You've entered the world of shared living, if it isn't this issue, and this chap, then it will soon be someone and something else.
It may be awkward, and no matter how you approach it it probably will cause a little friction, but if you really don't want to lend your stuff out, you just have to bite the bullet and say so.
The laptop / expensive stuff aside. I'd advise you just let the cutlery, bread etc go. Sharing a house / halls is MUCH less stressful when everyone knows they can use whatever they need, and everyone has got to the point of respect where everyone pitches in and nobody takes the ****.
It's amazing, but letting these things get to you can really do your head in. I've seen best friends fall out for ever. Major strees for disproportionate problems when you think about it.
Sometimes you end up living with a maniac. Not much you can do about that until you / they move on.