system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do our bodies have the ability to dislike food when we need it to live?
gpt
In nature, bitter or sour flavours can indicate poisonous, inedible, burnt or rotten food. Notice how lot of people don't like bitter foods - such beer or unsweetened coffee - the first time they try them, but they gradually start to appreciate them because their brain gets to know they aren't harmful. The same goes for cheese,  some people just can't stand the smell and taste cause their brain thinks it's rotten milk. Stuff like blue cheese is liked by even less people cause it has mold, another thing your brain wants to avoid.

For the rest of flavours, it's mainly because the abudance of food we have made us picky. If we can choose between different foods, we are wired to go for the ones that have the highest nutritional value, so food with lot of sweet taste or umami taste (which generally indicates high fats and proteins).

Hunger is the best spice in the world and lot of people never experience true hunger, which only kicks in after like one day of fasting.