Weight Loss
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40 free Weight Loss trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Weight loss is one of the most talked-about subjects in health, and one of the most misunderstood. Behind the meal plans and the bathroom scales sits a long, odd history of fad diets, bold claims and real science about how the body stores and spends energy. This quiz covers all of it: what calories and hormones actually do, where famous diets came from, the people who built the big slimming brands, the exercise crazes that filled living rooms, and the film and television moments everyone remembers. It is written for weight loss groups, wellness classes and anyone who wants a fun, fact-checked round for a meeting or a challenge night. Every answer comes with a short explanation, so you can play it straight through or print it for the group.
30 of 40 questions with answers and explanations. Play the quiz
Q 01When body fat is burned off, most of its mass leaves the human body as which substance?
Carbon dioxide
Carbon dioxide carries off about 84 percent of lost fat, breathed out through the lungs. Physicist Ruben Meerman worked out that the remainder leaves as water.
Q 02The 10,000-steps-a-day target began as the name of a 1960s pedometer sold in which country?
Japan
Japan got the manpokei, or 'ten-thousand step-meter', from the clockmaker Yamasa. A Tokyo clinic chief had urged everyone to walk that far each day, and walking groups soon formed in all 47 prefectures.
Q 03The ketogenic diet was devised by doctors in the 1920s to treat which medical condition in children?
Epilepsy
Epilepsy in children was the target, and the Mayo Clinic's Russell Wilder coined the term ketogenic diet. It fell out of favour once effective anticonvulsant drugs arrived.
Q 04The GLP-1 diabetes drug exenatide is a synthetic copy of a compound found in the venom of which reptile?
Gila monster
The Gila monster gets by on a handful of large meals a year, which drew one researcher to its venom. Exendin-4, isolated from it in 1992, was turned into exenatide.
Q 05Which talk show host wheeled a wagon holding 67 pounds of fat on stage in 1988 to mark her weight loss?
Oprah Winfrey
Oprah Winfrey had dropped from 212 to 145 pounds on the Optifast diet and showed off a pair of size 10 jeans. She regained much of the weight after going back to real food.
Q 06Filming of which Tom Hanks movie paused for a year so he could lose weight and grow a shaggy beard?
Cast Away
Cast Away shut down so Hanks could shed the 50 pounds he had gained for the early scenes. Director Zemeckis used the break to shoot What Lies Beneath with the same crew.
Q 07Which US president, remembered as the heaviest, hired a British diet doctor and logged his weight daily?
William H. Taft
The diet ran by post, with letters crossing the Atlantic over the next ten years. William H. Taft had hired Dr Yorke-Davies, an English diet expert, in 1905.
Q 08Which toy names the dieting cycle of losing weight and regaining it, a term credited to Kelly Brownell?
Yo-yo
Yo-yo dieting often starts with a plan too extreme to keep up, so the lost weight bounces back. Brownell, a clinical psychologist, also coined the phrase 'toxic food environment'.
Q 09Which crunchy vegetable is most often said to have negative calories, burning more to digest than it supplies?
Celery
Celery actually costs only about 8 percent of its calories to digest, far short of the 100 percent the claim needs. There is no evidence that any food is calorically negative.
Q 10According to the traditional dieting rule of thumb, one pound of body fat stores roughly how many calories?
3,500
3,500 calories per pound led dieters to expect a pound a week from cutting 500 calories a day. In practice the same cut tends to bring half a pound to a pound.
Q 11Which Queens homemaker founded Weight Watchers after starting a weekly support group for six friends?
Jean Nidetch
Jean Nidetch began the group in her apartment because a city clinic's meetings discouraged discussion. Within two months, 40 women were turning up each week.
Q 12Which hormone, made mainly in the stomach, peaks before meals and is nicknamed the hunger hormone?
Ghrelin
Ghrelin levels drop back once a meal has been eaten. Besides driving appetite, it plays a part in the sleep-wake cycle, taste and memory.
Q 13Which part of the human diet supplies about seven calories per gram, second only to fat's nine?
Alcohol
Alcohol packs 29 kilojoules, or 7 calories, into every gram, while sugar and starch supply only about 4. A drink's calories can come more from its strength than its sweetness.
Q 21Which hormone, released by the body's fat cells, tells the brain how much energy is held in reserve?
Leptin
Leptin was discovered by Jeffrey Friedman in 1994 after decades of research on obese mice. High levels tell the brain that reserves are full, and low levels that they are running down.
