Dozens of melon-breads, no pounds gained. What is her secret?
Some of the Saiyans (Goku, Vegeta) and half-Saiyans (Gohan, Goten, Trunks) in Dragon Ball. The funniest part is that the other characters always look on in shock no matter how many times they see it done. Though their reactions could be due to the eaters' less-than-proper table manners, since they all seem to snarf down the food as fast as possible. Goku doesn't even let being dead stop him from chowing down, to King Kai's eternal confusion. One character even commented that Goku seems to be able to eat more in one sitting than his stomach could logically hold. Though it's mostly played for laughs, the Saiyans might arguably be a case of Justified Trope when you consider just how many calories their bodies must burn with all that muscle, much less the fighting.
The villain Bills from "Battle Of Gods" is also a really big eater and he's much skinnier than Goku.
It's something of a running gag, as Tien, Yamcha, and Chiaotzu all eat similar amounts of food on King Kai's planet.
Hei from Darker Than Black is both an excellent cook, and known for eating a ridiculous number of servings◊ per meal. Granted, he probably burns a lot of calories due to all the super powered contractor fights he partakes in, but still. Since he's a Contractor, it initially seems that his eating habits are his Remunerationnote a bizarre, obsessive compulsive "payment" Contractors have to perform after using their powers; examples include: breaking their fingers (ouch!), smoking a cigarette, arranging pebbles in a pattern, writing bad poetry, drinking warm milk, etc, etc., but it turns out that, nope, he just really likes food. Misaki Kirihara isn't quite as bad, but does eat a lot as well (and likes fried food), which she justifies by claiming she gets lots of exercise as a cop. Gets taken over the top when the two of them have dinner together.
Charles Grey in the Black Butler manga managed to eat Earl Phantomhive out of house & home, with 34 dishes piled high.
Sket Dance's Chiaki Takahasi, Captain of the Kaimei High Softball Team, will eat absolutely anything and everything, as long as it's edible, IN RECORD TIME. Okay, almost everything. She has a weakness to eggs, which she absolutely despises.
Pokémon: Ash and his friends have been known to fall into this category every now and then, usually when sitting down to an extravagant meal put on by some gracious host. (Or from Brock, who fills the role of the Team Chef and is very good at it.)
Ash definitely falls under this. Most episodes he complains that he's hungry, one of the running gags is his stomach always growling (Misty would often go, "Not again!" at this. Later on when this happens, both Brock and May remark that "some things never change"). When he gets food, he really stuffs himself. This has been lampshaded on a number of occasions. The beginning of one of the Johto episodes has him suffering from a belly-ache due to eating too much, and after about 400-something episodes, gets his first Balloon Belly scene in Sinnoh.
Despite how much she teases Ash for it, May might actually be worse. And Arceus help you if you try to take her share. On another occasion, she was even bribed with her favorite food (noodles) to help settle a family squabble that Ash and company would otherwise steer clear of.
Team Rocket, when they're lucky enough to have enough to pig out on. Once resulted in a fat episode where they had to work it off.
The Pokemon themselves are not exempt from this. Dawn's Piplup was frequently hungry, and Clemont's Chespin is such a glutton that, like Team Rocket, he had his own fat episode.
Kagura from Gintama is constantly snacking on sukonbu. She also eats so much that Gintoki once used her to get out of paying a bill at a place running an "Eat XX amount in XX minutes and it's free!" promo. Gintoki himself is a sugar freak who only cuts back because his doctor told him he was on the verge of diabetes.
It's only once made a plot point, but any time Simon or Kamina of Tengen Toppa Gurren Lagann sit down to eat, they generate a tremendous pile of dishes. Kamina even declares that "A man's stomach knows no limit!" in Episode 6. It shows, too.
In Episode 4, it's shown that they have to eat something in order to generate Spiral Power. They survive the enemy for that the episode only because Boota willingly tears off his own tail and hindquarters to feed the two.
The eponymous Toriko embodies this trope and then some. A meal that could satisfy 500 people only filled him up 1/10. ONE TENTH, for a 500 man feast. Though this is kind of typical, as he has ridiculous amounts of strength and endurance, and he originally was a hybridized animal.
In the first chapter, after Komatsu asks Toriko to help him capture a Gararagator, the two of them head to the docks and have one of Toriko's friends sail them to the island. Along the way, Toriko digs into numerous meals. Komatsu shouts that he's been eating endlessly for six straight hours.
Zebra actually managed to eat 26 species into extinction.
