The main character of the movie “The Martian” is forced to eat only potatoes while trapped on Mars. That’s just science fiction, but here on Earth, this is the latest fad diet.

Nutritionists warn against trying the potato-only mono-diet, but some are tempted to try this extreme feat.

The Potato Diet: High Profile Weight Loss on Low-Calorie Dieting

Recent statistics make it clear that people are desperate to lose weight.

According to a 2017 study, the percentage of adults worldwide that had attempted weight loss in the previous 12 months was 41.5 percent.

Driven to shed pounds, people may become desperate enough to try extreme dieting. These extreme diets come in many forms, some of you may remember the cabbage soup diet or the grapefruit diet.

New diets continue to appear; currently hot is the idea of the mono-diet. Mono-dieting gets its name from the word “mono” meaning “one single thing” as in monogamy, monorail, or monocle. In this diet, the “mono” is a food item: one single food item repeatedly eaten for an extended period. Mono-diet books and YouTube channels promoting extremely restrictive diets continue to reach new audiences fascinated by the promise of quick weight loss and better health. The most common choice for this diet? The potato.

Potato mono-diets have enjoyed some publicity thanks to high profile eating stunts and celebrity involvement.

In 2010, a marketing effort by Chris Voigt, a member of the Washington State Potatoes Commission, involved eating only potatoes for two months. He did this to promote the nutritional value of the potato. Voigt’s blog from 2010 noted that “I don’t want people to think of this as a weight loss diet. It is not, and it’s not something I want people to replicate.”

Penn Jillette, a Las Vegas magician and celebrity, lost over 100 pounds using a potato mono-diet in 2016. He began the diet with two weeks of nothing but unseasoned, whole potatoes. During those two weeks, he lost one pound per day. He has maintained the weight loss since then but is no longer eating only potatoes.

In 2015, Andrew Taylor ate virtually nothing but potatoes for an entire year and lost around 115 pounds. He became famous on the internet as the “Spud Fit” guy.

But is a potato-only diet really the weight-loss miracle it claims to be?

Ruth Litchfield, an Iowa State professor of food science with a Ph.D. in nutritional science, works as a Nutrition Extension State Specialist and finds herself worried by dieting trends. When advising someone interested in a mono-diet, she asks them “Why do you think there are so many diets out there? Because none of them work long-term.”

“Whatever it takes to lose the weight is the same thing it takes to keep it off. It’s not like you diet for 12 weeks and you’re cured for the rest of your life,” Litchfield said.

So, before being convinced to eat countless sacks of potatoes, let’s recheck some health facts. There are two main concerns with a potato-only mono-diet: lack of nutrients and lack of calories.

What Happens to the Body Without Key Nutrients

The potato contains many essential nutrients, but not all of them. A nutrient is something that the body requires to maintain life. Without nutrients, certain functions in your body can’t happen. Lack of vitamin B12 may lead to difficulties in walking and memory loss. Lack of vitamin A leads to vision problems. The potato lacks these and other key nutrients.

In the very short-term, your body won’t notice a reduction of nutrients in your food. But in the long-term?

“You can survive on some really crazy stuff for a long period of time, but would it be your best body and best mind? No,” said Alison St. Germain, a registered dietitian and a licensed dietitian at Iowa State University. She works as a dietetic internship instructor and clinician.

In each of the weight-loss cases outlined above, the person on the potato-only diet eventually supplemented the diet with non-potato items which alleviated the nutrient problem.

Voigt consumed at least 20 non-potato items during his potato-only diet, including cocoa powder, olive oil, and hot sauces. Jillette added in things such as beans and salads after two weeks. “Spud Fit” Taylor added soy milk and took a vitamin supplement. It is important to note that: none of the potato-only diets of the individuals mentioned above contained only potatoes long-term.

Headlines proclaiming “Only Potatoes” do not provide the whole picture and often omit the fine print about nutrition.

How the Body Suffers Without Calories

When weight loss occurs because of the potato diet, it is because the body is taking in fewer calories than it is putting out. This is called a calorie deficit. When small calorie deficits are slowly introduced and maintained carefully, this can be an excellent way of improving health. For example, permanently reducing the amount of sugar added to your coffee is a minor change that you can maintain over time in order to reduce calories.

