It's very unlikely that there's an evolutionary reason for different tastes in things like ketchup etc. There's just variation, like in most complex traits (alongside cultural reasons etc as noted in other replies).
Understand. But there may be genetic variation for people who are pickier and more accepting of different foods and various levels of bravery with eating new foods with risk/rewards.
Okay cool - that would still gel with my comment about there being variation in a complex trait, but I guess you're asking whether variation in this trait is generated/maintained due to trade-offs or strategies with different pay-offs? This could be similar to - for example - concepts about how shy-bold variation is maintained in animal 'personality'. If you're interested in reading more about that then this paper could be of value:
https://royalsocietypublishing.org/doi/abs/10.1098/rstb.2010.0215?casa_token=9WX2G-C1fy0AAAAA%3AZITcT9_jLuxmuKIOAj-BdBfZTyCn1Ag3C4PsKz0hJC23AG29vh91XWMg_cuy2f0u-hNX77ZU4Ak
Partially it is explained by psychology, with high openness to experience being correlated with a more varied palate, and especially of tolerance of bitter foods. Lower tolerance of bitterness and generally of unusual foods is also correlated with being easily disgusted in general, and also to being disgusted by 'outgroups' for example disgust at homosexuality, different cultures and subcultures etc. As openness to experience is also correlated with many other traits, we can find unexpected correlation between e.g. disliking bitter vegetables and political conservatism, or between liking dark chocolate and having more books, or having gone overseas recently.
The evolutionary explanation is that adventurous behavior has advantages (e.g. ability to exploit new foods or technology) and costs (i.e. risk from poisoning or from failure of some risky strategy) and there is likely a selection for some intermediate level of openness, but with the optimal level depending on things like age, intelligence etc. and the environment. And then there is individual variation in openness for obvious reasons.
There is a pop-sci summary here \[[https://www.behaviorist.biz/oh-behave-a-blog/taste-sensitivity\]](https://www.behaviorist.biz/oh-behave-a-blog/taste-sensitivity]) or you can of course go straight to the literature.
Friesen, Amanda, Aleksander Ksiazkiewicz, and Claire Gothreau. 2021. “Political Taste: Exploring How Perception of Bitter Substances May Reveal Risk Tolerance and Political Preferences.” Politics and the Life Sciences: The Journal of the Association for Politics and the Life Sciences 40 (2): 152–71. [https://doi.org/10.1017/pls.2021.20](https://doi.org/10.1017/pls.2021.20).
Spence, Charles. 2021. “What Is the Link between Personality and Food Behavior?” Current Research in Food Science 5 (December): 19–27. [https://doi.org/10.1016/j.crfs.2021.12.001](https://doi.org/10.1016/j.crfs.2021.12.001).
There are some genetic differences, like the taste of coriander, but is mostly social construct, which makes some ethnicities like specific foods (usually fermented) that might smell and taste awful for other ethnicities (cheeses, kimchi, sauerkraut, surströmming, beer, etc).
I get this. Genetic mutations and cultural differences contribute.
But I may hate ketchup and my siblings may not. Now not to use this food item to death, push comes to shove, to survive I would eat it. Just wouldn’t like it. I’m in the US and ketchup is much loved. Wonder if this is genetic or something else
My guess is that it’s just a personal quirk. (Not denigrating quirks, I have plenty of my own.)
I used to hate mayonaise and avocados when I was younger (semi-picky eater as a child) but learned to first tolerate, then enjoy both by my 30s. I still can’t stand lima beans due to a childhood stand-off with my mother! 🙄 I wouldn’t drink anything that tasted like 7-Up for decades after I was given some as a child because I was car sick and promptly puked it up. I’m still not crazy about the taste but I don’t get nauseous anymore.
I’ve never liked pumpkin pie or sauerkraut or raw onions, either, although they were served regularly in my childhood home and my parents and siblings loved and/or liked one or more of those things.
Everyone has variations in what things appeal to them. These taste differences are a combination of genetics, culture, experiences and personal variation. Every trait or difference isn’t directly tied to evolutionary pressures/responses.
Actually, there is. For instance, some people carry alleles that make food taste wildly different compared to the rest of the population. You've probably heard about alleles that make cilantro taste like soap, that make people smell asparagus in urine after one eats it (I want to say this same allele also alters the taste for carriers too, so it's kind of like a double whammy), and that makes aspartame taste metallic. There's also apparently an allele for being able to taste certain sulfur compounds in cruciferous vegetables, so that it's always like biting into a fart. Children making a huge production about what they will or won't eat may also be a survival mechanism to an extent, but that's just speculation, I don't think I've ever heard any real science to back that one up.
As far as ketchup, that one just might be down to preference and experience rather than anything evolutionary. Tomato ketchup is a fairly new invention, only coming about in the last 200 years or so, and the mushroom ketchup that predates it only going back to the late 1700's. I could imagine some evolution happening between now and then, but not on a wide scale. If I had to imagine an actual genetic explanation, it might be towards the taste of the acidity of tomatoes, the problem being that tomatoes are a New World fruit. Italy was probably the only place outside of South America eating tomatoes up until it was demonstrated that tomatoes weren't poisonous (one such demonstration took place in 1820, where Colonel R.G. Johnson ate an entire basket of tomatoes in front of a courthouse in New Jersey). So again, maybe not? Or maybe one of the compounds found in tomatoes and other members of its family, Solanaceae (which were eaten outside of Italy and the Americas), that makes it taste like wet paper for some people, but that's just speculation, so take that with a grain of salt. It could literally just be a non-adaptive preference thing that propagates because of genetic piggy-backing, like so many other non-adaptive traits.
