"I'd like 20 tacos of grilled meat, some pozole with pork legs... oh, and a large diet soda, 'cause I want to lose weight!"When a character (usually a Big Eater, scarfing junk food at an alarming rate), pauses to make one tiny concession to health. Bonus points if they act like this counterbalances the calories they've just consumed. This is a standard comedic effect used in various media to emphasize the overindulgence that came before. In various talk shows that featured exceptionally obese people, they would often show a fast food customer ordering an exceptionally large meal including multiple sandwiches, fries and desserts, and concluding with, "and a Diet Coke." Despite being a staple joke on obesity and hypocrisy (especially the trusted "Americans are fatasses" routine), it happens in Real Life for various legitimate reasons. Diabetics may not be concerned about their intake of savories but must watch their sugars. Some people just prefer the taste of diet sodas (Diet Coke, for instance, is based upon the failed New Coke's formula, rather than Classic Coke.) Finally, even from the much-mocked calorie intake standpoint it actually does make sense— a thousand calorie gut bomb with a diet soda may be silly on its face, but it's still relatively better than a twelve-hundred calorie meal with a regular soft drink! (Soda averages 150 to 200 calories; a heavy soda drinker can see a tremendous benefit from cutting those calories, as soft drinks are the biggest source of sucrose and fructose in fast food.) Related to Hypocritical Humor, and also overlaps with Arson, Murder, and Jaywalking. A specific example of the Perfect Solution Fallacy.
— "La Dieta", Mexican group La Fresa
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- A Channel 4 "Friends is sponsored by Nescafe" clip had two women drinking coffee. The one with the huge cream cake in front of her was offered the sugar and reacted with horror, taking sweeteners out of her handbag.
- There was a Diet Coke commercial from the '80s featuring a Sumo wrestler being told by his master that he needs to greatly increase his calorie intake, then after Sensei exits, the wrestler looks around, and pulls out and taps a can of Diet Coke while the theme "Just for the taste of it" starts playing.
- Back when William "The Refrigerator" Perry was a big name in American football, McDonald's did a commercial starring him. The young woman taking his order (whose height, by the way, only went up to about the middle of his chest; The Fridge was a big guy) read it back to him: "That's four McDLTs, two large fries...and a diet Coke?"
- A promo for Kids' WB!'s Big Cartoonie Show has Clark Kent and Lois Lane parody this.
Lois: Clark, leave some for the rest of us!Clark: And a Bugs Bunny, please.Lois: Pig.
- An Armed Forces Network public service announcement had Elvis pulling into a drive through ordering a rather large order of stereotypically southern greasy food, and finishes it with "and a diet cola. Trying to watch my weight."
- A commercial for Chili's restaurants in the 80's has three friends talking about how hard it is to be fit and lose weight. One of them says that all that is needed is discipline. Their waitress comes to their table with their orders: a chicken salad without dressing for Friend #1, a burger without bun for Friend #2, and a hot fudge sundae without walnuts for Friend #3.
Friend #2 (incredulously): No walnuts?Friend #3: Discipline!
Anime and Manga
- Marvel Comics once did a gag issue of its What If? title, featuring short gags of a single page or less. One gag was "What If Tony Stark had an eating problem instead of a drinking problem?" The first panel shows an overweight Stark telling his date he can stop eating anytime he wants to, then he gives the waiter his order: "I'll have a cow, medium rare. And a Tab."
- At the end of Astérix and the Big Fight, Obelix decides that he needs to lose weight, and so he'll only have a lightly garnished cracker at the end-of-story-banquet. When Asterix asks what the cracker will be garnished with, Obelix declares "A roasted boar!"
- In a Looney Tunes comic book story featuring Bugs Bunny and the Tasmanian Devil, after Taz goes on a massive eating binge that started with an eating contest that he won, Bugs Bunny after using the cash prize to pay for damages and amount of extra food Taz has eaten buys an after-dinner mint for Taz with what little change he had left over. Taz refuses the mint, saying that he has to watch his figure.
- One early Rocky strip strip uses this joke, with a horrified Rocky and Tommy witnessing a rather large man with greasy hair ordering a hot dog wrap from a street food vendor, but with cheeseburgers as well as hot dogs, mashed potatoes, fried onions and french fries with the oil still on them... and a Pepsi Light. The vendor describes the following scene as watching a komodo dragon devour a pig.
- In Superman II, Lois is using a citrus juicer to squeeze a fresh glass of orange juice "because it's good for you"... while she's smoking.
