yet another example of the "just force yourself to endure discomfort" philosophy of life that is relentlessly popular
"you have to stop being a picky eater and learn to tolerate new foods..."
gagging is extremely stressful. it is such an intensely, sharply unpleasant experience with the added stress of trying not to spit your mouthful of food all over yourself/the table. The sweating and heart palpitations of trying to force down a swallow of something that is viscerally repulsing you is an exquisitely negative feeling. My palms are sweating just thinking about it.
This experience can cause novelty itself to cause fear and apprehension. Just the prospect of eating something unfamiliar can cause fear and nausea, because past experiences were so incredibly negative
now, the physiological effect of fear is that it suppresses the activity of the digestive system. this deadens your appetite and makes it more likely that eating will make you feel sick. So the negative experience is compounded
but on a milder level, the depression of simply not enjoying food is very negative for your life. I can say confidently that the low quality of cafeteria food at my college increased my day to day depression. eating is one of life's pleasures and when it becomes a repulsive chore, that builds a slow resentment of being alive
therefore, it is not good to force yourself to eat things you do not like, instead it is better to cultivate greater curiosity and adventurousness regarding foods you may have never been exposed to before. importantly, you must do it in a safe enviroment because before you can enjoy food you have to undo all the negative experiences of being forced to eat food you hate
cooking recipes for yourself can be a good way to do that because it is creative and active which gives a sense of playfulness which leads to power and agency
do not try new things in social gathering where there is pressure from other people
foraging and gardening is incredibly helpful because the food is fresh and there is a great sense of security and connectedness in it. you know where the food comes from you know that it is good you know it came from the earth beneath your feet. eating something right off the plant is an experience that unlocks your inquisitive and animalistic side instead of making you feel pressures and stresses from social expectation.
You feel like an animal trying to bite something investigating whether it is food. Does a wild animal get yelled at when it bites something that is not edible and spits it out? of course not.
Also once you have had positive experiences eating things from outside your instincts tend to be more accessible to you. humans in the modern world are taught that outside things are not for eating, generally, so they silence the instinct that urges them to eat plants.
Personally i think this is a big part of many aversions to vegetables, if you are told that leaves outside are all poison and bad, it is hard to turn off that apprehension with a leaf on your plate. but if you experience eating plants that grow out of the ground in the world around you, that can awaken that instinct toward plants as food again
i also have been known to buy a new fruit I've never experienced before and sit on the floor on a towel and puzzle through how to eat it, intentionally tuning in to all the sensory aspects of that experience