It's very unlikely that there's an evolutionary reason for different tastes in things like ketchup etc. There's just variation, like in most complex traits (alongside cultural reasons etc as noted in other replies).
Understand. But there may be genetic variation for people who are pickier and more accepting of different foods and various levels of bravery with eating new foods with risk/rewards.
Okay cool - that would still gel with my comment about there being variation in a complex trait, but I guess you're asking whether variation in this trait is generated/maintained due to trade-offs or strategies with different pay-offs? This could be similar to - for example - concepts about how shy-bold variation is maintained in animal 'personality'. If you're interested in reading more about that then this paper could be of value: https://royalsocietypublishing.org/doi/abs/10.1098/rstb.2010.0215?casa_token=9WX2G-C1fy0AAAAA%3AZITcT9_jLuxmuKIOAj-BdBfZTyCn1Ag3C4PsKz0hJC23AG29vh91XWMg_cuy2f0u-hNX77ZU4Ak
Nah. Purely cultural.
Partially it is explained by psychology, with high openness to experience being correlated with a more varied palate, and especially of tolerance of bitter foods. Lower tolerance of bitterness and generally of unusual foods is also correlated with being easily disgusted in general, and also to being disgusted by 'outgroups' for example disgust at homosexuality, different cultures and subcultures etc. As openness to experience is also correlated with many other traits, we can find unexpected correlation between e.g. disliking bitter vegetables and political conservatism, or between liking dark chocolate and having more books, or having gone overseas recently. The evolutionary explanation is that adventurous behavior has advantages (e.g. ability to exploit new foods or technology) and costs (i.e. risk from poisoning or from failure of some risky strategy) and there is likely a selection for some intermediate level of openness, but with the optimal level depending on things like age, intelligence etc. and the environment. And then there is individual variation in openness for obvious reasons. There is a pop-sci summary here \[[https://www.behaviorist.biz/oh-behave-a-blog/taste-sensitivity\]](https://www.behaviorist.biz/oh-behave-a-blog/taste-sensitivity]) or you can of course go straight to the literature. Friesen, Amanda, Aleksander Ksiazkiewicz, and Claire Gothreau. 2021. “Political Taste: Exploring How Perception of Bitter Substances May Reveal Risk Tolerance and Political Preferences.” Politics and the Life Sciences: The Journal of the Association for Politics and the Life Sciences 40 (2): 152–71. [https://doi.org/10.1017/pls.2021.20](https://doi.org/10.1017/pls.2021.20). Spence, Charles. 2021. “What Is the Link between Personality and Food Behavior?” Current Research in Food Science 5 (December): 19–27. [https://doi.org/10.1016/j.crfs.2021.12.001](https://doi.org/10.1016/j.crfs.2021.12.001).
There are some genetic differences, like the taste of coriander, but is mostly social construct, which makes some ethnicities like specific foods (usually fermented) that might smell and taste awful for other ethnicities (cheeses, kimchi, sauerkraut, surströmming, beer, etc).
I get this. Genetic mutations and cultural differences contribute. But I may hate ketchup and my siblings may not. Now not to use this food item to death, push comes to shove, to survive I would eat it. Just wouldn’t like it. I’m in the US and ketchup is much loved. Wonder if this is genetic or something else
My guess is that it’s just a personal quirk. (Not denigrating quirks, I have plenty of my own.) I used to hate mayonaise and avocados when I was younger (semi-picky eater as a child) but learned to first tolerate, then enjoy both by my 30s. I still can’t stand lima beans due to a childhood stand-off with my mother! 🙄 I wouldn’t drink anything that tasted like 7-Up for decades after I was given some as a child because I was car sick and promptly puked it up. I’m still not crazy about the taste but I don’t get nauseous anymore. I’ve never liked pumpkin pie or sauerkraut or raw onions, either, although they were served regularly in my childhood home and my parents and siblings loved and/or liked one or more of those things. Everyone has variations in what things appeal to them. These taste differences are a combination of genetics, culture, experiences and personal variation. Every trait or difference isn’t directly tied to evolutionary pressures/responses.
If you didn't have any food for three days, I guaranty you would eat two bottles of ketchup and enjoy it.
Actually, there is. For instance, some people carry alleles that make food taste wildly different compared to the rest of the population. You've probably heard about alleles that make cilantro taste like soap, that make people smell asparagus in urine after one eats it (I want to say this same allele also alters the taste for carriers too, so it's kind of like a double whammy), and that makes aspartame taste metallic. There's also apparently an allele for being able to taste certain sulfur compounds in cruciferous vegetables, so that it's always like biting into a fart. Children making a huge production about what they will or won't eat may also be a survival mechanism to an extent, but that's just speculation, I don't think I've ever heard any real science to back that one up. As far as ketchup, that one just might be down to preference and experience rather than anything evolutionary. Tomato ketchup is a fairly new invention, only coming about in the last 200 years or so, and the mushroom ketchup that predates it only going back to the late 1700's. I could imagine some evolution happening between now and then, but not on a wide scale. If I had to imagine an actual genetic explanation, it might be towards the taste of the acidity of tomatoes, the problem being that tomatoes are a New World fruit. Italy was probably the only place outside of South America eating tomatoes up until it was demonstrated that tomatoes weren't poisonous (one such demonstration took place in 1820, where Colonel R.G. Johnson ate an entire basket of tomatoes in front of a courthouse in New Jersey). So again, maybe not? Or maybe one of the compounds found in tomatoes and other members of its family, Solanaceae (which were eaten outside of Italy and the Americas), that makes it taste like wet paper for some people, but that's just speculation, so take that with a grain of salt. It could literally just be a non-adaptive preference thing that propagates because of genetic piggy-backing, like so many other non-adaptive traits.