- In Harold & Kumar Go to White Castle, when Harold and Kumar finally get to White Castle, the former requests 30 sliders, 5 french fries, and 4 large cherry cokes. Kumar orders "I want the same, except make mine Diet Cokes."
- The Santa Clause gives us this little tidbit: "And I'll have a Caesar. No dressing. And one of those homemade cookies, the warm chocolate chip. No nuts. And a little slice of cheesecake. Uh, creme brulée, and, um, hot fudge sundae, extra hot fudge... On the side."
- Done in A Cinderella Story.
- Also done in True Romance when Christian Slater's character goes to buy "the two biggest, fattest burgers" a burger stand has, two chili fries… and a Diet Coke. This is done in contrast to his wife getting beaten savagely — nay destroyed — by a very angry James Gandolfini.
- In The Nutty Professor 2, Sherman's mother mentions her latest diet: You can eat as much as you want, as long as you also drink lots of grapefruit juice to help digest it. Presumably she thought the citric acid would destroy the food completely. This diet exists outside the movie. No shit.
- Precious played this while asking a bucket of fried chicken. She said she would choose the side later because she was trying to watch her figure, but when the lady was looking for the side, she runs away with the chicken without paying.
- Brazilian movie A Partilha (based on a play) has a woman writing a "diet control" list. One of her three sisters gets it, and the four read and laugh seeing all entries have Diet Coke. One even mocks it:
"A cheeseburguer, two coconut cookies, breathing complications, a heart attack and a Diet Coke!"
- Making Mr. Right contains a running joke in which Ann Magnuson’s character always drowns her sorrows in Diet Coke and a pint of Fruzen Gladje ice cream.
- Alcohol-related example in So's Your Old Man. After filling a whole glass—not a cocktail glass or anything, but a whole dinner glass—almost to the rim with liquor, Sam dilutes it with a single drop of water.
- Inverted: A fat woman visits her doctor. He tells her to stick to a special assortment of fruit and vegetables for the next whole week as part of her new diet. After a week, he weighs her and says "Jesus Christ, you grown even fatter! What on earth did you do?" "Well, doctor, you see, after all those tasty little goodies I just found too very hard to choke down that diet of yours as well."
- The old joke about a man who orders a banana split, with ice-cream, fudge, chocolate sauce, crushed nuts and whipped cream. The waiter asks if he'd like a cherry on top. "No thanks, I'm on a diet".
- A small town doctor put a fat woman on a diet. The following day, he called the local lunch counter where she ate every day, asking the owner to check and see if she's following the diet. The owner looks out at the dining room. "Yes. She's just finished her diet meal. Now she's having her regular lunch."
- In his book Couplehood Paul Reiser jokes about this phenomenon using the related "diet" foodstuffs of cottage cheese and half a peach. Supposedly having either of these makes any meal a dieter's platter.
- In Dave Barry Does Japan, Barry reports seeing a sumo wrestler, after a match, drink a soda. The wrestler burped, so powerfully that it produced a "surfable wave" across his belly. Then Dave notes that the soda in question was a Diet Coke.
- In Bridge of Birds, there's a morbidly obese merchant who orders an obscene meal, but then passes on dessert because he says he needs to watch his diet.
Ten Ox: Master Li, you won't believe this, but that merchant began with four large tureens of pimento and dumpling soup. Then he devoured three bowls of mussel stew, a pound of pickled mallows, two pounds of steamed snails, three servings of soft-shelled crabs, two plates of sweetmeats, ten honey cakes, and a watermelon. The proprietor wondered whether the esteemed guest might care for six or seven quarts of peaches in heavy syrup, but the merchant explained that he was on a diet and would be forced to settle for a gallon of green tea flavored with pine kernels.
- In Chapter 3 of the Dean Koontz novel Cold Fire, reporter Holly Thorne goes to a bakery for lunch, orders five different pastries, then asks for a Diet Coke.
- Subverted in one of the Sweet Valley High thrillers; Jessica is waitressing when an obese guy is rude to her while placing an order. She pointedly gives his thin wife the milkshake he ordered and gives him a Diet Coke instead.
- The Bands Of Mourning has a variation: Wax, in order to use his powers, needs to drink steel flakes in a non-aqueous solution in order to be effective in combat. He prefers whiskey. His wife, Steris, prefers cod liver oil.
Steris: A wife needs to look after her husband's health.
