Fad diets from history: Arsenic, cigarettes, and tapeworms

Recently, we published a feature covering the ancient history of fad diets. We learned that unusual and sometimes dangerous ways to lose weight are as old as the hills.

In this feature, we'll continue our wander through history’s darkened passages. We’ll investigate some of the more unusual weight loss fads from the 1800s to the 1950s. 

Once again, we’ll see that diet trends and dodgy weight loss techniques have a long and disappointing history. 

And we’ll learn that many fad diets from centuries past still haunt social media to this day. 

We’ll start off with perhaps the least ridiculous diet we’ll be covering today.

The first low-carb diet book

In the 1860s, a doctor suggested a diet to one of his patients — William Banting, one of London’s top funeral directors.

The diet involved reducing starches and sugars and eating three meals a day of fish or meat with vegetables and some fruit. He also suggested avoiding bread, beer, sweets, milk, and potatoes.

As fad diets go, this one doesn’t sound too left-field.

The diet was hugely successful for Banting, who lost a considerable amount of weight. 

So, wanting to share this miracle with the public, he explained his diet in a pamphlet called Letter on Corpulence.

At first, he distributed his pamphlet widely for free but eventually went on to sell tens of thousands of copies. 

Overall, the diet is fairly low-carb. However, it does allow for up to seven glasses of wine or sherry every day. So, it’s not exactly a keto diet.

‘The Great Masticator’

In 1898, American businessman Horace Fletcher lost almost 40 pounds (18 kilograms) by chewing each mouthful of food up to 100 times.

Fletcherism, as this technique became known, required you to chew your food until it became fluid.

Fletcher, an energetic man by all accounts, wrote a best-selling book on the topic and traveled the world, spreading the gospel of chewing.

He also taught people not to eat until they were “good and hungry” and never to eat when angry or worried.

However, followers could eat anything they wanted, as long as they chewed it until the “food swallowed itself.”

Apparently, those who followed the diet faithfully would only poop once every 2 weeks. And the poop was almost odorless.

According to historian and author Louise Foxcroft, “Fletcher carried a sample of his own feces around with him to illustrate this wonder."

This sounds a little extreme, because it is, but there’s some sense to it. 

For instance, ZOE’s scientists are currently running a study investigating whether the speed at which you eat is linked to health outcomes.

But slowing your eating doesn't mean you have to chew each mouthful 100 times. That’s a bit much.


Yes, arsenic weight loss pills. From the mid-18th century to the early 19th century, you could buy over-the-counter medicines containing arsenic.

Arsenic is incredibly poisonous, but at low doses, it acts as a stimulant. However, there’s a fine line between being slightly more energetic and dead.

And for some people who were very keen to lose weight, overdosing was a real risk.

Worryingly, not all products that contained arsenic mentioned this on their labels, which added an extra layer of danger.

Using arsenic for weight loss is a terrible idea, of course.

Interestingly, arsenic may induce weight loss, though it also causes serious damage to multiple organs. It’s not recommended.

A dose of worms

Now we’ve arrived at the early 20th century, and we’re talking parasites. Tapeworm capsules, to be precise. 

The premise is easy to understand: You take a capsule containing tapeworm eggs. Once these are inside you, the tapeworms hatch. Then they eat some of the food that you’ve eaten, which keeps you trim — allegedly.

According to peddlers of these pills, there were no side effects.

However, as the authors of a review explain: “This was a tremendous error, since the presence of this parasite [...] can cause abdominal pain and discomfort, cramps, colic, diarrhea, nausea, dizziness, vomiting, vertigo, headache, tiredness, malabsorption, anorexia, muscle pain, constipation, vitamin deficiency, anemia, intestinal obstruction, [jejunal perforation], appendicitis, and pancreatitis.”

Plus, some species of tapeworm can grow up to 82 feet (25 meters) in length.

And that’s really all you need to know if you’re still wondering whether this is a good idea.

We should note that because this fad began so long ago, we can’t be sure that the capsules really did contain tapeworm eggs. 

After all, diet quacks aren’t known for telling the truth, and identifying tapeworm eggs would be challenging. It could have been a scam from start to finish.

Worryingly, some people still sell these pills — illegally, of course — but who’s to know if they really contain tapeworm eggs? 

And although the theory of how they work seems “sensible,” there’s no evidence that taking these pills leads to weight loss.

There is plenty of evidence that a tapeworm infection is bad news.

Parasites: Keep or remove?

Recently, the wellness world has been running in the opposite direction: Parasite cleanses have become all the rage, with TikTok leading the charge.

