The problem with all processed oils is that all the fiber and the rest have been striped away, leaving only the extremely calorie dense oil. Processed oil like that takes up so little space in the stomach that's not filling, making it easy to eat too much food overall. At least in the US, this is compounded by so many processed foods having added oil as a primary ingredient or a cheap filler.

The healthiest way to ingest seed oils is undoubtedly to eat some seeds.