Q 22Ozempic and Wegovy are brand names for which drug, first approved in the US in 2017 for diabetes?
Semaglutide
Semaglutide is made by its originator Novo Nordisk, which sells it as Wegovy for weight management. A third brand name, Rybelsus, is also used for diabetes.
Q 23Which type of body fat, abundant in newborn babies, burns energy to make heat instead of storing it?
Brown fat
Q 14Which New York cardiologist's 1972 Diet Revolution promised a high-calorie way to stay thin forever?
Robert Atkins
Robert Atkins developed the plan at the private practice he opened on Manhattan's Upper East Side in 1959. It keeps carbohydrates tightly controlled and leans on fat for calories.
Q 15Which NBC reality show, launched in 2004, gave a cash prize for shedding the highest percentage of body weight?
The Biggest Loser
The Biggest Loser ran for 17 seasons on NBC up to 2016. An NIH follow-up of one season's contestants six years on found most had regained weight and their metabolisms were still slowed.
Q 16Which citrus fruit is the centrepiece of the Hollywood diet, an American fad dating back to the 1930s?
Grapefruit
Grapefruit first starred in an 'eighteen-day diet' of 1929, alongside eggs, toast and oranges. One early critic remarked that 'casualties' were heavy around Hollywood.
Q 17Which vegetable is the basis of the seven-day soup diet that spread by fax machine in the 1980s?
Cabbage
Cabbage soup is eaten in heavy amounts for a week on the plan, whose origins are unknown. It spread as 'faxlore', passed from one office machine to the next.
Q 18Adolphe Quetelet, the astronomer and statistician who devised the body mass index, came from which country?
Belgium
Belgium's Quetelet worked it out between 1830 and 1850 to describe the 'average man', and never meant it for medical assessment. It was first known as the Quetelet Index.
Q 19Which actress made the 1982 Workout tape, the first non-theatrical home video to top the sales charts?
Jane Fonda
Jane Fonda went on to sell 17 million videos between 1982 and 1995. The routine was developed by Leni Cazden and refined at the Beverly Hills studio the two ran.
Q 20Which weight-loss support group, based in Milwaukee, began in 1948, fifteen years before Weight Watchers?
TOPS Club
TOPS Club takes its name from 'Take Off Pounds Sensibly' and runs as a non-profit with chapters worldwide. One study found three-year members kept off five to seven percent of their body weight.
Brown fat makes up about 5 percent of a newborn's body mass, lying along the upper spine and shoulders. Babies depend on it because they cannot yet shiver to keep warm.
Q 24Which nutrient costs the body the most energy to digest, using up 20 to 30 percent of its own calories?
Protein
Protein is hard for the body to process, whereas fat uses up 3 percent of its calories at most. Carbohydrates sit in between, at 5 to 15 percent.
Q 25Dietitians say one serving of meat or poultry should be about the size of which everyday object?
A deck of cards
A deck of cards is the usual yardstick, about the same as the palm of your hand. The same guide matches a serving of cheese to a pair of dice.
Q 26Underwater weighing, a classic body-fat test, applies the buoyancy principle of which ancient Greek thinker?
Archimedes
Archimedes showed that a submerged body is pushed up by a force equal to the weight of the fluid it displaces. Weighing someone in air and again underwater reveals how dense their body is.
Q 27Which Romantic poet kept his weight down with days of biscuits and soda water, then potatoes drenched in vinegar?
Lord Byron
Lord Byron's weight swung between 9.5 and 14 stone, and he began strict dieting when he went up to Cambridge. A friend said he gobbled the vinegary mess 'like a famished dog'.
Q 28Which actor lost 62 pounds to play a gaunt, sleepless factory worker in the 2004 thriller The Machinist?
Christian Bale
Christian Bale got down to 120 pounds for the part and wanted to reach 99. The filmmakers refused to let him go any lower because of the risk to his health.
Q 29Which dance workout began when Colombian instructor Beto Pérez forgot his usual music and used Latin tapes instead?
Zumba
Zumba was first called 'Rumbacize' by Pérez, who improvised with salsa and merengue cassettes in the city of Cali. He launched it as a brand in 2001 with fitness videos sold by infomercial.
Q 30William Banting, whose 1863 Letter on Corpulence made 'banting' a byword for dieting, worked in which trade?
Undertaker
Undertaker to the Royal Household, his family firm buried George III, George IV and the Duke of Wellington. In Swedish, 'banta' is still the main verb for being on a diet.