Parasitic infections are a significant problem in many parts of the world. However, in the West, they’re not such a huge concern. 

Dr. Thomas Moore, an infectious disease expert and clinical professor at the University of Kansas School of Medicine-Wichita told Consumer Reports:

“If you really have a parasite, getting it diagnosed is the most important thing to do because there are effective treatments. [...] There’s little to no scientific data to support that these concoctions fight off infection.”

In short, wellness grifters are selling parasite cleanses that don’t work to people who don’t have parasites.

How acidic are you?

Dr. William Howard Hay, born in 1866, is most famous for designing the Hay diet. Nowadays, this is commonly known as the alkaline diet. 

The general idea is that you should avoid eating too many foods that become acidic after they’re digested.

If you do, Hay believed, this would cause your blood to become more acidic, leading to disease.

It’s true that your blood must be the right pH — if it’s too acidic or alkaline, it’s a serious problem.

But the foods you eat don't affect how acidic your blood is. 

As fad diets go, this one isn’t too bad — it’s not based in fact, but at least it’s not dangerous.

For instance, according to alkaline diet lore, most fruits and veggies are alkaline. And most ultraprocessed foods are acidic. 

So, if you’re upping your intake of plant foods while avoiding ultraprocessed foods, you’re likely to feel some benefits. But this has nothing to do with the pH of your body.

It’s not all positive, though: Whole grains and dairy are considered acidic, and cutting these from your diet means you’re missing out on some good sources of nutrients.

Incredibly, despite zero evidence to back up the alkaline diet’s claims, it lives on. 

On social media, you’ve probably seen people saying it will prevent cancer, obesity, and pretty much everything else.

Although it’s well over a century old, according to a review investigating the alkaline diet and cancer, “There is almost no actual research to either support or disprove these ideas.”

‘Reach for a Lucky instead of a sweet’

Nicotine suppresses appetite, so it’s perhaps no surprise that cigarette companies took a trip down the weight loss road.

In the 1920s, Lucky Strike wanted to get more women hooked on tobacco. So, they started their “Reach for a Lucky instead of a sweet” campaign. 

“When tempted to overindulge, reach for a Lucky instead,” their ads advised.

Amusingly, the candy industry was incensed by this attack on their products.

So, they began a revenge campaign, distributing information about the dangers of smoking.

Eventually, the Federal Trade Commission stepped in and stopped Lucky from promoting cigarettes as weight loss aids.

Sadly, Lucky’s marketing campaign worked very well, increasing their market share by more than 200%

We don’t need to explain why replacing food with cigarettes is a bad idea. 

Miraculous grapefruit

In the late 1920s and early 1930s, the 18-day diet rose to popularity. It involves eating an entire grapefruit with each meal. 

It’s essentially a low-carb diet, so along with the grapefruit, you eat eggs, meat, and other high-protein, high-fat foods.

In Hollywood, this eating plan took off. It became known as the grapefruit diet or Hollywood diet.

Meant to last “just” 18 days, the diet was very restrictive. It required people to eat only 600–700 calories a day, and it lacked nutrients. Even in 1935, this worried some experts. 

For instance, health educator Carl Malmberg expressed concern in his book Diet and Die.

He warned that many people who saw results from the diet continued it for well beyond 18 days. This, he writes, is “inviting certain catastrophe.”

The comeback(s)

In 1970, the grapefruit diet enjoyed a rebirth. According to one review, its return to center stage was thanks to the United States Department of Agriculture.

They promoted the diet because, in 1970, there was a surplus of grapefruit.

The grapefruit diet had yet another resurgence in the 1980s, rebranded as the 10-day, 10-pounds-off diet. Even today, you’ll see similar diets surfacing on the internet from time to time.

We should mention that a few small studies have investigated whether grapefruit (alongside a standard diet) might aid weight loss.

Some conclude that there might be benefits for certain populations, but others have found no significant reduction in weight. 

Eating more fruit is likely to benefit your health, but extreme calorie and nutrient restriction won't.

What to make of it all

If this journey through fad diets has taught us anything, it’s that people are willing to try anything to shed pounds.

At ZOE, we know that losing weight and maintaining a healthy weight are both incredibly challenging, so unusual and “simple” remedies often seem appealing.

Sadly, there will always be people looking to make a quick buck by hawking useless weight loss products. 

Our research has shown that everyone responds differently to food. So, finding the right way to eat for your body is key for helping you reach your long-term health goals

There’s no magic potion or approach, and you should stay skeptical whenever you’re promised quick results or miracle cures.


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