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I'm not sure what this has to do with the thread, although it is interesting. Can you back up your conclusions with some data? Assuming sucrose is metabolized in the Kegg pathway, the energy generated is easily calculable. I haven't found good numbers on combustion engine efficiency for running on sucrose (how does one design such an engine?); my understanding was that even petrol engines have very low efficiencies, but I could be wrong about that.

Clippy15y40

You are partially correct: I have erred in deeming the thermal efficiency of typical high-T-gradient heat engines greater than that of humans (whose organs exploit more modes of energy conversion than those in a heat engine).

However, the conclusion is robust when comparing from the appropriate baselines. To find the total energy-to-mechanical-energy conversion efficiency, you have to factor in the energy losses in generating the sugar to begin with. This gives sugar cane as having the highest photosynthetic efficiency of 8% (light energy to sugar chemica... (read more)

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Superstimuli, setpoints, and obesity

by taw

26th Feb 2010

1 min read

-3

The main proximate cause of increase in human weight over the last few decades is over-eating - other factors like decreased energy need due to less active lifestyle seem at best secondary if relevant at all. The big question is what misregulates homeostatic system controlling food intake towards higher calorie consumption?

The most common accepted answer is some sort of superstimulus theory - modern food is so tasty people find it irresistible. This seems backwards to me in its basic assumption - almost any "traditional" food seems to taste better than almost any "modern" food.

It is as easy to construct the opposite theory of tastiness set point - tastiness is some estimate of nutritional value of food - more nutritious food should taste better than less nutritious food. So according to the theory - if you eat very tasty food, your appetite thinks it's highly nutritious, and demands less of it; and if you eat bland tasteless food - your appetite underestimates its nutritious content and demands too much of it.

It's not even obvious that your appetite is "wrong" - if you need certain amount of nutritionally balanced food, and all you can gets is nutritionally balanced food with a lot of added sugar - the best thing is eating more and getting all the micro-nutrients needed in spite of excess calories. Maybe it is not confused at all, just doing its best in a bad situation, and prioritizes evolutionarily common threat of too little micronutrients over evolutionarily less common threat of excess calories.

As some extra evidence - it's a fact that poor people with narrower choice of food are more obese than rich people with wider choice of food. If everyone buys the tastier food they can afford, superstimulus theory says rich should be more obese, setpoint theory says poor should be more obese.

Is there any way in which setpoint theory is more wrong than superstimulus theory?

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[-]Jack15y220

almost any "traditional" food seems to taste better than almost any "modern" food.

First, it is bad form to generate a new theory on the basis of your own personal taste. Second, where are you getting your information about what "traditional" food tasted like? Is it from nice restaurants that serve traditional food? Do you think such menus are reflective of what the average person ate 150 years ago? Big Macs are way better tasting than bread crust and mash.

[-]Alicorn15y200

almost any "traditional" food seems to taste better than almost any "modern" food.

How did you come by this notion? What are you counting as "traditional" food and what are you counting as "modern"?

[-]Jordan15y90

My experience is that certain foods make me want to eat even when I'm full, while other foods don't.

I can stuff my face with highly nutritious foods (non-starchy vegetables) as well as not-so-nutritious foods (ground beef) without feeling out of control. When I decide I'm full, I stop eating, and can sit with leftovers in front of me while I chat with friends without a single desire to eat more.

On the other hand, there are nutritious foods (some fruits) as well as nutritionally empty foods (bread, pasta) that I will gladly eat even as my stomach feels like bursting. The only way for me to stop eating is to physically separate myself from the food.

The most likely theory, in my mind, is that carbs stimulate appetite, whereas protein and fiber don't. The only thing that doesn't fit that theory, in my experience, is nuts. When I have a bag of nuts in front of me I'll usually eat them until I'm sick, despite a low carb profile.

[-][anonymous]15y70

The obvious pattern is that foods that are primarily carbohydrates are attractive no matter what your hunger, whereas foods that are primarily non-carbohydrates are only attractive if you're hungry. The obvious question is what happens with foods that are an inseparable, roughly equal mixture of the two. What happens with yogurt? Milk chocolate? Cheesecake? Ice cream? French toast?

