“Garnet likes to eat sometimes”
In “Keystone Motel,” Greg had the following quote:
However, we have NO EVIDENCE in the show that Garnet likes to eat (as of the day I’m posting this in April 2017). In fact, literally every time she’s presented with food, she doesn’t interact with it or eat it, and never acts like she cares about it. Pearl makes a big deal about not eating, but Garnet’s eaten in the show as often as she has: ZERO TIMES.
In “Together Breakfast,” she helps make the Together Breakfast, but seems uninterested in it. (Granted, nobody else eats it either.)
In “So Many Birthdays,” she doesn’t care about the birthday food.
In “Beach Party,” Garnet sits in front of an untouched hot dog and comments that they don’t need to eat.
In “Warp Tour,” she bakes cookies but has no intention of eating them herself. They were intended for Steven, but Amethyst eats them.
In “Bismuth,” Pearl doesn’t bother to get a plate, but everyone else has pizza, and Garnet alone isn’t eating it.
And in “Gem Harvest,” Garnet doesn’t partake at the feast.
The closest we get to Garnet eating something in the show is from a scene in “Secret Team,” when it’s strongly implied that she drinks a sugary soda drink with Steven. When she arrives at Fish Stew Pizza, Steven has ordered drinks for them. You can see Steven has sipped some of his while Garnet’s is full.
Then she picks up the cup like she’s going to drink from it, though you don’t actually see her do it.
And then you see her set it down, with the liquid in it diminished. She probably drank the soda.
Though the sodas are back to the levels they were at before the next time we cut to a side scene of them, so who knows. There was also another time she ALMOST ate, in “Back to the Barn.” She was about to eat popcorn:
And then she literally shook her head and didn’t eat it, like she’s trolling all of us who want to see if she eats.
Garnet canonically eats multiple times … IN THE COMICS.
In “Doppelganger,” a short in the original comic run Steven Universe #4, Garnet eats a double-scoop ice cream cone while hanging out with Steven.
In Steven Universe and the Crystal Gems #1, Steven teaches the Gems about roasting marshmallows over a campfire, and Garnet plays along, happy to eat the marshmallows.
And in the 2017 ongoing comic series, Steven Universe #3, Garnet is seen in the background of a crowd scene apparently eating or about to eat a donut. (I assume it is a donut, not a bagel, because Beach City businesses are offering their specialties here and the Big Donut is included.)
What do all these instances of comic-book eating have in common?
THEY’RE ALL SWEETS.
OBVIOUS CONCLUSION: GARNET IS A SUGAR FIEND.
This theory may be further supported by the fact that she was the only Gem able to make an acceptable cake for Steven for his birthday in “Birthday Bake-Off,” a short included in the original Steven Universe comic run, #1. Amethyst and Pearl had failed to make edible cakes, and then Garnet shows up with this:
Aaaand it’s not even really a cake, just solid icing.
I hope that when and if she actually does eat in the show, it will be sweets.