Fat actually satiates you more than almost anything else, so I suspect your culprit is sugar, not fat. If you cooked those veggies in some butter or olive oil, I would bet you’d get full faster.
Possibly, I think I recall reading about the fat+sugar being ultra nasty because your brain never wants to stop this mouth sensation. That said, I don't feel the same when eating fatty stuff, it's more nausea than what I feel with veggies.
My diet habit shifted 180deg in 48h, it's a weird realization:
1) eating raw vegetables tickles your brain differently (raw veggies make you feel full faster)
2) most probably because there's no fat nor sugar added (which makes you want to eat more I guess)
3) even dressing is bad, so raw is best to have a natural negative feedback system
4) even the most mundane raw veggies have a lot of flavour.. I eat carrots like M&M's nowadays, it's sweet. Same for lettuce or tomato. I really think modern western culture is hurtful there.