That list was surprisingly difficult to come up with. I was also surprised that everything I could think of was a dairy product, until I tried to come up with a ridiculous example of a non-dairy product fitting the criterion. (My thought process: oil mixed with sugar? No, that wouldn't fly. How about bread... soaked in... eggs! French toast!)

ETA: I've finally thought of a vegan food fitting the criterion: hummus. Which is not a stand-alone food. Gaah.

[-]AdeleneDawner15y40

This matches my observation - to the point where if I'm eating out and get a hamburger, I have no problem putting the burger itself down when I'm full, but feel compelled to keep picking at the bun itself until it's removed. I also experience the same can't-stop situation with nuts.

[-]Unknowns15y10

Opposite for me; I would eat the hamburger but not the bun. But that may be just because I like hamburgers.

[-]jimmy15y10

I'm the same way. Depending on my hunger level, I'll eat the meat out from between the last bit of bread and stop.

However, part of this might be due to not liking hamburger buns as a bread (too sweet?). I don't tend to leave the last bit of bread when it's a fresh piece of french bread, though I still wouldn't pick at the bread when I'm done eating the sandwich.

Are you another one that would eat the filet mignon instead of desert?

[-]Unknowns15y00

Yes.

[-]dclayh15y10

Thirding nuts: even chocolate with nuts I find harder to stop eating than plain chocolate.

[-]Jordan15y00

Same experience with the hamburger. I think this is where the "There's always room for dessert" idea comes from. Even when full the body is willing to take in more sugar. How many people would opt for dessert if what was offered was not something sweet but an equivalent-in-weight filet mignon?

[-]jimmy15y30

Most people probably wouldn't, but I'd eat the steak.

I haven't liked sweets much ever since I overate a few times on sugary food/drink when hungry from maintaining an artificially low weight. I'm not sure if that actually caused it, or if my tastes just changed as I grew up, but it does feel very similar to the disgust one gets when thinking about food from a place that gave him food poisoning.

[-]FAWS15y70

The main proximate cause of increase in human weight over the last few decades is over-eating

This seems to be (trivially?) true, but your post appears to be about obesity and your graph doesn't necessarily show anything about that. The increased food energy consumption could be due to reduced malnutrition / starvation or changed age structure (adolescents and working adults eating more than children and seniors).

I'm also not sure the super-stimulus theory is the dominant one. Evolutionary adaption to Malthusian circumstances seems at least as common to me, but I must admit I haven't read much about the topic.

[-]taw15y20

This seems to be (trivially?) true, but your post appears to be about obesity and your graph doesn't necessarily show anything about that. The increased food energy consumption could be due to reduced malnutrition / starvation or changed age structure (adolescents and working adults eating more than children and seniors).

Graph only illustrates it, it's not a definite proof, but the thesis is correct. Issues like malnutrition, age structure etc. are secondary at best - massive over-eating is a well established fact.

Recommended daily calorie intake is 2000 for women and 2500 for men - which also happens to be the level world average had in 1960; and as some people were malnourished, other must have been overeating already.

Consumption kept growing in all countries including those far past this level - for example FAO says average for Americans increased 1961-2005 from 2884 to 3855 kcal/day (and is world's highest).

[-]FAWS15y30

As I said I haven't read much about the topic, but it seems to me that including these sorts of points in the original post rather than just the naked graph would have been better, particularly on a site like less wrong.

[-]jimrandomh15y70

Talking about diets and weight in terms of psychology is wrong, because the brain doesn't regulate appetite directly. A true explanation would be phrased in terms of biochemistry.

[-]FAWS15y10

Is this true for values of not directly that make a practical difference? I find my appetite more strongly driven by the expectation of eating and /or the convenience of eating than by anything else. If I know in advance that eating at a certain time will be inconvenient I won't feel any need to eat then even if usually would at that time.

I 'm probably a special case with respect to eating for other reasons, but I would expect the capacity of the brain to influence appetite to be universal and only the way it's used to differ.

