Some mornings I make porridge with around 30g ish of oats, a banana and raspberries/rhubarb etc

Whe I eat this I find I get hungrier earlier on compared to eating eggs or a gluten free weetabix made from sorghum.

Why do oats make me hungry?

I don't think I could increase the portion size as I'm full up after eating this and don't do anything different exercise wise to the other days.

Thoughts?