infected host contacts). So increasing host lifespan and increasing virulence both increase pathogen fitness (but, again, usually increasing one decreases the other). This means that we often see pathogens falling into two syndromes:

a) Fast spreaders ("raiders") - because they spread rapidly, there is less selection for them to keep their host in good condition (and so it's better to sacrifice host health to increase spread rate). Alternately, because their host becomes ill rapidly, there is selection for them to be good at spreading. Example would be Ebola.

b) slow spreaders ("farmers") - because they do not spread rapidly, there is selection for them to keep their host in good condition. Alternately, because their host is in good condition for a long time, there is less selection for them to be good at spreading. Extreme versions of this are pathogens that are largely/entirely transmitted vertically (mothers pass pathogen to offspring). Because the host's fitness is a part/all of the pathogen's fitness, there is strong selection for the pathogen to keep the host alive (and even to boost host fitness). A super interesting example of this can be found in the arthropod bacteria , where some Wolbachia species have evolved into mutualistic relationships with hosts. (But because Wolbachia is only passed from mothers to children, many species change the sex ratio of offspring of infected individuals to be all female. Biology is awesome!)

Decreasing the number of people the host is in contact with is effectively decreasing virulence rate. Because the host (sick person) isn't going to be in contact with too many potential hosts (other people), there's a fairly low upper bound on how fit a super virulent/damaging pathogen can be - it's much more effective for the pathogen to maintain host health as much as possible. Typically we expect this to lead to decreased health impacts on the host. Additionally, this would give hosts a longer time to get access to treatment.

tl;dr Decreasing contact rate is likely to lead to evolution of less virulent/harmful pathogens

Comment author: CellBioGuy 20 January 2015 05:05:12AM *  2 points [-]

Rapid population growth decreases the efficiency of purifying selection.

EDIT See below for corrections. Only vaguely true under certain circumstances. Mostly wrong. Was tired and thinking of the wrong metrics.

Comment author: c_edwards 21 January 2015 04:41:38PM 2 points [-]

Rapid population growth decreases the efficiency of purifying selection.

I don't think that's true, unless we're thinking about "efficiency" in different ways.

In general we think of selection in terms of gene frequencies, not raw abundance. Which means that all that is relevant is relative fitness, and if your fitness advantage remains the same, doubling everyone's reproduction rate doesn't change the force of selection.

Unless you're talking about the time until a deleterious, entirely recessive allele goes extinct? Since in that case drift is the only force that will push it from "very rare" to "non-existent", increasing population size will decrease time to extinction of the deleterious recessive allele (drift is faster/stronger in smaller populations).

Comment author: zedzed 20 January 2015 02:57:46PM *  1 point [-]

See also discussion here, in particular, soylent green (unsuitable for OP because hypoglycemia), soylent orange (yay complex carbs!) and ketosoylent (most recently Yudkowsky's Mildly Surprising Super Ketonic Dietary Replacement Fluid: Your Alternative To Healthy Eating.)

Comment author: c_edwards 20 January 2015 03:47:26PM 0 points [-]

I probably should try adding soylent orange to my overall plan. Some part of me is uncomfortable with the idea of meal replacement shakes, but I don't think that's a rational feeling.

The only rational argument against it that I can think of is the same argument against repeating the same meal every day - the lack of diet diversity. RomeoStevens seems to have found no intermediate-term health issues on a mainly-soylent-orange diet, but additionally if I'm using soylent orange as only a part of my diet, I'm still going to have a decent mix of food sources.

Time to dust off the blender.

Comment author: RomeoStevens 26 March 2013 10:55:08PM 4 points [-]

I am lactose intolerant. Lactase is cheap from amazon.

Comment author: c_edwards 20 January 2015 03:41:46PM 0 points [-]

The Lactase is only there because of your lactose intolerance, right? It's not important for any other reason?

Comment author: Vaniver 19 January 2015 10:52:13PM *  5 points [-]

(note that I'm a bit wary of meal-replacement shakes)

So, I suspect MealSquares deserve a mention as having many of the benefits of meal-replacement shakes without of the detriments of it being a shake or being thrown together from uncertain ingredients. They seem to be the best option time-wise (it takes approximately five seconds to open a package and start eating), but are significantly more expensive than a diet based on preparing staples yourself. (If you want to eat just MealSquares, you're looking at ~$10 a day; if you want to eat just rice and beans, you're looking at ~$1 a day.)

