Fad Diets
0Loading crowd target
0Loading crowd target
6correct to beat the crowd
40 free Fad Diets trivia questions with answers — trivia quiz, new questions added Oct 2026.
Every generation gets its own diet craze. For two centuries people have been promised that one odd rule would melt the pounds away: eat a single food, cut out a whole food group, sip a special drink, or follow a doctor with a bestselling book. Most of these plans faded as fast as they arrived, and many left behind stories that are stranger than their results. This quiz covers the best-known fad diets and the people behind them. You will meet the Victorian pamphleteers and preachers who started it all, the physicians whose names ended up on book covers and supermarket shelves, and the celebrities who made a regime famous overnight. There are questions on single-food plans, on pills and products that were pulled from sale, and on popular claims that scientists have tested and rejected. It is written for anyone curious about nutrition myths, for health and home economics classes, and for quiz hosts who want a round that gets a table arguing. Every answer comes with a short explanation, so you finish knowing why a diet caught on and what became of it.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Which snack is named after a 19th-century Presbyterian minister who preached vegetarianism and temperance?
Graham cracker
The Graham cracker was inspired by Sylvester Graham, whose followers, the Grahamites, gave up meat and alcohol and championed bran bread.
Q 02Which talk show host wheeled a wagon of fat on stage in 1988 after losing 67 pounds on the Optifast diet?
Oprah Winfrey
Oprah Winfrey showed off size 10 jeans on that episode, but she quickly regained much of the weight once she returned to real food.
Q 03Which actor landed in hospital after copying the all-fruit diet of Steve Jobs to play him in a 2013 film?
Ashton Kutcher
Ashton Kutcher said his pancreas levels went haywire on the fruitarian regime he adopted for the film Jobs; the Apple co-founder had practiced it since college.
Q 04Which breakfast cereal was created to ease indigestion among patients at the Battle Creek Sanitarium?
Corn flakes
Corn flakes grew out of experiments by brothers John and Will Kellogg while John ran the sanitarium, and a former patient, C. W. Post, was soon selling rival products.
Q 05The paleo diet, popularized by Loren Cordain's books, claims to copy what humans ate in which period?
Stone Age
Stone Age eating got a 1975 book of its own from gastroenterologist Walter Voegtlin, who declared that humans ate only flesh until 10,000 years ago.
Q 06The ketogenic diet was first tried at the Mayo Clinic in the 1920s as a treatment for which condition?
Epilepsy
Epilepsy in children was the target, and the diet fell out of use once effective anticonvulsant drugs arrived, decades before slimmers rediscovered it.
Q 07Which cigarette brand was pitched to 1920s women as a way to stay thin, lighting up rather than snacking?
Lucky Strike
Lucky Strike sales climbed from 14 billion cigarettes in 1925 to 40 billion in 1930 as the campaign presented smoking as an avenue to thinness.
Q 08Which parasites did some fad dieters supposedly swallow on purpose, hoping the creatures would absorb food?
Tapeworms
Tapeworms were meant to mature in the intestines until the dieter reached a target, then be killed with an anti-parasitic pill, a scheme counted among diet hoaxes.
Q 09Which snack cakes headlined the convenience store diet on which professor Mark Haub lost 27 pounds in 2010?
Twinkies
Twinkies, Oreos or Doritos every three hours still brought Haub's body mass index back to normal, his lesson to students that calorie counts drive weight loss.
Q 10Which toy gives its name to the cycle of losing weight on a strict diet and then putting it all back on?
Yo-yo
Yo-yo dieting, known to researchers as weight cycling, often begins with a low-calorie plan too extreme to keep up.
Q 11Which citrus fruit anchored the 1930s Hollywood diet, on the claim that it holds a fat-burning enzyme?
Grapefruit
Grapefruit has no such power, biochemists say; the plan's menu of fruit, toast and eggs simply added up to about 500 calories a day.
Q 12Which vegetable is the base of the soup in a seven-day crash diet also sold as the Russian Peasant Diet?
Cabbage
Cabbage soup dieters are promised a 10-pound loss in a week, but nutritionists say most of what goes is water rather than fat, so it soon returns.
Q 13Which low-carb diet, launched by a New York cardiologist in 1972, once claimed one in eleven North American adults?
