Initially, there's a bit of self-suggestion involved, but after consistently eating a bland diet, the body adapts and begins to appreciate the unique flavors of the blandness.
If we rate taste and oiliness on a scale of 0-100, each point has its unique flavor. Those who prefer strong flavors would be in the 80-100 range. Suddenly eating something in the 20-40 range would feel very uncomfortable, creating pressure or even a sense of threat, leading to resistance.
However, by gradually lowering the level, or forcing yourself to eat 20-40 for three consecutive weeks, the body slowly gets used to 20-40. After a longer period, more than seven weeks, returning to 80-100 becomes just as unpalatable as before.