Live Action TV
- On an episode of The Odd Couple, Oscar asks a visiting monk to make him a hamburger. On the burger, he asks for mustard, relish, pickles, hot sauce, peppers and chili. The monk says, "No onions?" Oscar replies, "No, I've got an ulcer."
- Stargate SG-1: In Upgrades, the team's metabolisms are vastly accelerated due to alien armbands they're wearing, so they break out of the Mountain in search of protein. Jack orders three steaks and a baked potato, Daniel orders the same but with four steaks, and Sam orders the same again (so, four steaks with baked potato) but additionally with french fries. Oh, and a diet soda. Seeing the looks Jack, Daniel and the waitress are giving her, she protests "I like the taste better!"
- In an episode of Three's Company, Jack is working as a short-order cook. A female customer asks if the restaurant offers a diet platter; upon being told yes, she says, "I'll take two."
- Friends: In TOW All the Kissing, Joey walks in on Chandler having a very girly bath (he doesn't know Monica's hiding under the water so that Joey won't see her), he asks Chandler if he wants anything from the take-away. Chandler orders for Monica but finishes the order with "and a Coke" then squeals in pain as Monica secretly objects to that last and swiftly corrects that to "And a Diet Coke". Monica tends to worry about her weight a bit because she used to be fat, but, considering the amount of take-away Chinese and pizzas she eats, the Diet Coke isn't much of a calorie saving.
- In the Wings episode "Wingless, Part 2", the Hacketts are flying a country music duo on a concert tour. When the overweight member of the pair asks for a Diet Coke, her oversexed partner sarcastically compares it to rearranging deck chairs on the Titanic.
- Also occurs in the British TV series Porridge, where Fletcher is offered cocoa, which he accepts, and then sugar. He refuses the biscuits, citing watching his weight, as he dumps at least four heaping spoonfuls of sugar in his already-sweet cocoa.
- In an episode of 30 Rock an incredulous donut-shop salesgirl checks that Liz wants "a dozen donuts to stay?" to which Liz adds, "And a skim milk!"
- A sketch on The Ossie Ostrich Video Show had Ossie asking for 25 sugars in his cup of tea before adding "...but don't stir it. I hate anything sweet."
- Frasier. When taking part in a weight-loss challenge yet finding that he's still gaining weight, the titular doctor exclaims, "But I added a salad to every meal!"
- Nickelodeon's My Brother and Me had a variant. Roger once made a comically large submarine sandwich for lunch that he prepared to eat all by himself and wash down with root beer. Then, after judging the sandwich's weight, Roger decides to settle on diet root beer, instead.
- The Sooty Show: When Sooty asks for sausage, egg, baked beans, chips and fried bread with jam for breakfast, Soo says that she doesn't want all that as she's on a diet - so no jam on her fried bread, thanks.
- Defended by Donna on Suits;
Mike: I don't get that. You get a skimmed milk latte, and then you put whipped cream and sugar in it.Donna: Because I get skimmed milk, I can put milk and sugar in it.
- Happens in The Dukes of Hazzard, in the episode "Ghost of General Lee":
Enos: A double order of catfish, hush puppies, pickles and onions, large order of fries, and extra thick chocolate milk and two slices of pecan pie. Is that right?Roscoe: Yeah, and get something for yourself Enos.Enos: You want that pie a la mode?Roscoe No Enos, I don't want it a la mode. I gotta watch my calories!
- El Chavo del ocho: At Doña Florinda's fonda (restaurant), she was surprised at her landlord's order because she thought he was on a diet. His response for her comment was asking for one of the chickens to come earless.
- The above mentioned joke shows up in The Lucy Show, where Vivian orders a huge hot fudge sundae with chocolate syrup, whipped cream, and lots of nuts, but declines the cherry on top. "No, thank you, honey. I'm on a diet."
- In one episode of The Sopranos, the heavily overweight Vito Spantafore orders a Grande Nacho and a Diet Coke.
- On an episode of the Mad TV sketch Reality Check that had Michael Jackson as its "celebrity guest," co-host Belma Buttons does this.
Belma: All that pancake makeup he's wearing got me thinking about IHOP again! Girl, what I wouldn't do for a Rooty Tooty Fresh 'n Fruity with a side of biscuits, 14 hash browns, a bacon and cheese omelet with grilled peppers and onions, a T-bone steak cooked well done...oh, uh, and a Diet Coke!"
