Read on as Michael Mosley fact-checks fascinating fad diets from the past…


Ingesting a tapeworm

In the 19th century, reports emerged of people ingesting tapeworm eggs. The idea behind this less-than-appetising dieting method was that the hatched tapeworm would eat ingested food in the person’s intestine, preventing them from gaining weight.

Michael says: This is certainly an unusual approach to dieting, and one that I tested out a few years ago for the BBC Four series Infested!. In the name of science, I flew to Nairobi in Kenya and deliberately infested myself by swallowing three tapeworm cysts. I let them mature inside me for about six weeks before swallowing a pill camera so we could film them in situ.

Despite being host to three large tapeworm I lost no weight at all, although one of the experts who helped set up the experiment suggested that I may have unconsciously compensated for their presence by eating more. After the experiment, I took a pill to kill the tapeworm – nothing came out so I can only assume that once they’d died, my body treated them like food and digested them. An ironic end: parasites eaten by their host.



In the early 20th century, tired of suffering from indigestion and obesity, American food-faddist Horace Fletcher came up with a novel way of improving digestion and keeping his weight down. The initial philosophy behind the diet wasn’t all bad – to take your time when eating, be mindful of what you eat and to only eat when you’re hungry. However, the main principle of Fletcherism, as it became known, was to chew everything you ate at least 32 times or until it became liquified and flavourless.

Michael says: For understandable reasons, Fletcher became widely known as ‘The Great Masticator’ and was denounced as an utter quack. Critics described his diet as potentially responsible for “constipation of the most serious kind”. But was there anything to be said for his methods? I think there was, certainly the idea that you should only eat when you’re hungry and take your time over your meal.

About a metre along the small intestine is a group of cells that react to food by releasing a hormone called PYY. This is a hunger-suppressing hormone that tells you you’re full. It can take the food you eat up to an hour to get from your stomach to these cells, so if you eat fast you will eat more. Lots of chewing also speeds up the breakdown of food in the stomach, meaning it gets to the PYY receptors faster.

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Lord’s Byron’s invigorating vinegar

Lord Byron
Lord Byron, an English Romantic poet (Photo by Getty)

Mad, bad and dangerous to emulate – the Romantic poet with the scandalous private life had an unusual method of keeping fit and healthy. He advocated drinking vinegar daily, as well as soaking food in the acidic substance as a way of staying trim. Admirers began copying this trend to get his famously pale complexion and slim figure.

Michael says: When it comes to the benefits of drinking vinegar, Byron wasn’t completely mad. We did an experiment on Trust Me I’m a Doctor, where we asked volunteers to eat a couple of bagels, then the following day eat another couple of bagels after drinking a diluted shot of apple cider vinegar. We measured what happened to their blood sugar levels and it turned out that the vinegar had a big impact, reducing the rise in blood sugar levels by 36 per cent. This is probably because the acetic acid in the vinegar suppresses the breakdown of starches, which means that if you consume it before a carbohydrate-rich meal, less sugar will be absorbed. Vinegar is acidic so should only be drunk diluted in small amounts or used sparingly in food.



Launched in the 1970s, Prolinn was a less-than-400-calorie drink that claimed to help you lose weight. For a while it was hugely popular, with more than two million people trying the diet, but did it work?

Michael says: Osteopath Robert Linn launched the notorious Last Chance Diet in the 1970s. Along with his book, you could also buy his miraculous “liquid protein diet”, Prolinn. An array of celebrities endorsed the product, claiming that dieters could lose up to 10lb (4.5kg) a week.

After initial success, however, the Last Chance Diet began to live up to its name when reports of related deaths prompted the FDA to investigate. Although some of the fatalities seem to have been people with already advanced heart disease, there was evidence in a few cases that the diet itself may have caused damage to the heart through “protein-calorie malnutrition”. The low-quality protein in Prolinn came largely from collagen, obtained from the tendons, ligaments and skin of animals, enhanced with artificial flavourings.



We are now only too aware of the multiple health issues connected with smoking, but back in the 1920s, cigarette companies were doing their utmost to promote their products any way they could. One of their tactics was to market cigarettes as a weight-loss aid.

The suggestion was that cigarettes could suppress your appetite and lead you away from edible temptations. US cigarette brand Lucky Strike ran advertising campaigns encouraging people to reach for one of their cigarettes rather than sweets – they were the most profitable cigarette brand for two years running.

