I don’t think those situations are analogous. The coworker has legal access to the same building and facilities that you do, and every legal right to be there. I would argue that it is reasonably foreseeable that a coworker might eat food left in the fridge; it happens all the time.
The burglar has no legal right to be in your home, much less help himself to your food. Arguably, it is not foreseeable that a burglar would break in and eat the Donut Of Death. Of course, on the other hand the homeowner’s action itself argues in favor of foreseeability: if the homeowner had not foreseen the burglary and considered it possible, if not likely, he or she would not have left out the DoD. But the owner could say he or she did it just on the off-chance the burglar would come, not because he or she really thought the burglar would.
I also don’t think it’s analogous to man traps, which are intended to either injure/kill the intruder through active means (the classic cocked gun tied to the door, set to fire when the door opens) or by passive means that do not require the burglar’s active participation (falling into a pit). Nothing compels the burglar to eat the DoD just because it’s sitting there; it’s not as if the homeowner has arranged for it to be fired into his mouth. So to me it’s more analogous to a trap door activated by a rope: the burglar must not only position himself over the trap door (by breaking into the house) but also actively, himself, pull the rope, which nothing compels him to do.
While you are correct that planning and intent are very important in criminal cases, in most U.S. jurisdictions a charge of attempt also requires that the defendant take some substantial step towards the commission of the crime. In this hypothetical, the homeowner has done nothing more than leave out and available the means by which the burglar can harm himself if he chooses. (And while the self-harm would not be knowing, consumption of the donut would have to be.) I have trouble seeing that as a substantial enough step to support a charge of attempted murder.