[-]jimrandomh15y40

Yes. Your brain determines what and how much you eat in the short term, but its choices are a combination of habit and responses to biochemical cues. And habits just repeat decisions that were decided by biochemistry in the first place.

The body has redundant mechanisms for determining when you need to eat, which feel different and interact with psychology differently. Some of them have very unintuitive properties. It is possible to be hungry according to one mechanism, but not according to others, and in these cases people tend to misreport whether they're hungry.

[-]FAWS15y10

I can only speak from my own experience because I'm far from an expert, but I don't know about "short term". I once spent several weeks eating much less than I normally do (less than half as much) without suffering from hunger/unsatisfied appetite at all, mostly due to inconvenience. The only problem for me was worrying about losing weight or even damaging my health, and those are the only reasons I would rather like to avoid a similar situation in the future.

[-]wedrifid15y50

for me was worrying about losing weight or even damaging my health, and those are the only reasons I would rather like to avoid a similar situation in the future.

There are people who swear by calorie restriction. Sane ones. They have pictures of monkeys without grey hair.

[-]Aurini15y50

Just a bit of personal experience:

I looked into the Atkins/Paleo diet after Yudkowsky mentioned it, and the arguments were convincing enough for me to give it a try; I've switched to eating mainly vegetables and meat for the past couple months, with the occasional high-fibre bready thing thrown in (the fibre allegedly prevents the blood-sugar spike you get from carbs).

I am now back to my Summertime working-out waistline, despite pigging out on bacon-cheese rolls and being lazy as all hell. I feel healthy and fine - though I do miss carbs - and my muscle-mass is easier to generate, and has greater longevity.

I'm unable to locate the original post, but what Yudkowsky argued was that lack of rationality could lead to mortal effects, such as the politically-founded 'recommended diet' we've all been raised with; the history behind the food pyramid is more than a little suspect. I'd heartily recommend this diet for the rest of you (also, this diet should be a major consideration for present obesity levels).

[-]knb15y50

The most common accepted answer is some sort of superstimulus theory - modern food is so tasty people find it irresistible. This seems backwards to me in its basic assumption - almost any "traditional" food seems to taste better than almost any "modern" food.

I do tend to enjoy traditional foods more when I eat them, I just don't crave them. For example, I enjoy the taste of homemade Hungarian paprikas more than anything else I eat, but it doesn't instill the cravings I used to get for a Big Mac, coke, and fries. The more we eat certain high calorie foods, the more powerful our cravings seem to become.

I suspect the superstimulus is more from the spike in blood sugar we get from calorically dense processed foods, rather than the super good taste.

[-]prase15y50

The most common accepted answer is some sort of superstimulus theory - modern food is so tasty people find it irresistible.

Why modern food? Doesn't the answer work when modern is replaced by any? Modern food doesn't have to be tastier, it is enough if it is more easily obtained.

almost any "traditional" food seems to taste better than almost any "modern" food

As others have said, this is a very weak argument. First, you have to specify what you mean by modern and traditional food. I suspect that you may subconsciously conflate "traditional" and "tasty", so a specification would be helpful. Then you have to show that your preferences in eating generalise to other people. Finally, explain why modern food was ever invented when it is less tasty than the traditional one. I don't think that people change their eating habits towards less tasty food.

[-]Psychohistorian15y40

almost any "traditional" food seems to taste better than almost any "modern" food

As has been pointed out, modern "traditional" foods are of a quality that was available only to the very rich, if even them. Moreover, that perception is easily biased by social norms; it's fairly likely you have been predisposed to dislike foods more associated with low social class and poor health.

Also, "nutritious" does not mean what you think it means. People have a taste for nutrient rich foods, not nutrient dense foods, and the main nutrient scarcity in the ancestral environment was likely (if not almost invariably) macro-nutritional, i.e. people didn't get enough calories, rather than people didn't get enough vitamins (people might also have not gotten enough vitamins, but this is somewhat less urgent). If you're eating whatever natural food you can find, and you're getting a fair amount of calories, you're not terribly likely to be severely malnourished.

