I don't know the motivation but it's a common problem for some reason. I worked at one place where it got so out of hand me a few other co-workers got fed up and spiked a bunch of our leftovers with brutally hot habanero sauce and left them in the fridge in the lunchroom. It worked.

I worked at a place where one of the senior leaders stole a temp's lunch and completely denied it, despite the sandwich being on his desk.

Its so shameful.

Back during my Ph.D. days people stole coffee capsules from others. I remember having a few in my drawer, only to find none the following morning.

It can be mind-boggling, but it definitely happens.

Can't compare coffee capsules to food you cooked yourself.

If they were in his drawer though...

I don't know what it is about office spaces that causes latent kleptomania to surface with such regularity.

That was just the tip of the iceberg though. That place had some serious thefts going on. Once, a group leader's iMac was stolen one day: it was tied to the table with a Kensington lock, but the chain was just sawed off...

This sounds like a call center or similar place where they're desperate to fill the cubes with as many warm bodies as possible, sociopath or not. The behavior of HR suggests a less than professional workplace with high turnover.

I heard about this at my wife's former workplace that there was a food thief haunting the break room fridge. It's nuts but really happens.

"Sorry boss, I have stomach issues I need to take a laxitive but the taste makes me sick so I mix it with my lunch, heres my prescription, by the way and on an entirely unrelated note...has anyone seen Peter this afternoon?"

I work in a shared working space, it's just me using my stuff yet the amount of milk, tea bags and sugar I get through and have to keep buying... Even tried labelling it yet people just to go to fridge or cupboard and help themselves... It's so annoying.

To be fair, if I saw milk in the fridge of a coworking space, I would guess it was communal.

At the coworking space I frequent there is a small bucket and a sign, when people take some sugar or a teabag or whatever they drop a quarter or a dime in the bucket. Whenever the space is out of teabags someone empties the bucket and buys some.