The reason so many in this series are big eaters are due to having a unique cell in their bodies which increases their power but have a huge demand for energy (i.e calories). The amount of calories Toriko needs to function day to day is 100,000 calories, 50 times that of a normal human. He can hold millions of calories in his body but if he doesn't eat at all for even a day his body may start eating itself.
As of Chapter 275, the yet unnamed cat-spirit that haunts Nagi's new apartment wolfs down Hinagiku's cooking while inhabiting Izumi's body. It's yet unknown what effect exactly this will have, but we now have the opportunity for another big eater.
Eyeshield 21: Otawara eats a ton but is almost pure muscle. With Popeye arms. Ikari, Otawara's teammate, is a Big Eater himself, but while a tough, muscular guy, is built pretty slim.
Edward Elric from Fullmetal Alchemist tends to do this, all while also eating his brother's share due to a certain handicap in that area. It's speculated by Ed himself that this he might be eating to support his own body and Al's real body which is caught in the Door of Truth.
Saya Otonashi of Blood+ has this to the point that her brother Kai regularly refers to her as a glutton. It's actually an example of Fridge Brilliance: Saya only receives enough blood through transfusions to remain healthy, but her body still needs more energy, and human food doesn't quite match up to blood.
An unusually dark example is in Drifting Classroom. Nakata is an insatiable eater. The problems: first, they're in a post apocalyptic wasteland with no way to get more food, so his eating is causing others to starve. Second, when he eats he summons an invincible gigantic insect monster that tries to kill everyone.
Chizuko from Mahoromatic is the smallest of the schoolgirls, yet she has a near-bottomless stomach.
Horo from Spice and Wolf doesn't wolf down an unrealistic amount of food like some of the other examples as fitting the more serious tone of the series, but she will eat herself sick if she's got enough apples and in the novels she loves cookies. She's had serious hangovers more than once, too. This is all because she doesn't know her limits to eating while in human form. Like many people often do sooner or later, she finds herself pushing to the limit of how far she can go just because she doesn't know when to stop.
Fuu of Samurai Champloo. She outdid every other contestant in a eating contest including fellow good eater Mugen, except for one, and only lost because of an unfortunate mistake she committed, accidentally signally that she conceded when she actually had plenty of room for more. A rare example of this trope, her appearance changes according to what she's had to eat recently. Usually she's slim and flat-chested, but after going all out on free food she gets Gonk levels of lard on her, only to lose it in a matter of hours, and start complaining again how hungry she is. Her metabolism is a frightening thing to behold.
Although it's presented as a sight gag, in one episode a group of thugs were searching for her because she had been spending counterfeit money her group stumbled upon in the woods, but by the time they crossed paths with her, she had bought enough food that she no longer resembled her original description. Fuu actually felt a little insulted when they overlooked her, but she knew well enough to take advantage of her temporary blessing and went further into hiding.
Uehara in Good Morning Call. The first meal we see him eat is four pizzas, all in one go.
Legato Bluesummers from Trigun is a relatively rare villain example. Word of God says that this was intended to be a humorous character trait, but also serves to make him creepy depending on the context of the meal.
Aisha Clan-Clan and apparently all Ctarl-Ctarls from Outlaw Star. In the first episode showing her tangle with the heroes, she's seen vigorously stuffing her face at a restaurant, including chugging multiple bowls of stew—each of which were large enough to feed a table of four. Her appetite happens to fuel her super-strength and ability to turn into a feral tiger-creature, and she can be weakened by not eating. Her food tabs are a pretty sizable addition to the crew's financial woes.
Lina Inverse, Gourry Gabriev, Amelia and, in the anime, Pokota in Slayers. Justified in-universe as the more you do, the more you need to eat to sustain yourself. As a result, spellcasters need to take in lots of energy to counteract the drain of the spells they cast, and Lina is extremely careless about slinging spells around. Gourry's hyper-swordsman skills (and his own considerable stature) take up a lot of energy for similar reasons. The only exemptions are Xellos, who is an Emotion Eater, and Zelgadis, who usually eats less due to his nature as a Chimera — being one-third demon and one-third rock golem means he needs less physical sustenance. The one time he does eat like the others is to enjoy a victory feast for killing Copy Rezo and Zanaffar at the end of the first season.
