Katy Perry -- Backstage Demands ... Let Them Eat Rabbit Food!

Katy Perry made a slew of backstage demands for her New Year's Eve concert in Vegas ... crazier than Mary J. Blige's proviso requiring a new toilet seat for each venue.

TMZ got hold of the deal Katy cut with Caesar's Palace ... and her demands for backstage catering read like a farmer's market shopping list.

-fresh veggies AT ALL TIMES -- including spinach/broccoli/celery/beets/carrots/kale, etc.
-two large baskets of fruit -- one must be tropical.
-dinner must include a vegetarian option ... plus quinoa or couscous.
-ALL meals must be low-fat and health conscious and cannot contain MSG.

Katy's dressing room requirements are even more specific:

-fresh organic grown fruit (including SLICED pineapple, mango, kiwis, etc)
-fresh cut crudites (cucumber, broccoli, cauliflower, carrots, snap peas & celery ... plus ranch dip)
-healthy granola
-dried figs
-whole grain tortilla chips
-large bowl hummus
-fresh made guacamole

Katy also likes fermented grapes -- 2 bottles of Pinot Grigio and 1 Argentine Malbec.

Someone needs to tell her ... wine is a gateway to the path of evil ... lined with Cheetos and pizza.