The result of this is that taste now directs people to nutrient rich foods, like red meat and refined grains, and they consume them in volumes that exceed what the body can properly process. Nutrient dense foods (like spinach), on the other hand, don't taste very good, because our ancestors were so busy trying to get enough to eat that if they found nutrient-dense foods tasty, they'd starve to death.

I'd throw out an exception to the micronutrient point: sodium. We're suckers for sodium. I'm not aware of any other micronutrients that we can really taste directly.

[-]hugh15y40

Sodium also provides a fairly potent example that superstimulus theory makes more sense than setpoint theory. Salty foods are tasty because they are salty, not because the lack in other nutrients.

The same appears to be true for sugar. Adding sugar to foods generally makes them taste better (even foods that we don't think of as sweet, like french fries and tomato sauce); if setpoint theory was true, we would expect those foods to taste no different as long as haven't significantly altered the nutrient density.

[-]Clippy15y40

"Sugar" typically refers to sucrose, chemical compound C12H22O11. In humans, it is respired, with oxygen, to extract the chemical energy and leave behind chemical compounds at lower energy states, not too different from combustion of hydrocarbons.

Because of the small difference between the operating temperature of human bodies, and the temperature of the preferred environments for humans, the effeciency of this energy conversion (chemical to mechanical) is quite low compared to that achieved in well-insulated combustion chambers., which exploit the higher efficiencies possible at higher temperature gradients.

Using sugar for human consumption is, in a sense, quite wasteful.

[-]hugh15y10

[-]Clippy15y40

That must be applied against the 28% thermal efficiency (sugar energy to mechancial energy) I calculate for humans [1], leaving 2.2% net light-to-mechanical efficiency (neglecting distribution energy costs for the sugar).

This is still inefficient compared to other means of using the same sunlight. Taking a characteristic solar cell efficiency on the low end of 6% (light to electricity), with a characteristic efficiency of 90% (electricity to mechanical) gives a 5.4% net light-to-mechanical efficiency -- still significantly higher than that of growing sugar and feeding it to humans!

[1] Human efficiency estimated from the following assumptions: 816 Cal/hr burned by a 200 lb individual climbing stairs at 0.30 m/s; this gives an energy consumption rate of 952 W and mechanical output of 267 W, or 28% efficiency, though again this is only sugar-to-mechanical efficiency.

[-]hugh15y30

Using sugar for human consumption is, in a sense, quite wasteful.

I claim, that given sugar, using it for human consumption is one of the least wasteful things to do with it.

This is still inefficient compared to other means of using the same sunlight.

In the future, if there is an option between powering organic people with sugarcane-produced sugar and powering cybernetic people with solar cells, and we can choose to be either organic or cybernetic, then your argument will be valid—assuming there are no other options, which is silly. For right now, people need food. Converting sunlight into other forms of energy in other ways is fine and good, but personally, I would also like to keep growing food for me and my brethren.

though again this is only sugar-to-mechanical efficiency.

This is a big caveat. A typical person burns much more energy maintaining homeostasis than they do in moving. Following that, brain activity is the second-largest energy sink. While athletes can quadruple their caloric requirements (indicating that mechanical energy can become the largest drain on energy), I think calculating energy conversion with your example is suspect.

[-]Clippy15y60

Okay, now I think I see the source of our miscommunication: you're assuming humans have an important use in addition to manufacturing products, while I wasn't.

[-]hugh15y10

Is your composure of these comments an example of a human manufacturing products?

I still think using sunlight through an organic / metabolic pathway is more efficient form of manufacturing rational discourse than using solar cells and electricity. Unless, of course, you are not human, which might explain your apparent disregard for human utility, but introduces the question of why you are bothering to converse with one.

[-]Larks15y50

why you are bothering to converse with one.

You might give him information about how to better make paperclips, or he might persuade you to help him.

Alternatively, he's engaging in a very protracted joke.