Atkins
Atkins, the cardiologist, died in 2003, and two years later the company selling his branded products filed for bankruptcy as demand for them fell.
Q 21Naturopath Peter D'Adamo is the best-known promoter of diets that match meals to which inherited trait?
Blood type
Blood type diets have no scientific backing: dietitians, physicians and scientists agree that groups O, A, B and AB do not each need a separate menu.
Q 22Which organs already filter out harmful substances, the job that juice cleanses and detox diets claim to do?
Liver and kidneys
Liver and kidneys remove harmful substances without any help, and the British Dietetic Association has called the detox idea nonsense and a marketing myth.
Q 23Which dairy product goes into Bulletproof coffee, which Dave Asprey devised after drinking tea in Tibet?
Butter
Q 14Which place-named diet did cardiologist Arthur Agatston devise for his patients before it became a bestseller?
South Beach
South Beach was a rebrand: the plan was first called the Modified Carbohydrate Diet, then renamed after the Miami Beach district near Agatston's practice.
Q 15A lifelong gluten-free diet, adopted by many as a fad, is the only treatment for which autoimmune condition?
Celiac disease
Celiac disease is an abnormal immune reaction to gluten, a protein in wheat, barley and rye, that mainly harms the small intestine.
Q 16Which slimming company grew out of weekly meetings that Jean Nidetch hosted in her Queens apartment?
Weight Watchers
Weight Watchers began with six overweight friends in that apartment, and within two months 40 women were turning up each week.
Q 17Which singer set off a craze for the Master Cleanse lemonade fast by promoting it on television in 2006?
Beyoncé
Beyoncé's endorsement revived a regime first sold in the 1940s by Stanley Burroughs, which bans solid food and adds a saltwater flush every morning.
Q 18Fen-phen, a diet pill pairing that cost over $13 billion in damages, was withdrawn for harming which organ?
Heart
Heart valve problems surfaced in a 1997 Mayo Clinic paper on 24 fen-phen users, and regulators then received over a hundred further reports.
Q 19Which vegetable is the best-known negative-calorie food, said to take more energy to digest than it holds?
Celery
Celery uses only about 8% of its energy in digestion, far short of the 100% a truly negative-calorie food would need.
Q 20Which TV doctor was told at a 2014 Senate hearing that scientists were almost united against his diet claims?
Mehmet Oz
Mehmet Oz heard from Senator Claire McCaskill that products praised on his show were later cited in adverts, giving him a role in spreading scams.
Butter was Asprey's stand-in for the yak-butter tea he had tasted, and dietitians have dismissed the health claims for his wider regime as pseudoscientific.
Q 24What do followers of one dangerous fad diet dip in juice or smoothies and swallow whole to feel full?
Cotton balls
Cotton balls cannot be broken down by the body, so swallowing them risks choking and blockages in the intestines.
Q 25The macrobiotic diet, popularized by George Ohsawa in the 1930s, tries to balance which pair of forces?
Yin and yang
Yin and yang govern more than the plate in macrobiotics: the balancing extends to cookware, and its plans aim for a yin-to-yang ratio of five to one.
Q 26Which biblical prophet, who refused a Babylonian king's food, gives his name to a vegetables-and-water fast?
Daniel
Daniel and his companions asked for a ten-day trial on vegetables and water, the passage behind a partial fast kept by many Christians.
Q 27Which spice is stirred into the Master Cleanse drink alongside lemon juice and maple syrup?
Cayenne
Cayenne pepper spikes a drink that replaces every meal on the plan, which its creator relaunched in a 1976 book called The Master Cleanser.
Q 28Which fruit starred in a breakfast fad diet that swept Japan in 2008 and sold over 730,000 books that year?
Bananas
Bananas with room-temperature water made up breakfast on the plan, which an Osaka pharmacist devised for her husband before he spread it online.
Q 29Which dish is named after a Civil War physician who prescribed lean chopped beef and pints of hot water?
Salisbury steak
Salisbury steak honors James Salisbury, who blamed vegetables and starchy foods for producing poisons in the gut and wanted them cut to a third of the diet.
Q 30The hCG diet pairs fewer than 500 calories a day with a hormone that the human body produces during what?
Pregnancy
Pregnancy tests detect the same hormone, and US regulators have called over-the-counter hCG slimming products fraudulent and ineffective.