It's not that complicated. Eating more leads to greater body mass, which requires higher caloric intake to sustain. Eating less leads to the opposite.
If you gain 20 pounds, then you need to eat more relative to your previous weight in order to maintain your current weight (including that extra 20 pounds). If you lose 20 pounds, you have to eat less to maintain that new weight.
If you gain 20 pounds, then you need to eat more relative to your previous weight in order to maintain your current weight (including that extra 20 pounds). If you lose 20 pounds, you have to eat less to maintain that new weight.