Usagi (and sometimes Chibiusa) from Sailor Moon. Only one episode early in the first season ever concerned itself with her possible weight gain and that was dealt with as a Compressed Vice. Sailor Moon Abridged plays this aspect up as a Running Gag, where Usagi is constantly called fat even though her character design is far from it. Her younger brother Shingo was sometimes said to be this too which makes sense since as an adolescent he's got some growth spurts to fuel (one of which appears to begin at the start of the second season).
Ranma Saotome is a borderline case; he does eat large meals, and is willing to swindle or steal food if particularly hungry, but the fights he gets into presumably burn a lot of calories and his meals aren't exceptional by ordinary standards. When he's been really pushing himself, however, he eats a lot more to recover (one anime episode has him consume five heaped bowls of rice after spending 72 straight hours doing nothing but train), and he can put away an impressive amount of food if pressed (an anime episode has him consume four full-course meals as part of a contest).
The OAV Akane and Her Sisters introduces Kurumi "Tendô", who put all Big Eaters in the series to shame. Despite being a small girl, she can wolf down record amount of food faster than any martial artist. She's also an Extreme Omnivore, able to eat Lethal Chef Akane's cooking — and ask for more.
There's also minor character Picolet Chardin II of the "La Belle France School of Martial Arts", which specializes in martial arts gourmet dining. Of course, one of the requirements of this form of martial arts is that you have an unusually flexible and large mouth capable of eating so fast you can't appear to be eating at all. By the standards of his school, being seen eating is considered "inelegant". Picolet, and others who specialize in this form of battle, are able to put away full course meals as if they were a light snack. Picolet once devoured an entire table of food and his instructor bemoaned that he had virtually no appetite anymore.
The titular Squid Girl from Shinryaku! Ika Musume absolutely loves shrimp and in one episode manages to polish off 10,000 yen's worth of shrimp in one sitting. Taken to ridiculous extremes in the "Mini Ika" episode, in which she devours shrimps several times her own size in a matter of seconds. Apparently she's able to adjust her own body mass at will, which explains why she doesn't get fat.
Sakura Sakurambo in Urusei Yatsura regularly puts away GIGANTIC servings of food, and despite that never loses her swimsuit model figure. This is first displayed in an eating challenge in Hawaii, where, despite having taken special diet pills, she effortlessly completes an eating challenge, to the point of forcing the restaurant to shut down permanently due to eating all of the food and sending them bankrupt from buying new ingredients, not to mention sending the cook staff weeping in utter defeat. In the anime version, this culminates in her not only asking for dessert (after having polished off a final course consisting of, in order, a whole roast turkey, a whole roast pig and A WHOLE ROAST COW), but then asking for the teens who didn't attend to bring her some Chinese food when they fetch dinner. In the manga, she goes to take a nap in the pool after the contest is over, causing the inflatable mattress she rested on to sink, despite not having gotten the Balloon Belly that Ataru and her uncle Cherry had received from their participation in the eating contest.
Goku in Saiyuki. Sanzo suggests this is justified because Goku was locked up in a cave for 500 years without food.
Miaka Yuuki in Fushigi Yuugi takes this to quite the extremes. When the antagonists use food to lure her into traps twice...
Tamama in Sgt. Frog has, on countless occasions, been shown eating an amount of sweet and snack foods that's bigger than he is.
Monkey D. Luffy. Potentially justified in that A) the fighting he does would require a lot of energy, and B) that his elasticized stomach is capable of storing far, FAR more food than a normal human's. At one point, he wakes up after passing out and instantly knows exactly how many meals he missed, (5 per day, apparently) and later gets around this issue by somehow managing to eat while sleeping.
It's probably also fueling one of the Required Secondary Powers, seeing as he seems to be able to stretch several times the distance of a football-field and is often extremely hungry after any battle, where he always stretches as part of his battle-style. This way of eating also applies to drinking; he can drink so much he should have water-poisoning.
The most extreme example from One Piece would be Wapol, who has eaten a Devil Fruit that allows him to eat anything! Every time he's seen, the only thing near is other people or he's eating something, including things like houses or cannons. Also, he eats other people if he wants to. When the Straw Hats first meet him, he starts munching on their ship. When he got his own cover-story, he was eating entire villages. He can even eat himself, which makes him skinnier.
Big Mam of the Four Emperors. She eats 10 TONNES of candy every month from Fishman Island alone. She'll even eat her own subordinates if she gets hungry enough and unlike Wapol, these guys stay eaten.
