I have had many roommates over the years, and I inevitably come across people who like to dig into my drinks and eats when I am not looking. In an effort to not be overly anal, I have always allowed it, but it can be quite annoying. When do I draw the line? Can I say something? Or am I supposed to play dumb and just continue to finance my roommate’s eating habits?—Sulky Roommate

Dear Sulky Roommate,

If your roommate pilfers your food on a regular basis, you should say something. But it’s important to be careful about how you bring the matter up; your roommate might get defensive or deny the theft. To avoid a row, follow these rules:

1. Avoid specifics. Don’t complain about the loss of a particular item. You’ll look petty, or, worse, you’ll sound like one of the Three Bears (“Who’s been eating MY porridge?”).

2. Shame with generosity. Try this indirect approach: “I notice you’ve been eating my stuff. I don’t blame you, because I get really good stuff. All I ask is that you leave a bit for me.” Your roommate ought to feel too guilty to plunder your pantry again.

3. Disguise blame as recommendation. For example, you might say: “I see you like my brand of organic tortilla chips. You can get them at the health-food store near the fat-free refried beans.” (This ploy works only if the food in question is unusual. Otherwise, you’ll sound sarcastic, as in: “I see you like my Skippy. You can get it at the corner store.”)

4. Rise above revenge. Robin Honan, a documentary film producer in New York, recalls, “I drank some of my roommate’s ginger ale. She didn’t say anything about it, but a few weeks later, my honey bear went missing.” The kidnapping taught Honan a lesson. She won’t touch the ginger ale in the future. But the vengeful act made her mistrust her roommate (even after the bear mysteriously reappeared).

When should you overlook your roommate’s behavior and when should you speak up? Ideally, a roommate should avoid your food altogether, except in an emergency. If a 2 a.m. attack of the munchies strikes, you should forgive a roommate for ransacking your side of the refrigerator, provided that he or she follows these rules:

1. Ask first or leave a note. If you borrow a sweater from your roommate’s closet, months could go by before she realizes it is missing. But if you take her can of Diet Coke, she’ll definitely notice. Even absent-minded types retain a mental inventory of their food. (Perhaps evolution honed this ability, since in prehistoric times you starved if you forgot where you stashed your mammoth carcass.)

2. Leave one last helping. Only take the other person’s food if you can leave a serving-size portion of it. If there are only two Oreos left, you’ll have to schlep to the 24-hour convenience store, or go hungry.

3. Get a replacement. There’s no need to replenish something if you take a tiny amount on a one-off basis. For example, if you use a splash of milk on your cereal, you don’t have to buy a new carton. Otherwise, always replace anything you consume. Better yet, do as Honan does: replace it quickly with a larger size. If you’re lucky, this may even win points. That way, when you need to tell your roommate to turn the music down or empty the cat’s litter box, you’ll have bargaining power.

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