What Is the Mono Diet?

The mono diet (also known as the monotrophic diet) has become one of the most heavily searched diets on the internet. If you've heard of it, you've probably read the claims that it can lead to quick and simple weight loss. But the claims are not based on scientific evidence and there are sound reasons to avoid this risky program.

Although we are explaining what the mono diet is, we do not condone it and medical professionals agree that it is not safe.

Background

In 2016, magician Penn Jillette published a book called Presto! How I Made Over 100 Pounds Disappear and Other Magical Tales. In it, he reported he kick-started his weight loss by following a mono diet for two weeks. The idea was to interrupt his regular eating pattern and then restart with a healthier diet.

For 14 days, Jillette ate nothing but potatoes (about five a day). Later, he began eating fruits, vegetables, and some whole grains. Once the book came out, the mono (or monotrophic) diet made headlines, as other people looking to lose weight wondered if they should try this method too.

How It Works

When you follow a mono diet, you eat only one food for several days or even weeks. There are different variations of the mono diet. There is a banana mono diet, an egg mono diet, a potato mono diet, and even a chocolate mono diet. There are no official or formal rules for how to follow this diet; it's open to interpretation.

Modifications

Some people may decide to follow a mono diet by sticking with one group of foods, such as fruit, vegetables, or meats. Or they may do mono meals, eating a single food for each meal, but switching up what that single food is.

Pros and Cons

Pros

Simplicity

Most traditional weight loss programs require you to count calories, balance macronutrients, follow a food plan, and/or monitor portion sizes. With the mono diet, shopping and meal planning is (seemingly) simple because you only eat one food or a very limited number of foods

Weight Loss

As you might imagine, when you eat only one food, your caloric intake plummets. Even if you eat a portion of high-calorie food, like chocolate, you are likely to eat less of it and consume less energy throughout the day. You will probably experience quick water loss and decreased bloating as a result. And the loss of muscle mass may make you feel thinner, as well.

But these weight loss results are likely to be short-lived. Even though fans of the diet say the program helps to curb cravings, anyone who has tried to avoid eating certain foods knows you generally desire the foods you can't have. And there are other serious drawbacks as well.

Cons

Dangerously Restrictive

There are significant health consequences when you don't eat a variety of foods to provide your body with important nutrients.

Nutrition researchers have known for years that cutting way back on calories can lead to compensatory behaviors, such as binge eating.

While there have been recent studies showing that severe caloric restriction can curb binge eating, those studies were conducted on obese individuals in medically supervised programs where dieters were getting supplements to make sure that their nutritional needs were met.

This type of diet is lacking in macro and micronutrients, such as protein, fiber, fat, vitamins, and minerals, which are critical for maintaining a healthy body. People who are only eating one food are not only cutting way back on calories but all kinds of nutrients.

Doesn't Promote Healthy Habits

To lose weight and keep it off, you need to determine what foods are best for you and how to manage portions. You need to exercise, get enough sleep, and manage stress. And you need support, whether it's from peers or professionals. A mono diet doesn't help with any of these.

Unsustainable

Managing hunger is not easy. In fact, it can make your life more difficult. Both animal studies and human studies have shown that severely restricting your caloric intake increases stress. And in one study, researchers found that young women, in particular, are likely to experience dissatisfaction with their bodies as a result of severe dieting.

Plus, your energy level will take a nosedive without proper nutrition. When you combine low energy, stress, and body dissatisfaction, going on a mono diet no longer seems simple or easy.

However, there are ways to promote a simple approach to weight loss by focusing on one food or food group. Try one of these healthier "mono" approaches:

• The mono-elimination diet. Choose one unhealthy food that you eat frequently and eliminate it from your diet. For example, if you usually eat ice cream after dinner, skip the treat for a week and see how you feel. Cutting out a bowl of ice cream can cut 300 to 500 calories per day, leading to a healthy weight loss of one-half to one pound per week.
• The mono-meal diet. Eliminate sauces, dressings, and other high-calorie, high-fat accompaniments from your plate so that each part of your meal is one simple food. So, instead of eating chicken with barbecue sauce, a baked potato with butter, and broccoli topped with cheese, you simply eat grilled chicken, a plain baked potato and steamed broccoli. This could retrain your taste buds to enjoy natural food flavors with fewer calories.
• The mono-hydration diet. Cut out sugary drinks, alcohol, and high-calorie coffee beverages. Simply drink water for thirst. While your body needs a variety of foods for good health, it does not need a variety of beverages. If you usually drink sodas, sweet tea, juice, and alcoholic beverages, you can cut 500 to 1000 calories per day with this method.
• The mono-swap diet. Choose one unhealthy food and replace it with a healthier version. If you eat chips with your sandwich at lunchtime, grab carrot sticks instead. Do you start your day with a danish or bagel? Choose a single serving of whole-grain cereal instead. If you like to spread butter on your toast, choose avocado, a healthier fat. By choosing foods that are high in nutrition, you may find that your body craves less junk food and feels fuller and satisfied for a longer period of time.