- In one episode of Cheers, Norm and Woody have dinner at a local restaurant called the Hungry Heifer, where Norm is a regular:
Norm: (to waitress) I'll have the Feeding Frenzy Special, for two.Waitress: (turns to Woody) And you, sir?Woody: Umm, wasn't he ordering for both of us?Waitress: No...Woody: Oh. Okay, I'll have the same, but give me just one.
- "La Dieta" by Mexican group Banda Fresa is about a Camp Gay character asking for all sorts of Mexican food and ending always with a large diet soda.
- Tenacious D had a sketch on their title album that featured this joke. Jack is trying to watch his figure, so he goes to a drive-thru and orders a Junior Western Bacon Chee, a small (SMALL!) Seasoned Curlys, a Filet-of-Fish sandwich ("which has less calories, 'cause it's fish,") four chicken nuggets (shouting "put two of them up your ass" when they say it comes in a pack of six), a mixture of half Coca-Cola and half Diet Coke, and a Cherries Jubilee, all at the same time.
- Mika's "Big Girl (You Are Beautiful)" has a refrain of "Diet Coke and a pizza, please!"
- Psychostick's Do You Want A Taco
- I'd like 4,000 tacos and a diet coke.
- In Matthew Good's song "21st Century Living," which comments on how our society wants to make everything bigger and better (i.e. supersizing it all), Matt wryly notes that we should just supersize everything. Voiceover says: "I'd like to supersize death. Can I have a supersize of death? I'd like to supersize a death with a Coke."
- This verse from Dread Zeppelin's cover of Bob Marley's "Stir It Up"
- A similar situation was depicted in a Beetle Bailey strip in which the already-corpulent Sergeant Snorkel piled one sinfully indulgent treat after another from the Camp Swampy cafeteria onto his tray, and when called out for it defended himself by saying that everything in the cafeteria was low-fat. This prompted Beetle to point out that the only high-fat thing in the cafeteria was Sarge himself!
- During an episode of NBA Open Court, a question was asked about what the panel used to eat before a basketball game. Notably, Charles Barkley said he used to have "a McDonald's fish fillet, a large fries, a milkshake, and a Diet Coke, and that's how I kept my girlish figure" before games early in his career. Mark Jackson, too.
- "Fluffy" comedian Gabriel Iglesias mentions that he drinks diet soda, "so [he] can eat regular cake".
- In Louie Anderson's stand-up special "Louie in St. Louie," he details his trip to the grocery store for "some tuna and some bread, some milk, chips and cookies and Diet Coke."
- Inverted by Dennis Miller in They Shoot HBO Specials, Don't They?, while talking about air travel:
"Boy, they apologize a lot on the flight now, don't they? These people say "we're sorry" more than Exxon's field rep in Alaska. Swear to God, if the plane ever does go down, that's the last thing you'll hear: 'This is your Captain speaking. You're about to bite it. Sorry 'bout that. Your last drink's on us, okay?' 'Yeah, stewardess, I'll have a, uh, Diet Coke...well, fuck it, gimme a Coke.'"
- In White Wolf's Game Studio's superhero game Aberrant a character being interviewed about the nova's increased metabolism mentions ordering fifty Whoppers and a small Diet Coke at Burger King.
- In the musical adaptation of Footloose, Wendy Jo says, "I'll have a hula burger double patty cheesemelt with extra mayo and an order of fries," The other girls just stare at her, and she sheepishly finishes "...and a Diet Coke."
- In the ten-minute duet script Black Market Arts, when both cops agree not to arrest each other in the end, they decide to go the art show together. They take an entire case of high-fat, high-cholesterol cookies, and the second cop offers to buy the first cop a large popcorn with butter and a hot dog. The first cop replies, "Oh, yeah, and uh, Diet Coke."
- In Sam & Max Hit the Road, one of the answering machine messages Sam and Max get is a wrong number for a bakery, with someone placing an order for "200 lemon meringue pies and a small diet soda".
- In Papa's Hot Doggeria Big Pauly's standard order is a kielbasa loaded with everything under the sun, a large box of Candy Jack and a large Diet Fizzo.
- In this Ponyville comic, Dash orders a large order at Burrito Burro's "...and a salad!"
- In this page of The Wotch, Sonja (who is actually Jason under a spell, and not overweight at all) orders a huge number of snacks on a mock-date (hey, "her" figure was magically created, and she's not the one paying!) Her clueless date jokingly asks if she also wants a Diet Coke. Sonja's response? "Are you calling me fat?!"
