Crazy Consumption

When someone's mental instability, or at least separation from the rest of humanity, is demonstrated by their consumption of food in an unusual manner. Related to Big Eater, Extreme Omnivore and Masochist's Meal. Not to be confused with Conspicuous Consumption or the disease formerly known as consumption.

Examples of Crazy Consumption include:

Anime and Manga

Alucard from Hellsing. So long as Integra orders him to kill, he'll do whatever he damn well pleases to his victims. Including tearing off their heads and letting the blood pour into his mouth. And using demon dogs to eat them alive. Honestly, this guy acts more like a cannibal than a vampire.
- The Nazis basically spent an entire chapter messily devouring whatever the hell they could get their hands on. Including babies.
L and Mello from Death Note, and Light whenever he "take[s] a potato chip and EAT[S] IT!"
Anemone and her jam in Eureka Seven. The way she eats it is... disturbing.
Goku and Gohan (possibly all Saiyans?) from Dragonball Z are pretty crazy eaters.
Gintama : Hijikata Toshiro will put a big serving of mayonnaisse on everything, and Yamazaki has recently become an anpan junkie.
Yami Bakura from Yu-Gi-Oh! eating a steak like he's some kind of carnivorous animal. This was also covered in Big Eater.
Xerxes Break in Pandora Hearts. He'll steal your cake and EAT IT!.
Kumagawa Misogi in Medaka Box can eat taiyaki while making it look like he's just slaughtered somebody.

Rorschach from Watchmen eating cold beans straight out of the can.
- Fine like this.
  - As well as straight up sugar cubes. One gets the impression he doesn't actually sit down for a decent meal and instead just goes for high energy products.

In the backstories of both Aeon Natum Engel and its rewrite, Aeon Entelechy Evangelion, Misato Katsuragi suffered brain damage that left her with almost no sense of smell or taste. Thus, she has to spice her food to near-toxic levels to be able to enjoy it...and almost always forgets to make separate portions for anyone else she's cooking for. She also uses this to win bets on who can eat the spiciest food.

The main character in the movie Elf has an extreme Sweet Tooth, to the point where it is rather disgusting to normal people, piling on candy, syrup and sugar with joyful abandon.
In K-PAX we saw Kevin Spacey as the title character eat a banana without peeling it several time through the movie.
- Less noticeable but along the same lines, strawberries complete with the leaves.
Allison, the basket case from The Breakfast Club, with her throwing the baloney from her sandwich on the ceiling and replacing it with captain crunch and pixie sticks, as well as exploding her soda and licking it off the desk.
Used with the Mayor in Cloudy with a Chance of Meatballs, who is often seen over-consuming the various falling foods, until he becomes a Fat Bastard. In one scene he even stuffs a hot dog that is as tall as he is into his mouth in one go, freaking out the other characters.
In the 80's remake of The Fly, the first sign that something is wrong with Brundle is when he starts eating huge quantities of sugar and sweet foods. Of course when he starts spewing bile on his food before eating it, it's a sign that things have gone further downhill.
In Michael, the titular character heaps insane amounts of sugar into his food to experience the Earthly pleasures of sweetness.
Beast in Beauty and the Beast eats really messily to show how much of a beast he's become.

Kockroach from Kockroach really likes ribs. He eats them while naked, rubbing them on his chest.

Walter, from Fringe. He has a severe sweet tooth, and relies on Congruent Memory to help him recall projects he worked on long ago, triggering it by eating the same foods. This has occasionally led to him buying (or having Peter or Astrid buy) multiple brands of a single item trying to find the one that tastes the most like some discontinued brand.
- Also the Observers: One of them dumps an entire shaker of pepper and bowl of jalapenos onto a sandwich before eating it. They have almost no sense of taste and have to compensate by massively overspicing their food.
In the Doctor Who episode "The Eleventh Hour", the newly regenerated Doctor rejects some perfectly ordinary food before settling on fish fingers dipped in custard.
- The Master's ravenous appetite in The End Of Time.
- The second Doctor and Chessene in The Two Doctors.
Cookie Monster from Sesame Street.
An episode of CSI featured a man with a compulsive eating disorder - he was permanently stuck in a state of ravenous hunger because his brain couldn't tell if he was full. He had to spend his entire life restrained and guarded by caretakers, otherwise he'd eat everything - even the inedible.
In an episode of Law & Order: Criminal Intent, a character's mental problems are signposted by his habitual yet uncharacteristic eating of candy.

One of George "The Animal" Steele's gimmicks was to tear open a turnbuckle and eat the stuffing (see the page pic).

The Ravenloft supplement Van Richten's Guide to the Walking Dead details its authors' encounter with the Glutton of G'henna, an undead priest cursed with an insatiable appetite. He'd eat food by the wagon-load if it was available, but would gobble up whole livestock, chomp on the appendages of attackers, or even take bites out of trees, if that was all he could reach.

In Shadow Unit, increased food consumption (to fuel accelerated brain functions) is one of the telltale signs of a gamma. This applies to betas as well.

There was the CHOOOOOOOOCOLAAAAAAAAAAAAAAAATE guy from the one episode of SpongeBob SquarePants. You never see him eating any, but he was pretty crazy about it.
In an episode of Teen Titans, Cyborg gets a virus that makes him see everything as some sort of delicious treat.