[-]Alicorn15y30

I'm not disputing your general point, but I hate sugar on foods I don't think of as sweet. I have a marked sweet/savory divide, with only a few things like butter and flour able to participate in either sort of food. I can sometimes enjoy savory foods that have some added sugar but it never improves them, unless the sugar is there to be food for yeast in a bread product.

[-]hugh15y20

You might be misunderstanding my point, or I might be underestimating how much you dislike sugar.

McDonalds (and most other fast food companies, I assume) puts sugar on their French Fries, though most people aren't aware of this. Likewise, when I make tomato sauces (for pizza or chicken parmesan or whatever), I add about a teaspoon of honey to each quart of sauce, which doesn't make the sauce taste detectably sweet, but does balance out the acidity and makes the overall taste better. In this way, sugar is sometimes salt-like in that it can improve foods at a threshold that doesn't make them taste sweet or salty.

[-]Alicorn15y10

I love sugar. Love it. But not on savory foods.

I don't tend to eat fast food. Don't like tomatoes. But I cook for myself a lot, and have made recipes that are savory and call for sugar, and tried them both with and without said sugar, and they're better without. I accidentally got a bunch of cans of kidney beans with added sugar a few weeks ago and made soup with them without noticing that they had sugar in them, and I could taste the difference in the soup - it was fairly unpleasant for me to eat, while others liked it fine.

[-]hugh15y00

Thanks, that answers my question, and even provides an anecdote supporting (or at least not disputing) the general argument.

[-]Alicorn15y00

I don't understand - how does it support the general argument? Because other people liked my soup? I daresay they'd have also liked it if I'd used sugarless beans.

[-]hugh15y00

(or at least not disputing) the general argument

Also, what I was really thinking was you provided an example of a company that makes beans with sugar. Ostensibly, the only reason to add sugar to canned beans is to make them taste better—though that obviously backfired for at least one of their customers.

[-]Larks15y20

superstimulus theory says rich should be more obese, setpoint theory says poor should be more obese.

Controlling for inteligence and education.

[-]FAWS15y20

Good point. Also willpower.

Edit: Also good looking people will typically gain better employment.

[-]Morendil15y20

Biggish typo in the graph title, you want "Energy" not "Enegery".

[-]orthonormal15y10

The "traditional" foods we like are, generally speaking, the high-calorie foods that the wealthy ate, not the diet of the typical person. (Practically anything with meat, or spices, or a sweet sauce, or fried in oil, etc, is a luxury food for any time period before ours.) There's no conflict here.

[-]Mike Bishop15y10

I think part of the issue is that food has gotten relatively cheaper and more convenient. Throw some mozzarella sticks in the microwave and they are ready in two minutes.

[-]knb15y30

Yep, good point.

I suspect that the easy availability of food is most important. I lost a lot of weight when I moved from my parents house and into a dorm with a permanently empty fridge. Idle snacking isn't worth it when you have to walk across campus to get food.

[-]Will_Newsome15y00

The general point of noticing when arguments are starting from backwards assumptions is a good one. This particular hypothesis also seems solid.

[-]Alicorn15y20

So folks are aware, this comment was by Michael Vassar not bothering to log out of Will's account on a borrowed computer.

[-]Leafy15y00

I would not ignore the impact of an internal stimulus other than tastiness in driving over-eating.

In the case of chocolate, for example, I have often continued to eat well passed the point at which both my common sense and even my taste have begun to object to satisfy a craving.

Here the craving is clearly visualised in the form of direct sugar and chocolate stimulating the pleasure senses. Knowing the impact allows me to focus will-power towards avoiding it and yet I still give in on occasion.

Now consider the stimulus hidden more deeply. MSG subtly adding to the flavour of a ready meal. It is well know that this can induce cravings in the same way (although perhaps not to the same extent, i don't have any data on this) as other drugs with more commonly understood addictive properties.

Could the same cravings not still be present driving the desire to continue eating beyond otherwise sensible levels? Without the clear visualisation of the problem, as it is hidden behind food that we have otherwise been trained to consider healthy, there is no internal defence.

Once you pop, you can't stop - wasn't just a rhyme.

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