I'm now (thankfully) self employed, but every office I've ever worked in has had the following Christmas Snack Police:
The Sanctimonious One
Nothing will ever be healthy enough for her. Even a bag of satsumas gets a tut because snacking between meals is bad for your teeth. Bringing in a tub of Celebrations is the moral equivalent of pushing crack to children. For bonus points she will in any event be gluten free, dairy free, sugar free, palm oil free and enjoyment free.
The Dieter
Christmas is coming, and she's not getting fat. She is on the fourth of her four annual diets (first quarter: self-denial and misery; second quarter: no-carbing before the summer holiday; third quarter: blood type diet, fourth quarter: the "thin before Christmas" plan she found in a magazine.) She can tell you exactly how many calories, grams of carbohydrate and Syns are in a Terry's chocolate orange, and she will. At length.
The Mrs Doyle
Oh, she really, really mustn't. OH, it's so bad for her, and OH so naughty. No, really, honestly, she shouldn't, she already had half a chocolate digestive three years ago. Oh they do look nice though, and it is Christmas after all.... oh no, she mustn't, really, oooh take the temptation away. Oh. Go on then. Just the one. [repeat forever]
The Beady Eyed Observer
Her face moves only imperceptibly but she is counting those mince pies. She knows exactly how many items there are in any box of treats and has already done the mental arithmetic to work out how many that is for each person. She's also keeping a silent tally (possibly a spreadsheet) of who bags the 'nice' treats. She'll harbour this knowledge forever. Possibly on spreadsheets.
The Hoover
She has no control and gives zero fucks. It's Christmas. For two weeks of the year she can gorge on cheap chocolate, and this is presently the only thing stopping her from stabbing The Mrs Doyle through the eye with a letter-opener. The Sanctimonious One and The Dieter aren't eating them anyway and she secretly enjoys watching The Beady Eyed Observer silently twitching every time she reaches for another chocolate almond. It'll get her through until home time when she can be reunited with her functional alcoholism.
The Desk Tidy
A constant well of efficiency, she is the only person who can defeat the Hoover. She will wait until everyone has had a single treat, which means she has to go and listen to the tedious self-persuasion from Mrs Doyle, and then brightly announce that these should be tidied away now. Vaguely connected to a failed affair with a French philosopher, her motive for tidying away cake until it goes mouldy and has to be thrown away before the disappointed gaze of the Hoover is a mystery even to her.