Some foods can have addictive properties...they cause chemical responses in the brain in the same way as alcohol, tobacco and drugs such as coke. There are individual ingredients such as grains and sugar, and the combination of certain fats and sugary carbohydrates.
That you don't feel satisfied is your brain telling you to eat more, not actual hunger. Include a bit more protien in your meals plus healthy fats...both will be more satiating.
I speak from experience...I very rarely eat bread. In the past I could easily scoff 5 or 6 slices...and still want more. I ate a LOT of bread.