Michael says: Cigarettes are extremely bad for you and cause the premature death of one in three of people who engage in the habit. That said, cigarettes do suppress appetite and people, on average, put on 5kg (11lbs) in the year after they stop smoking. But smoking’s proven dangers to health definitely outweigh any possible impact on weight loss they may have.



Warning label from a pharmacy bottle of arsenic
Warning label from a pharmacy bottle of arsenic from the early 20th century (Photo by Getty)

Before we knew of its dangers as a poison, arsenic was used in a variety of ways, including as a cosmetic and a weight-loss aid. Victorian diet pills often contained a mixture of dubious ingredients, including arsenic, with people completely unaware of what they were taking.

Michael says: Arsenic does have its medical uses, particularly in the treatment of cancer. In 2018, the US Food and Drug Administration (FDA) approved the use of an arsenic compound for the treatment of patients with acute promyelocytic leukaemia. But as a weight loss tool? Well, arsenic, in low doses, is a stimulant. So, in theory, a nip of arsenic could pep you up, so you might become more active, in which case you might burn a few extra calories. But the line between stimulation and death is a fine one.


Rubber clothes

Fashion could be just as dangerous as food when it came to questionable health choices of the past. In the mid-19th century, American inventor Charles Goodyear created the vulcanisation process, which allowed for the commercial use of rubber. As this revolutionary material became mass produced, inventors tried to cash in on its success by innovating new ways it could be used – including garments for weight loss.

Michael says: One of the things they did with rubber was produce corsets and knickers made of the stuff – it was thought that the rubber would hold in fat while making you sweat, and therefore lose weight. Unfortunately, what the material actually did was cause the wearer’s skin to break down, leaving it vulnerable to sores and infections.


Fat-reducing soap

Advert for La-Mar reducing soap
La-Mar soap promised to 'wash away' fat.(Photo by Getty)

In the 1920s, a company claimed it had created a soap that could “wash away fat and years of age” from your body. The advert for La-Mar soap stated that it worked like “magic” and could be used on any part of the body – from double chins to “ungainly ankles”.

Other companies soon jumped on the bandwagon with their own fat-fighting soaps, including Dr Paul Bouchaud’s Flesh-Reducing Soap, which claimed to absorb fatty tissues from any part of the body, proving the “needless use of dangerous drugs, dieting, steam pack or exercises”.

Michael says: This is absolutely bonkers, obviously.


The single egg diet

It’s not just a modern idea to worry about one’s weight. Back in 1558, Venetian merchant Luigi Cornaro published the first of his discourses on living a long and healthy life, titled The Art of Living Long. Cornaro had previously lived a life of excess and was encouraged to turn this around after suffering exhaustion and ill health.

He restricted his diet to 340g of food a day (bread, egg yolks, meat and soup), as well as a generous helping of half a bottle of wine per day. He later reduced his food intake even further to just one egg a day. There is debate over Cornaro’s age at his death, but it’s believed to be between the ripe old ages of 98-102.

Michael says: Long-term calorie restriction is the only thing that has been shown to extend healthy life in every animal species it’s been tested on. To get the benefits you see in rodents, you would need to cut down to around 1,500 calories a day. That said, they would need to be healthy calories packed full of nutrients. Unless Cornaro was enormously fat to begin with, I can’t see how anyone could survive for long on one egg a day.


The Sleeping Beauty diet

American singer and actor Elvis Presley eating a sandwich
With a diet ranging from deep-fried pickles to peanut butter to bacon and banana sandwiches, it's no wonder Elvis felt the need to sleep it off (Photo by Getty)

First referenced in the 1960s, the main principle of the Sleeping Beauty regime was that if you’re sleeping, you’re not eating. However, ardent followers of the mantra have historically deployed sleeping pills, alcohol and sedatives to ensure they stay asleep, sometimes for up to 20 hours a day. Elvis Presley was apparently a fan of the ‘diet’, having once put himself into a medically induced coma for a few days to avoid the temptation of eating.

Michael says: I can certainly see the logic to this one, but I can’t imagine any way you could keep people unconscious without causing them serious harm. Also, I imagine people would wake up ravenously hungry. Presley died hugely overweight, so he’s not a great advert for this method of weight loss.

Dr Michael Mosley (@DrMichaelMosley) is an award-winning writer and TV presenter. He presents BBC Two’s Trust Me, I’m A Doctor and has written five international bestsellers, most recently The Fast 800. He is also a columnist for BBC Science Focus magazine.

Additional words by Emma Slattery Williams, BBC History Revealed's Staff Writer


This content first appeared in the January 2020 issue of BBC History Revealed