We don't overthink this issue having crossed the border both ways for over 10 years. Before we cross, we run down our supply of food at home and pack what's left in the fridge in the RV. We answer the questions at the border and if some stuff gets taken there it's not a problem (since we pay per bag of garbage at home, it's a benefit to have something disposed of at the border free!).
You are at the mercy of the agent at the border though, we once had a bag of dog food taken because it "could have been packed on the same line as product with beef in it" during a beef embargo. We needed to shop immediately at our US destination to feed the dog.