How It Compares 

Some other diets overlap with the monotrophic diet's main ideas. But this unconventional eating plan does not meet expert guidelines for healthy nutrition.

USDA Recommendations

Food Groups

The USDA guidelines suggest eating a balanced mix of fruits, vegetables, grains, protein, and dairy products each day. Clearly, the mono diet falls well short of these standards (even if you were to eat three different mono meals a day, you would only get three different kinds of food for that day).

Calories

The USDA suggests a daily intake of approximately 2000 calories for weight maintenance, and 1600 for weight loss, but these numbers vary based on age, weight, sex, and activity level. It's nearly impossible to get a suitable number of calories from a single food.

For example, Jillette's potato diet meant he was probably consuming only about 750 calories a day, far fewer than a man of his height (6 feet, 6 inches) needs. Calculate your own calorie needs for weight loss with this tool.

Similar Diets

See how the mono diet compares to some other seemingly simple plans.

Mono Diet

• How it works: Eat only one food, or type of food (such as fruit) for every meal, every day.
• Safety: This diet is not safe. Your body needs calories, protein, carbohydrates, and fats in order to function.
• Simplicity: There's nothing to track, measure, calculate, or weigh. Just pick your one food and eat only that (and skip the butter, salt, sugar, etc.).
• Sustainability: Both physically and psychologically, it's not a good idea to even try to eat this way, let alone continue for any length of time.

Egg Diet

• How it works: There are many iterations of the egg diet, from a mono plan in which you only eat eggs, to versions that include low-carb vegetables and other lean proteins along with eggs, or a keto version that adds butter or cheese to the eggs.
• Safety: Eggs are a good source of protein, fat, and several vitamins and minerals. However, eggs also contain a considerable amount of cholesterol and saturated fat and excess consumption should be avoided by people who have high cholesterol. Eggs also won't provide the balanced nutrition on their own, so avoid an egg mono diet just as you would any other kind of mono diet.
• Simplicity: Like other mono diets, an egg diet (even one with added ingredients) strips down your choices and meal planning so that you have very few decisions to make. This makes it pretty simple to follow, at least in terms of logistics.
• Sustainability: Even with some added ingredients, an egg diet won't give you the carbohydrates and calories your body needs to function. This could trigger unpleasant side effects (such as nausea, constipation, and headaches) that make the diet difficult, and dangerous, to sustain.

Mushroom Diet

• How it works: On a mushroom diet, the only rule is to replace one meal a day with a mushroom-based meal. Use any kind of mushrooms, but limit fat used in cooking them.
• Safety: This diet is very safe and sensible (as long as the overall eating plan is balanced and nutritious).
• Simplicity: The mushroom diet (also called the M-Plan diet) doesn't require much change in meal planning or preparation, and there is no counting, measuring, or tracking required.
• Sustainability: This diet is a healthy choice and it would be reasonable to use it for the long-term, especially if you replace meat-based entrees with mushroom-based ones.

Very Low-Calorie Diet

• How it works: On a very low-calorie diet, you typically don't eat any food at all. Instead, you get all your calories and nutrients from special meal-replacement drinks.
• Safety: This type of diet is usually prescribed by doctors and must be medically supervised and tailored to ensure that people are receiving adequate amounts of protein, vitamins and minerals, electrolytes and healthy fats.
• Simplicity: While it's hard to live without regular meals, especially when much or all of your diet is liquid, this diet works when prescribed because everything is pre-calculated and planned. Users don't have to worry about calorie counts, food choices, or portion sizes.
• Sustainability: This diet is usually only meant to be followed for a short time, and then transitioned to a weight-loss or weight-maintenance plan made up of solid foods. Following a very low-calorie diet and then resuming normal calorie intake can lead to weight re-gain, sometimes resulting in the person weighing more than their starting weight. In efforts to prevent this, it is important to have ongoing clinical attention and weight maintenance-specific counseling to support sustainable healthful behaviors and positive weight regulation.

A Word From Verywell

Due to the restrictiveness and inadequate nutrient intake, the mono diet is not recommended. While it may seem like a quick and simple approach to weight loss, denying your body of both macro and micronutrients is dangerous and can lead to a variety of problems.

Setting up a healthy weight loss program does take time and effort, but it is a worthwhile investment. You're much more likely to feel better, look better, and enjoy a boost of body confidence if you eat a nutritious diet and exercise to lose weight.