There was an idea in 'Fat Head' where the narrator pokes fun at the idea that we are a species who's evolution has made us so that we crave foods that are actually killing us. It's not proof that we can't crave foods like sugar, fats and salt that might be harmful to us, but I think it sets up a health amount of skepticism towards the idea that our innate cravings are in fact harmful.
"...we are a species who's evolution has made us so that we crave foods that are actually killing us."
"...it sets up a health amount of skepticism towards the idea that our innate cravings are in fact harmful."
It's modern processed food that's harmful.
We evolved to cope with the amount of salt, sugar, carbohydrates etc. that was readily available to our ancestors on a hunter-gatherer diet (we would've reached an evolutionary dead end otherwise if our "innate cravings" were not useful to us in a survival sense) - you would have to do a lot of hunting and gathering to get the amount of salt, sugar, saturated fat etc that a single fast food meal provides - it was relatively rarer so we have cravings to ensure we got enough of them back when they were scarce.
Evolution is a very slow process. Adding syrup to carbonated water, advertising the crap out of it and selling it at huge markup (coca-cola) can happen over the course of a single human's lifespan.
Salt is a very important part of a human's diet and was a major trade item for all of recorded history. Salt has been used as a preservative for meat for as long as I'm aware of. Animals often sit and lick natural salt deposits.
There is a common belief that meat and especially fat are bad for you and cause heart disease, which is the particular idea that Fat Head makes fun of. He reduces his carb and sugar intake and lowers his cholesterol and loses weight.
I quit drinking soda and reduced my sugar intake because it made me feel bad. I sometimes crave sugar after running a lot or when I'm tired and I will occasionally drink a soda, but I usually regret it. Same with candy etc.
I can only speak for myself, but the idea that my natural cravings and the reaction of my body are good indicators of what is healthy has been very successful for me. I currently believe that fat and meat, plus vegetables are very health and I crave all these things. My body is very sugar sensitive and so I avoid it because of how I feel. The guide that my evolutionary tastes are not trying to kill me seems to be a pretty good guide towards finding a healthy diet, and I believe it will serve me better than the National Health Services recommendations have. If you believe that there is good reason that evolution may be guiding you towards something unhealthy, you may be right, but my default answer is the it is correct unless there is a better explanation.
"If you believe that there is good reason that evolution may be guiding you towards something unhealthy..."
I don't think there's any doubt about this. Compared to evolutionary rates, the typical diet in the west has changed at lightning pace from just a few decades ago, meaning our bodies and taste buds are behind the curve. We need willpower and common sense to have a healthy diet, rather than raw survival instincts.
Unfortunately what's driving change in our diet is the demand for companies to serve food with high profit margins and low cost raw materials (e.g. high-fructose corn syrup). Capitalism is great for providing us with cheaper clothes and ever-cheaper computing power, but providing cheaper food means providing crappier food. There's no Moore's Law for food.
I think it was here on HN I read about studies done in remote communities (possibly some remote whaling community) that had recently become westerised, and the diet quickly shifted to one more similar to a typical American diet. Within 5-10 years (or a relatively short time frame, can't remember exactly) obesity and type-II diabetes rates exploded.
Another interesting story was reports from surgeons who operated on injured Afghan fighters from the current conflict. Normally when operating on westerners, you expect a certain amount of yellowish fatty tissue surrounding the major internal organs. This wasn't present on Afghan locals, which surprised the surgeons who were so used to seeing it on western patients and pretty much assumed it was normal up till that point. The difference was down to diet.
I like your comment but you are confusing the issue. Your argument is that processed food is bad for you and cheaper because of production scale and I completely agree. My point is that if I take two meals and put them in front of someone, one with a red steak wrapped in bacon and vegetables and one is a hamburger and fries, I suspect most people will chose the high fat meat and veggies. However, the government has been pushing the food pyramid http://www.nal.usda.gov/fnic/Fpyr/pmap.htm as a school indoctrination program for as long as I can remember. As far as I can tell that hamburger fits right in with your six to 10 servings of bread a day, and they would tell you it's the bacon that is making you fat and giving you heart disease. So yes, cheaper food is worse for you generally speaking but that is about economics, not evolutionary tastes.
Cravings can be trained and influenced by person's knowledge, I think. Example: When I was young (and stupid :) I drunk a lot of cola. I literally craved it, I chain-drunk it whole day. Then I learned what that thing actually is, and then my doctor told me my blood sugar is entering regions where it shouldn't be. I didn't touch the stuff since, and now the mere sight of it disgusts me. I tried to drink it, and I realize I actually hate the taste now. I have no idea how I could enjoy it years ago. Maybe I'm just impressionable, but here it goes.
I still like the sweets, however, even though with my complexion it is best not to overdo them. I guess it has its limits. But if I gave in fully to my cravings in this area, I'd probably have a very serious health problem by now. So trusting "evolutionary tastes" is a dangerous path - unless you put it under strict control of the higher brain, I believe it can seriously harm you.
Indeed. Some processing is good, but a lot of it just makes the food too easy to eat. I would argue that even processing food at home, such as mashing potatoes can be a problem unless you are careful about the portion size - i.e. remember how many potatoes were used to make it.
Our bodies are full of feedback systems that only work in our natural (i.e. pre-civilization, pre-agriculture, hunter-gatherer, nasty, brutish, short) environment. It should be no surprise that our food cravings are among them.
There are other fun examples. One is that our breathing reflex is based on CO2 concentration being too high rather than O2 concentration being too low, even though O2 concentration is more important! Breathe into a closed system with a CO2 scrubber in it and you'll quickly get loopy and then pass out from lack of oxygen (and then die, if nobody disconnects you) all the while feeling fine. Another is that the iris of the eye responds to visible light but protects against more. Looking at the Sun is normally OK (uncomfortable, but tolerable) because the feedback is set up properly, but during the totality of a solar eclipse (which of course occurred back then, but not often enough to matter, apparently) your iris will crank open and let in tons of UV from the Sun's still-visible corona, frying your retina if you look at it.
It makes a great deal of sense that we'd evolve strong cravings for things which are good for us in small quantities but bad for us in large quantities when those things were scarce in the distant past, and death came early by other means for other people, well before a bad long-term diet could kill. That doesn't mean this must be what happened, but given how much humans love sugar, and how rare concentrated sugar would have been for our ancestors, it's no surprise if sugar turns out to be bad for us when consumed in the quantities we really want.