- A variant in Arthur, King of Time and Space, when Guenevere criticises Merlin for eating junk while exercising as missing the point. Merlin retorts that the point of exercising is to let him eat what he wants.
- In The Salvation War, Bill Clinton orders in a Macdonald’s "a double quarter-pounder with extra cheese, two super-size portions of fries, oh and a small diet soda please."
- Not Always Right
- One story is about a customer at a movie theater concession stand who asks for enough artificial butter in his popcorn to make it start swimming, and then says "Lemme have a Diet Coke. A small one. I’m trying to watch my weight."
- In another one, the customer orders a giant sundae but asks them to hold the cherry on the grounds that cherries are fattening.
- This customer makes deep-fried Oreos... and so, gets the sugar-free Oreos so they'll be healthier.
- Sister site Not Always Working had a case where the customer had a Diet Coke with their meal. The employee mocked the customer along the "health benefits" lines of this trope...which, in this case, was not only rude (and thus a bad move in and of itself) but wrong; the customer really did prefer the taste. It ended badly for the cashier (and, by extension, the restaurant) when the cashier persisted in being rude.
- During an Achievement Hunter Let's Play, Michael related how his girlfriend had, along with a large supply of snack cakes, purchased one apple. He noted that the apple did not undo what she had just done.
- In The Most Popular Girls in School, Deandra the New Girl makes the following request in the cafeteria: 'Lemme get some tater tots. Oh, and also a slice of pepperoni pizza, and also a basket of jalapeno poppers, and some chicken nuggets, a ketchup boat, three potato pancakes, a creamsicle, two quesadillas, a bread loaf, side of ranch, some pixie sticks, taco salad, order of ribs aaaaand a Diet Coke. No— strawberry shake. No! Diet Coke! NO! Both.'
- In Bonus Stage, Joel orders a Triple Quarter Pounder but holds the mustard because he's trying to watch [his] figure".
- In Pet Peeves by Matt Santoro, Matt says that he once saw a woman at McDonald's order a Big Mac, an extra-large fry, and a diet soda.
- In the Taco-Man Plays a Video Game review of Captain Novolin, Taco-Man claims to have learned that everyone should try to eat healthy, and avoid sugary snacks. Later, he visits a fast food restaurant, and orders a double cheeseburger, some cheese fries, a soda with cheese...and a glass of milk, after ceaseless recommendations from one of Captain Novolin's doctors.
- The Super Mario Logan episode, "First Day of School!" introduces the character of Atso (short for "Fatso"), an ugly and obese kid who is surrounded by Twinkies, a Hershey's candy bar, Zebra Cakes, and a Diet Pepsi.
- In an episode of Beavis and Butt-Head a rather large woman comes into Burger World and orders "a large chocolate shake, 3 orders of onion rings, an apple pie, and a diet cola".
- Cats Don't Dance has a subtle example where Darla Dimple is pigging out on a big pile of food. It's mostly junk food, but if you look closely there's a single apple on the pile.
- Dennis the Menace: Concerned over Mr. Wilson's health, his wife forces him to enter a gym. When Dennis' antics get him expelled from there, Mr. Wilson is grateful enough to give the kid a sundae. Mr. Wilson has one as well but, wanting to lose weight, gives Dennis his sundae's cherry.
- On DuckTales when Burger Beagle orders a (rather large) meal from Gizmo Duck (he's pretending to be the drive-thru robot speaker), he orders a diet cola as well.
- Family Guy:
- While driving Lois' pregnant sister to the hospital, Peter stops off at a drive-thru to order several cheeseburgers, but vacillates on the fries: "If I have fries, is anyone else gonna have any? I don't wanna be the only one eating 'em. I'll feel like a fatty."
- They later did a straight depiction of the "heavy woman drinking diet soda" gag, and they were even nice enough to explain the joke.
- The very first episode had a variation of this joke, where Peter, believing himself to be rich, decides to treat the family to the most expensive meal they've ever had. He takes them to a drive through and orders "six thousand chicken fa-ji-tas", to which Brian adds "and a 'so-sage' McBiscuit".
- A rather Black Humor version of this occurs in Futurama when the Omnicronians demand restitution for the humans eating their young.
Lrrr: Very well, you provide us with 198 billion humans. And an order of fries.Ndnd (nagging tone) Lrrr...Lrrr: All right! Cottage cheese!