Small calorie deficits lead to weight loss and positive effects. According to The Centers for Disease Control and Prevention’s website (cdc.gov), calorie deficits that lead to weight loss of one or two pounds per week are safe. When done quickly during extreme mono-diets, however, such as when Jillette lost nearly one pound per day, there can be negative consequences.

In a perfect world, the body would make up any extreme calorie deficit by burning the fat that people want to lose. But this isn’t what happens. When your body doesn’t have the calories it needs to run all of the machinery in your body, things begin shutting down.

“Fasting or very restrictive dieting can induce stress responses,” Litchfield said, “Impaired mental and physical abilities are going to result from that.”

This stress causes several functions in the body to slow down in order to conserve energy, including immune responses. As a result, people who restrict their calorie intake may be more likely to get sick, although a causal link between these two things has only been shown in animals thus far. A study published in The Journal of Experimental Medicine in 2016 found that mice with a restricted calorie diet had extremely weakened immune systems.

Also of concern is the effect that caloric restriction has on metabolism. Metabolism is the process by which your body converts food into energy. When a person participates in an extreme diet, energy conversion slows down. Importantly, this change to the metabolism, called metabolic adaptation, doesn’t disappear once the diet is complete. A study publishedin the journal Obesity in 2016 found that metabolic adaptation still existed years after an extreme weight loss plan had been followed.

To prevent these negative effects and stress responses, caloric restriction must be small and introduced slowly. This slow introduction allows the body to acclimate to this new environment. A useful metaphor for this slow change in environment can be seen in scuba diving.

When a scuba diver is deep underwater, she cannot simply rise to the surface without risking injury to her body. If she tries to swim directly to the surface as quickly as possible, she is at risk of something called “the bends” that occurs when the body cannot adapt to the pressure change quickly enough. The bends can cause damage to the body, but a simple way to prevent this is by surfacing slowly.

When attempting weight loss, your body is in a similar situation. To get to safety while minimizing risk, you need to surface slowly.

How to Not Starve and Still Get Healthy

While the potato mono-diet may be appealing because it seems like a quick fix, the potential long-term health consequences make this diet of solo spuds a total dud. According to St. Germain, there are other ways to find a healthier you.

The focus that people place on losing weight when trying to become healthier is sometimes called the “weight-centered paradigm.” However, becoming healthier is not necessarily equal to losing weight. St. Germain recommends a “health-centered paradigm” in which small behavioral changes add up long-term to produce a healthier person.

Adding exercise, eating additional varieties of nutritious foods, and removing unhealthy behaviors such as smoking, contribute towards a healthier person regardless of weight.

For someone who is interested in resetting their relationship with food, such as “Spud Fit” Taylor was when he began his mono-diet, there are less dramatic options. A technique known as intuitive eating asks people to listen to the hunger signals from their bodies when deciding when to eat and when to stop eating. Keeping a food journal allows a person to remember how much they are consuming and allows adjustments.

Lastly, the final word should be given to those who have tried potato mono-diets.

Jillette said in a video where he promoted a book written about his weight loss that “If you take medical advice from a Las Vegas magician, you are an idiot who deserves to die. You have to do this for yourself and with your proper medical professionals.” Taylor was quoted in an article by Today saying that “This is not something I started to try to promote it to anyone else, it’s just an experiment I’ve done for myself.”

The advice of those who have tried this potato mono-diet? Do not try the potato mono-diet.

References

Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., … & Hall, K. D. (2016). Persistent metabolic adaptation six years after “The Biggest Loser” competition. Obesity, 24(8), 1612–1619.

Santos, I., Sniehotta, F. F., Marques, M. M., Carraça, E. V., & Teixeira, P. J. (2017). Prevalence of personal weight control attempts in adults: a systematic review and meta‐analysis. Obesity Reviews, 18(1), 32–50.

Tang, D., Tao, S., Chen, Z., Koliesnik, I. O., Calmes, P. G., Hoerr, V., … & Morita, Y. (2016). Dietary restriction improves repopulation but impairs lymphoid differentiation capacity of hematopoietic stem cells in early aging. Journal of Experimental Medicine, 213(4), 535–553.