They once did a study. They blindfolded people and had them eat steak. They said the steak was delicious.
Then they took away that plate, and brought out another plate of a steak. They told them to take their blindfolds off, and eat this new steak. The steak had blue spots. They told them they MUST eat 3 bites.
They reported that they felt disgusted by the blue steak. It tasted disgusting. And they felt insulted to have to eat that. They raised concerns throughout the whole thing about food safety.
Then after they documented the results, it was the same steak in both trials. The blue spots were just liquid food coloring dribbled on. Totally harmless. The steak was always safe to eat. The food dye was flavorless.
So when people couldn’t see the food, it was delicious. When they did see it, they had to hold back throwing up as they ate it.