Yukito Tsukishiro and Keroberos, from Card Captor Sakura. Yukito's excuse is that his body tries to compensate for not having a source of magical power, and later Sakura not being able to provide enough magical power to keep him in existence due to her extreme youth, while Keroberos just likes to eat. Sakura's mother Nadeshiko was one too, being able to finish a large cake in one sitting despite being a frail girl.
Caren from Mermaid Melody Pichi Pichi Pitch has been shown to be a Big Eater in the anime. She was a jerk about it, too; when Lucia and company were trying to convert her to their cause, she simply used the opportunity to leave them with her bill.
Nozomi, Rin, Urara, and Karen from Yes! Precure 5. (For those of you playing along at home, this is half the main cast, and four of the titular five.) Karen is something of an unusual example, as unlike most Big Eaters she eats calmly at a normal pace. Urara is normally the undisputed queen, but Rin and Karen can both out-eat her when they feel it necessary (i.e. when they're trying to out-eat each other). Also, Komachi was a big eater when she was younger.
Taichi and all the Digimon in Digimon Adventure. Justified in case of the Digimon, since they need to have a minimal stash of energy to transform into their evolved forms; once Agumon attempted to digivolve on an empty stomach... and couldn't. While Taichi is a growing pre-teen/teenager and pretty athletic, it still doesn't justify the amounts of food he ate.
Kikuchiyo from Samurai 7; however, he is both the largest of the seven and, well, a cyborg.
Demons in the series Konjiki No Gash Bell eat their food whole, their head transforming into some strange eating machine as a result. Main character Gash is no exception, often eating poor hapless yellowtail tuna alive immediately after catching one.
Another Sakura: the one from Amaenaideyo. She eats enough food to feed the whole temple, and yet never loses her great figure.
Yako from Majin Tantei Nougami Neuro eats insatiably, despite being a small, teenaged girl — paralleling Neuro's appetite for mysteries. Her ability often helps solve crimes: her stomach is so powerful that she can eat any poison with no ill effects, and she can even taste how much "love" went into preparing the food.
Momoka in Touka Gettan. She first meets a couple of characters by eating their lunches.
Allen Walker in D.Gray-Man. Just look at how much food he orders when he first enters the Black Order...
Takeshi Momoshiro and Ryoma Echizen from The Prince of Tennis. Their friends and teammates shudder at the mere thought of having them tag along for burgers.
Ryô Saeba from City Hunter uses to eat huge "lunches" accompanied by two liters of eggnog.
Kurumi and Manami, Kyôsuke's sisters, in Kimagure Orange Road. Hatta and Komatsu truly didn't know what they were getting into when they asked the girls out for pizza. In addition to it, Kurumi is a Lethal Chef. It's another case justified by their Esper powers; the more they use them, the more they get hungry and need food to recover the energy. And since Kurumi tends to be very gung-ho in regards to her psychic skills...
Chiaki from Magikano. She talks and thinks about food near-constantly, and she fantasizes about living in a Gingerbread House full of sweets... however, she exercises near-constantly, too, and says that she likes to exercise even more than she likes to eat.
Shizuka Doumeki from xxxHOLiC is not only a Big Eater, but he's an extraordinarily picky one at that. Apart from demanding stupidly difficult-to-make dishes from Watanuki, he also adamantly refuses to eat anything made by someone he doesn't know or approve of. (His grandfather Haruka mentioned that it was nearly impossible to take him out to any restaurants because of this.)
Yuko from S.S. Astro. She brings multi-level bento to school everyday, and eats after every class.
Three female examples from Ikki Tousen: Hakufu, Ryuubi and Chouhi. Both Chouhi and Ryuubi do look a bit pudgier, but in Chouhi's case it's more likely to be muscle than fat since she's a Cute Bruiser.
Baki the Grappler once ate enough Chinese food to give him a Balloon Belly, and then 8 litres of sugar fruit mixed with water to regenerate his lost muscle tissue.
The eponymous Yaiba, together with Gerozaemon and Musashi, especially Musashi, during the firsts arc. Musashi in his first appearence was able to steal and devour a whole roasted boar in about two panels or so.
One of the few cases when this is NOT Played for Laughs is Kyouko Sakura from Puella Magi Madoka Magica, who eats a lot because of her Freudian Excuse: her family fell into poverty after her Christian Minister father was excommunicated, so they had almost nothing to eat for a long while. After said father lost his mind and then went the Pater Familicide route, Kyouko likely spend some time destitute as well.
It's likely she still is - she can't honestly tell Sayaka where she gets her food from. Being a very powerful Magical Girl with no qualms about being an asshole it's likely she steals the food.
