It sounds like my place, what with the hot chips and glazed donuts left lying around on the kitchen benches. Besides the donuts, someone will regularly leave a spare hot pie or sausage roll there, or even a box of uneaten pizza in the fridge (Mmmm, cold pizza)
YMMMV, but what I do is generate a short-term but intense dislike of whatever food is tempting me. Almost to the point of anthropomorphising the item as a sneaky, poisonous little bugger really to fill my veins with fat, overload my blood with sugars and cause me no end of preventable health problems later in life.
If that doesn't work, I apply some sort of logical argument to talk myself out of it. For example, there's an economic term, "sunk cost", that sort of means that an item may have been purchased but if it no longer serves a purpose then it is actually worthless and should be written off. So I write-off the food.
There's also that wonderful feeling that comes later when you realise you resisted temptation by ignoring the donuts or whatever. And each time that happens it becomes easier.