Well we’ve moved four times since Y2K and that food wouldn’t have lasted that long anyways so yes it had to be thrown out.

Why didn't you eat it? Why throw it out? you must be flush with money.

Why anonymous? Is this something to be ashamed of?

I do not store a lot of food, though I might buy packages that will last us quite a long time.

It depends on what you have stored. I would never discard food just because of a totally arbitrary date stamped on packing.
 
I have even purchased so-called out-of-date food and eaten it.

Opsec??
Never count your money at the table.  Glad I learned that lesson well.  

I stored mostly canned food and plastic spoons.

You don't need heat.  You don't need water.  You don't need clean dishes.  Just open and eat.  And it doesn't go bad for years.

I bought extra can openers too.

I tried to focus on protein so chili, beans, stew, tuna, vienna sausage.

You can live just fine for the rest of your life never eating another carb.

Without protein you die.

Protein and fat fill you up and keep you full much longer too.

A spoonful of peanut butter can go a long way so I bought a few jars.

Also, when rationing, it's better to fast and feast.

No food for a day or two and then feast. 

That's much easier and healthier than eating a little each day.

Agreed.  One thing that irks me with all of these bulk-prep-food companies, is that they are basically selling huge cans and buckets of carbohydrates.  Really, in a crisis, are you going to have the wherewithal to make pancakes?  Those ads make me a little queasy just looking at them.  

If the Mormons store this kind of food, and rotate it, then that's an awfully starchy diet.  I'll pass, thank you.  My modest food-storage program, if it can be called that, focuses upon protein and canned vegetables.  A can of corn, or a can of peas, emptied into a plastic container, salt, pepper, and butter, and heated in the microwave for two minutes, fills out any evening meal with something very good for you.  I've made many a meal out of leftovers that way.

“Shelf life” often has more to do with quality (both nutritional and palatability) than with safety.  Still, rotating food stocks is a good idea … ageing usually only works well for cheese and wine.
 
Unfortunately, foods that store well for emergency use are often not idea choices for daily meals (because of taste or cost), and don’t always work well into a regular rotation.  For example, I at least hugely prefer fresh and frozen vegetables over canned.  Canned (or tinned for some) meats and fish can produce very tasty meals but these are often more expensive than buying fresh meat or fish on sale and freezing some of it.  The freezer is not the best choice for storing emergency foods unless you have a generator, as the electrical grid may go down … unless you live someplace like Minnesota, where during the winter you can put the freezer contents outside.  Dry goods such as pasta, rice, quinoa, lentils, beans, flour, salt, sugar, and dehydrated products like potatoes, soup, gravy, and sauce mixes, are great items for an emergency pantry and normally rotate well into a regular menu, so it is easy to keep the stock fresh and current.
 
To avoid having emergency food items you wouldn’t normally use becoming stale, “expired”, and loosing nutritional value, consider a rotational donation to a local food bank, where they will quickly go out the door and into a meal.  I realize that some here wouldn’t want to “go there”, but the local diocesan parish may have a St. Vincent DePaul Society conference, I would think that would be a better option than the Salvation Army (vehemently anti Catholic), some other protestant group, or letting things go to waste.  Many communities will also have secular food banks and emergency food distribution systems that need donations.  Better yet, a traditional chapel of some size and stability could consider setting up a food and clothing bank along the St. Vincent DePaul model.  The Corporal Works of Mercy and Our Lord’s words in St. Matthew 25:35-45 are still very much a part of the Catholic Faith.
 

really old canned food begins to taste really tinny.

If you have too much canned food to eat in rotation, or some slip through the cracks and got really old, consider keeping meat animals of some kind and feed the expired food to them.  

Be sure to check your peanut butter; it will go rancid

Peanut butter powder is widely available.