Melan of Brigadoon: Marin and Melan sure can pack away the rice, eating gallons of it at a time. Makes a bit of sense: he's a cyborg who refuels with human food.
Kyosuke from Hentai Kamen is shown to have a comically tremendous appetite after wearing a particularly powerful pair of panties.
Junta from Ame Nochi Hare. His voracious appetite in virtually any situation is somewhat of a running gag.
Index and Aisa Himegami of A Certain Magical Index, although the latter is only a big eater when it comes to burgers. Index, however, will probably swallow a kitchen before being satisfied. Fortunately for her (and misfortunately for the guy), Touma knows how to cook.
JoJo's Bizarre Adventure plays this trope a bit more seriously than usual. In Part 2, we are introduced to the Pillar Men, an ancient vampiric race of superbeings that devoured other lifeforms. Eventually, their appetites grew too massive, and they would have consumed all life on Earth had they not come up with a way to create more satisfying meals. Namely, by carving magical stone masks and using them on humans in order to turn them into vampires.
Bleach has Yoruichi, who is shown in episode 114 putting away massive amounts of food. To put it into perspective, Urahara just quietly sits in amazement, watching Yoruichi doing nothing but gobbling down numerous bowls of food for about 3 full minutes completely uninterrupted.
Orihime, to a certain extent. Her friends lampshade it by saying that everything she eats goes to her Gag Boobs.
Played for horrifying effects with Liltotto Lamperd, Sternritter "G" of "The Glutton". She is always hungry and snacking on anything, becaue her power is to eat pretty much anything... which includes living people.
Nana from Elfen Lied thinks with her stomach and goes into a trance whenever food is mentioned.
Miharu in Girls Bravo never stops eating, or questioning whether newly discovered objects (for instance, butterflies) are edible.
Honey from Ouran High School Host Club can eat three entire cakes even after a full meal. It's also revealed that, once a week, he eats five cakes as a midnight snack, and later in the episode he decides to do so three times a week instead.
Tadashi from Special A is nearly always seen stuffing his face. Good thing his girlfriend's a Supreme Chef.
Bleed Kaga from Future GPX Cyber Formula eats anything (except for foods that are too sweet) to a degree. In one episode of Double-One, he eats an egg yolk before eating a piece of toast and in another on the same show, he eats noisily and fast.
Hana Isuzu from Girls und Panzer is subtle about being a big eater. She is the tallest in the cast, and no one directly mentions it, every time people are shown eating, Hana has at least twice as much food as anyone else. Its Probably just a high metabolism.
Wako Agemaki from Star Driver gets hungry easily and is never once seen to turn down food or a chance at a meal.
Itto and Mayu from Tokko eat constantly, even right at the beginning of a battle.
Karuta from Inu X Boku SS, almost always has some to eat in her hand if not she will.
In Saint Beast, whenever there's lots of food around Gai tends to stock up his plate immediately.
Renge of Airmaster is well known for this. Anytime she even sees Sakiyama, she will demand her to buy food. Hell, in one episode, she ate an entire bowl of rice in mere seconds and outate several adults in a food-eatting contest. The only thing that makes it over the top is that shes a small as a child despite being a teenager.
Akari's three cats from Sangatsu no Lion, most likely due to being spoiled with all the food she gives them, eat a lot of food. Ravenously.
Rather bizarrely, Ryu in Street Fighter V: The Animated Series. The series essentially transplants the canon Ryu's personality and installs that of an atypical Shonen Hero, including the voracious appetite.
Sasha Blouse from Attack on Titan to the point that she can't resist stealing and eating a potato during recruitment (which gets her punished). She even steals meat, which could get her into solitary confinement, just because she couldn't resist her appetite. This is because she nearly starved to death in the past.
Also used for horrifying effect with the Titans. All they do is eat people. And eat. And eat until what passes for their stomach is full, at which point they vomit and start all over again. They cannot digest or gain any form of nourishment from their victims, so they do it simply because they enjoy eating.
Genki Girl Yoko is probably one, seeing her finished up her lunch before school. That was on top of breakfast. She's taller and bustier than most of the cast, but is not fat.
Karen also has some shades of this, in fact, it's even stated she can eat a lot of food without gaining weight.
Mitsuba◊ from Mitsudomoe has quite the appetite. Case in point, during a party she ate her dinner faster than everyone else. She proceeds to ask for everyone else's food and ate everything she was given. And then she ate a whole tub of ice cream when she got home later that same night. While she's not really fat, her habits certainly show. And she hates it.