Comment author: c_edwards 20 January 2015 03:35:06PM 0 points [-]

Absolutely worth mentioning. They're something I'm interested in looking into, but as you say the pricing is a fair bit higher, and at the moment I'd prefer to keep costs lower.

What I'm seeing is $85 for 6 packs of 2000 calories. Which means $14/day for a person consuming 2000 calories per day. I am a large male with an active metabolism who is attempting to exercise on a regular basis - I haven't counted it up, but I'm probably closer to 3000 calories, which means $20/day. Still great compared to other prepared food options, but not the best option for me right now.

For other people, though, with slightly more expendable income and a desire to get a quick balanced diet in a non-shake form, this is probably a fantastic choice.

Comment author: RomeoStevens 19 January 2015 06:25:37PM 4 points [-]

It sounds like you're using tuna as a staple. Keep in mind that tuna is quite high in mercury. Consumer reports, after measuring the mercury content of some of the common brands, concluded no more than a can a week should be consumed to stay within guidelines on mercury consumption. I'd recommend replacing some of the tuna with herring or salmon, both very low mecury fishes with great omega 3 content.

Comment author: c_edwards 20 January 2015 03:21:22PM 1 point [-]

Thank you! Apparently this is fairly common knowledge (when I mentioned this to several friends they thought it was obvious). But I hadn't been aware, and that could have been very unpleasant.

I'm going to switch "tuna" to "canned salmon" in my post, and I'm trying out canned salmon today. Interestingly, when on sale there's not much difference in price between canned tuna and canned salmon, at least where I live.

Comment author: zedzed 19 January 2015 03:23:26PM 8 points [-]

Let's talk about drugs!

Caffeine's an adenosine antagonist. Now, let's figure out what that means.

Neurons have proteins embedded in their membranes called receptors. Chemicals (e.g. neurotransmitters) can bind to these receptors, which causes stuff to happen. For instance, adenosine is a chemical, and it can bind to receptors in your brain cells, resulting in sleepy behavior.

(Here seems to be the place to mention that this is a vastly oversimplified explanation. Those interested in a technical explanation would do well to check out the appropriate textbook, because I literally just condensed over three chapters of my psychopharmacology textbook in as many sentences.)

Caffeine is an antagonist. Antagonists are able to bind to receptors without causing the stuff to happen. Since the receptors are already bound, the adenosine can't bind to them, meaning the stuff (in this case, sleepy behavior) happens less.

This leads nicely into tolerance. Your body reacts to not-enough-working-adenosine-receptors by adding adenosine receptors. Thus, when your not hopped up on caffeine, you have too many adenosine receptors (and therefore too much sleepy behavior), and even when you are on caffeine, the effects are muted.

Fortunately, it's pretty straightforward to reduce the number of adenosine receptors: you just stop ingesting caffeine, your body notices there's too many adenosine receptors, and removes them. This doesn't happen immediately, so you get withdrawal. Checking wikipedia, this should last 2–9 days at nuisance level. (Relative to the other drugs in my textbook, this is positively innocuous).

Also, it's worth mentioning caffeine's pharmacokinetics. The rate at which caffeine is metabolized is proportional to how much is in your system. Solving the differential equation gives you something like $A e^{-kt}$; the important thing to know is it has a half-life of about 6 hours.


Out of every course I took in college, psychopharmacology had by far the highest [actual IRL use] : [expected IRL use] ratio. Drugs are ubiquitous and having a solid understanding constantly pays small dividends.

Comment author: c_edwards 19 January 2015 04:29:45PM 0 points [-]

Fantastic explanation, and now I have another book to read eventually. Thanks!

Comment author: zedzed 19 January 2015 03:55:00AM *  3 points [-]

You might want to say something like "quick" instead of "fast" because homonyms (I first thought you were going to talk about intermittent fasting, which didn't make sense because of the hypoglycemia).

