Monomania isn’t new. In fact, monomania actually began as a diagnostic term coined in the late 1700s to describe “a partial insanity, which left most of the intellect undamaged - mental disease affecting one aspect of the mind." It very much fits the person who decides to eat one food, ad nauseam, for an extended period in order to lose weight. It fits the concept of being “mentally preoccupied with one thing.”
Welcome to the monomania diet, also known as Banana Island Diet, or the monotrophic diet.
Leanne Ratcliffe (banana girl) became a YouTube sensation in 2014 as she chronicled a 40-pound weight loss by eating up to 51 bananas a day. The hashtag #monomeal became a popular trend soon after. It got a further boost when magician Penn Jillette lost close to 100 pounds eating only potatoes for several weeks. Actor Ashton Kutcher, on the other hand, ended up in the emergency room after following a “fruit only” diet to prepare for his portrayal of Steve Jobs.
This approach to dieting has been recycled repeatedly over several decades. The cabbage soup diet is probably the oldest version of the monomania diet. It was also called the TWA Stewardess Diet, the Model’s Diet, the Dolly Parton Diet, the Military Cabbage Diet, the Fat Burning Diet, and The Skinny. The Academy of Nutrition and Dietetics dates the first version to around 1950, but there may have been earlier versions. A recipe for Doughboy Cabbage Soup dates back to World War I. Soldiers at war had few vegetable options, and cabbage helps to protect against scurvy thanks to its high vitamin C levels. I suspect that the soldiers would have chosen to eat something else if they had the option. The cabbage soup diet became a go-to diet for models and stewardesses in the 1980s because they had to follow strict weight check-ins. Proponents of the cabbage soup diets all wanted quick weight loss.
When psychologists talk about monomania today, they are referring to patients who focus on one idea which consistently dominates their mind, thoughts, and behaviors. These patients won’t accept that their idea could be false or based on misconception of reality. Yet, these individuals can function normally in many other ways. Anorexia has been linked to monomania, for example.
A 2017 New York Post column featured a 49-year-old woman who wanted to lose weight before the holidays. She heard about a diet where she could eat her favorite fruit. The catch, she learned, was that she was only going to eat that fruit — breakfast, lunch, and dinner — as much as she wanted. She loved melon, so she ate it exclusively for 30 days. She lost seven pounds and then switched to other diets to help nudge another eight-pound weight loss. She was unable to sustain the melon diet beyond 30 days, and shared that she would never be able to look at melon again.
If you analyze a single food diet, the first thing you realize is that there’s no magic here. Eat one food all day long, especially a fruit or vegetable, and you will likely hit a pretty low daily calorie total; dramatic weight loss is not surprising. What’s also not surprising are the dangers associated with the diet, such as missing key daily nutrients. People can also consume such high levels of certain nutrients (potassium from bananas, for example) that it becomes unhealthy. In this sort of diet, you will likely shed muscle as well as fat. These diets can slow your metabolism, even temporarily, as your body struggles to manage the famine it perceives. You may experience insulin imbalances (something that Ashton Kutcher apparently experienced), fatigue, and periods of dizziness from hypoglycemia. As soon as you abandon the diet, you will likely gain back some weight, all the weight, or more weight than you initially lost. You will also likely lack energy to exercise, which enhances muscle loss.
A better way to diet
As a health professional, I can tell you that this one-food diet idea worries me. Most individuals are resilient and will likely withstand a couple of weeks of eating like this. But it can put vulnerable individuals at risk. It can also put a healthy individual at risk during strenuous exercise, for example. If you are desperate to lose excess weight, then choose a balanced diet with a low but sustainable calorie count. Emphasize fruits and vegetables, which fill you up with water and fiber. Choose portions of whole grains; select proteins like fish, beans, and tofu; and eat a serving or two of yogurt daily. Greek, non-fat yogurt is a good choice. It’s important to include small amounts of healthy fats, which help you absorb certain nutrients and help to keep you full.
Very low calorie diets (VLCD) are often used in hospital and doctor-supervised settings to help individuals struggling with serious or morbid obesity lose weight. These diets are not meant for the average person trying to shed 5-15 pounds. You might try intermittent fasts to help nudge weight loss, or to maintain it. Always check with your healthcare professional before starting a diet. Oprah’s rule of trying not to eat after 6 or 7 p.m. can also create a mini-fast until the next morning’s breakfast. This can help eliminate nighttime snacking, which can add a couple to several hundred calories to your daily tally.