- Hey Arnold!: When Harold gets teased for being overweight, he decides to get something else from the Jolly Olly Man instead of his regular 6 Mister Fudgies. The Jolly Olly Man says that diet Mister Fudgies have half the fat of regular ones. Harold orders 12 of them. Nothing about this scene (or the episode) is played for laughs.
- The Marvelous Misadventures of Flapjack: In "Who's That Man In The Mirror?", K'nuckles attempts to lose weight by forgoing exercise and drinking nothing but Diet Maple Syrup.
- In "The Duke of Detroit" episode of Motorcity
Chuck: Can I get the triple jalapeno burger with the fries and onion rings? Oh, and a side salad! Watching my weight, so-[realizes who he's talking to]"
- In Robot Chicken's Star Wars, two of the space slugs order out for Chinese food, including 5 million tons of Kung Pao chicken, 3 million pot stickers, 5 million tons of fried rice and... one order of scallion pancakes.
- In an episode of Rocko's Modern Life, Rocko and Heffer are behind a rotund pig woman at the movie concession stand, and she orders a substantial amount of snacks... "and a diet soda. After all, I've gotta watch my girlish figure."
- The Simpsons:
- The joke is taken a step further when, after Homer orders an assortment of fried foods from Krusty Burger and the clerk offers to deep-fry the bag. He accepts the offer, and then asks for "a Diet Coke. Deep-fried."
- While at an ice cream parlor, Homer is on his health-kick, so he orders a low-fat vanilla topped with a bunch of bland-named junk food and candy products.
- In an early episode Homer goes on a diet, so Marge introduces him to rice cakes. She tells him they're only 35 calories a piece, but he can add a little something for flavour. Homer piles the cake high with toppings and then says "mmm, only 35 calories!"
- When Homer first meets the wide pride advocates, they have a table with several fattening foods and cans of Diet Coke.
- Occurs in not one but two episodes of Sons of Butcher. In the first one, Ricky orders most of the greasy spoon diner's menu, deep fried (even the friend chicken!), but adds a diet coke to watch his weight. The other time, he orders a very processed cheese-heavy meal from a fast food restaurant with regular cokes. But when Doug points out the fat contents, Ricky agrees... and switches his cokes to diet.
- In Teen Titans, Cyborg does this at an entirely meat based restaurant. He orders multiple combo meals in rapid succession, then stops and asks for a diet soda. But when told they do not have soda (only meat), he simply asks for a cup of meat juice. Being part cyborg as well as in shape makes this lesser than most examples.
- In the 1987 Teenage Mutant Ninja Turtles series, Rocksteady asks the secretary, "Bring me five hundred jelly donuts and a diet soda. I'm trying to watch my weight."
- An episode of Tiny Toon Adventures has one when Plucky finds a bottle from a wave:
Hamton: Gee, Plucky, nice trick! Order me a hamburger, onion rings, and a double shake....(Buster and Babs give mean looks at Hamton)Hamton: ...and a diet cola.
- The Twisted Tales of Felix the Cat: Roscoe and Felix got a new TV set and Felix bought several snacks for the two of them to eat. Instead of stating how much each snack cost, the cashier shamed Felix by stating how many calories each snack had. When the cashier asked if there was anything else Felix wanted, he showed a diet soda.
- This happens frequently, not because people actually are thinking in losing weight with the diet soda, but for other reasons. One of them is that they prefer the flavor of the diet soda to the regular one. Another reason is conditioning from continuous drinking of this soda in the past. Even another is the influence of publicity. Finally, you always have peer pressure.
- Additionally, regarding the massive meals consumed, there are indications that diet sodas actually contain appetite stimulants, causing people to become hungrier and, consequently, to eat more food.
- Diet Cokes and Pepsis contain more caffeine than the standard fare, so if you, say, want caffeine for an asprin, but don't want to eat it on an empty stomach...
- You know that thing from The Salvation War above about Bill Clinton going to a McDonald's and ordering a huge, fattening meal with a small diet soda? Yeah, he actually used to do that. Notoriously, he even did so while on the way back to The White House on a jog.
- Donald Trump reportedly subsisted on fast food and Diet Coke while on the 2016 campaign trail.
- Diabetics will order fast food and then get a diet soda, since the carbs in the food are usually much lower on the glycemic index than the carbs in regular soda. This troper's husband is often served regular soda, either by mistake or because people think he's being silly to order diet soda with unhealthy food.