In GA Geijutsuka Art Design Class, Namiko's sister's Fujiko's first appearance at home has her eating the entire contents of the fridge, including what Namiko's intended lunch ingredients. School cafeteria workers noted when she was in school, they used one extra sack of rice a day... On top of that, she is flatter than Huge Schoolgirl Namiko.
Kyohei from The Wallflower is often heard asking where there is food, when the group is going to eat, or otherwise demanding Sunako, the Supreme Chef girl that lives with him and his friends, to make something. At one point in story he travels cross country using the money he wins from eating contests.
Ragnarok from Soul Eater seems to be this. He steals his meister Crona's food and constantly demands that Crona feed him more.
Aila from Gundam Build Fighters is this. Although we don't see her eat a large amount of food at once, most of her scenes outside of battles has her enjoying food. She has also been seen with a large bag of food which was implied she would eat all of, with her being offended for even losing a single meatbun from it. This takes a depressing turn when a brief flashback showed that she was a malnourished and homeless orphan.
Main character Tanikaze Knights Of Sidonia was often teased by the other residents of the Sidonia for having an enormous appetite... at least in their eyes. See, the Sidonia is a Generation Ship, and in order to conserve resources, the inhabitants have all undergone a treatment that allows them to Photosynthesize their food; they still need to eat every now and then, but it's not uncommon for someone to go an entire week without eating anything. Tanikaze, however, never received the treatment because he grew up in an isolated part of the ship away from the rest of the colony, thus he has to eat several times a day to keep his energy up. He does have a hearty appetite, but no more than what a person might have in real life.
Rize Kamishiro from Tokyo Ghoul eats so much she was nicknamed Big/Binge Eater in canon.
Yajirobe, the overweight samurai in Dragon Ball. He managed to kill and eat Piccolo's giant, dragonesque minion Cymbal, and still wanted more (he got upset when Goku's kamehameha burned Tambourine to cinders; there was nothing left for him to eat). Then he started chowing down on Korin's senzu beans to the old cat's shock. One senzu is supposed to keep you full for ten days. Yajirobe munched on them like popcorn.
Bob from Gungrave is constantly seen eating, usually a drumstick of chicken, and while he is shown as skinny when first introduced in the past, he steadily grows more rotund over the series as his habits catch up with him. After the series returns to the present, it's revealed that he ate so much as to suffer a cholesterol problem that would have killed him or left him a mindless vegetable on life-support if he hadn't become a Superior.
Akimichi Chouji from Naruto, due to his clan's fighting stylenote Using their most powerful technique turns them thin, but they have to eat a lot to bulk up and use it again. (and possibly genetics, his dad Chouza is similarly built). Also, being called fat triggers his Berserk Button:
Kurita from Eyeshield 21. The man ate 100 cream puffs on one occassion. In an Omake, Kurita ate 4 bowls of rice that are stacked to tower way above the bowl itself with enough food there to feed a large family. That's his breakfast.
Chang aka Cyborg 006 from Cyborg 009.He's a restaurateur with his own business on top of that, and that he also worked in the food industry before being turned into a Cyborg. Furthermore, his Cyborg ability (fire breathing) helps in his line of work.
In The Prince of Tennis there's Kei Tanishi from the Higa team. Big, mean, with the physique of a Sumo wrestler, and able to put away HUGE amounts of food. Seeing him eat yakiniku made Fuji lose his appetite, and that's saying much.
Chihiro's parents in Spirited Away definitely count as this. They see a buffet, sit down and start stuffing their faces. When Chihiro returns a few minutes later they've eaten everything on the table and are about four times as big. And they've transformed into pigs. To be fair, it was magical food.
Beyblade: Metal Fusion has the main character Gingka. When the World Beyblade Battling Association would grant any one wish to a winner of a Survival Battle Competition, this happens...
Madoka: "You're not going to wish for a 10 layer cheeseburger, are you?"
Then there's Benkei, who is commonly seen with a mountain of burgers next to him.
Kirio Hikifune from Bleach. Very justified as she has to bulk up to recharge her reiatsu. Not to mention she's also an Iron Chef and her Gate is nicknamed "Palace of Food", since she uses her reiatsu to cook herPower Up Foods. And it's subverted later; if Hikifune uses up all of her reiatsu... she temporarily slims down and goes from a Big Fun lady to a total babe who resembles Matsumoto, of all people.