Why are you skeptical of whey protein? I've only ever heard good stuff, and I've spent enough time reading about nutrition to construct not-unreasonable arguments against almost every food. (Vegetables? Plants don't want to be eaten (except for fruit), so they contain bad-to-eat chemicals that humans almost certainly can't metabolize! Fruits? Have inferior nutrient density relative to vegetables!)

Thoughts on wheaty things: you can probably dismiss the paleosphere arguments against wheat. You're still dealing with a plant that doesn't want to be eaten and therefore contains toxic chemicals, but unlike other plants (e.g. broccolli), wheat doesn't come with killer micronutrient density. The naive approach would be to displace as many wheat-calories with vegetable/fruit/meat/nut/anything-else-with-higher-micronutrient-density calories. However, I also get the need for cheap calories, so if you're already eating all the micronutrients you need to, I can't really argue too hard against wheat.

Meat: near as I can tell, the important distinction is "processed/not processed" (see top comment thread in Lifestyle Interventions to Increase Longevity). There's also good reasons to prefer lean: better nutrient density, fewer toxins (which often are fat-soluble), although we again run into "more cost per calorie."

Caffeine: have you considered/tried not doing caffeine? I'm biased against it, since I don't really get the stimulant benefits but do suffer from withdrawal symptoms, but if you're a normal human, you're going to build tolerance, and suddenly your coffee-to-improve-performance-beyond-baseline has turned into coffee-to-keep-performance-at-baseline and it costs more than water. Also, chocolate contains caffeine and theobromine (another minor stimulant); consider restricting your chocolate consumption for days you need a performance boost and cut the coffee entirely.

I'll recommend Food and Western Disease as a book on nutrition that reads a bit like Gwern (1, 2) and lends itself to being updated upon (the book concludes with a recommendation for a version of paleo (which is almost closer to what you have here than what you'd find on, say, Mark's Daily Apple, but I used the same principles to arrive at eating soylent exclusively, and I'm confident that it could improve your nutrition plan significantly.)

Comment author: c_edwards 19 January 2015 02:12:05PM 0 points [-]

Swapped quick for fast. Thanks for pointing that out!

On whey protein - I was exposed to a lot of unverified health information by an ex. Much of that information came from a group of sources that take a conspiracy-theory approach to nutrition research (there's a big food industry that controls what gets published, and a lack of evidence for or any evidence against fact X is because of the food industry!). This is not to say that the facts I was exposed to were wrong, but rather that I need to verify them. So according to her, whey protein was bad. A quick google search for "whey protein health concerns" turns up quite a bit, although it's a mishmash of stuff. The mayo clinic has a list of side effects from using whey protein, and this article states that "increased whey protein added to the diet of rats increased tumors and cancers". On the other hand, wikipedia mentions the potential value of whey protein in reducing risk of cancer, heart disease, and diabetes. So the picture looks far from clear - I guess I have some more reading to do (unless someone else has already done the reading and can whey in?).

Thanks for the link on wheat stuff - because of the hypoglycemia, wheat has been a major building block of my meals. It's nice to know that I can continue that. Same goes for your suggestions on meat - most of my meat intake is chicken breasts, which fit in the non-processed lean meat category.

I really should try weaning myself off caffeine, and see how I feel. I was 20 before I started drinking it, and I was able to perform in school and work settings just fine without. That said, I'd like to do some more reading about how caffeine actually works - do you have another link to suggest? (if nothing comes to mind, I'll just spend some time with google).

Added Food and Western Disease to my reading list. Thanks!

Comment author: Manfred 19 January 2015 05:40:39AM 2 points [-]

A completely aesthetic recommendation: herbs and spices. For example, in your spinach salad, throw in some black pepper and aromatic herbs (e.g. buy a packet of mixed herbes de provence). And a little leftover bacon fat if you have any (Okay, that last one is not so healthy). Are you putting cumin in 70% of your stews yet? Consider it! :D

Comment author: c_edwards 19 January 2015 01:51:18PM 2 points [-]

Fantastic point. I'm blessed with fairly simple tastes when it comes to food, and I'm fine with some of my meals being fairly bland (pasta salad, for example, or spinach salads). But when it's easy and healthy, there's no reason not to make the food taste better.

Sidenote: the longevity article points out that garlic is linked to longer lifespans. So seasoning with garlic both increases flavor and health.

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