Firstly, can I just chip on on the eggs issue you just mentioned?
The fact that eggs cause high cholesterol is actually a myth! Due to research carried out in the nineties (I think it was the 90's..) and the results misconstrued in the media. The cholesterol in eggs is different to humans and can not be transferred - they're completely fine to eat!
Next.. regarding the whole Smash pizza debate.. I think it's quite easy to work this one out logically. Think about what you are eating - is it adding more to your plate? Are you having chips with your pizza? Would you usually eat a whole packet of Smash in a cottage pie and then add the same amount of chips you're going to eat with the pizza? If your quantities are still all the same, your plate is still a third superfree and you're satisfied equally (or more) then no harm is being done really is it?!
My tuppence, although this is just fuel for the fire I guess... always drink a glass of water with your pizza (or before it) as liquid, when in the stomach, tells the brain it is fuller for longer. I imagine that because you're using a lot less water to make the mash, you're going to get hungry quicker afterwards.