FAQS About the Mono Diet

No, the mono diet isn't what you eat when you have "mono" also known as mononucleosis, the kissing disease, and Epstein-Barr. 

Although if you have mono, you might feel so poorly you only eat one food. And that is the mono diet.

What is the mono diet?
The mono diet is eating only one food per meal. So, breakfast might be an apple. It could be multiple apples as long as all of your items are the same food. You wouldn't be able to have an apple with peanut butter.

Depending on how strictly you follow the mono diet, you wouldn’t even be able to eat peanut butter by itself. Most peanut butters are not just made from peanuts. They have oil and sugar added. Sometimes they have salt. Some peanut butters also have fillers, emulsifiers, or other additives.  

What is the theory behind the mono diet? 
The theory is that early man only ate one food per meal. 

I don't believe that, though.  Think about it, no matter where early man lived there was access to more than one food. Humans are believed to have started in the jungles of Africa, where they would have had access to a large number of plants and animals to eat. As they spread into what is now Europe and Asia, they would have continued to have access to a variety of food. Even in desserts, there is more than one food source available.

Are there variations to the mono diet?
Some people adapt the mono diet to be one food group per meal. In this variation, you could eat a banana and an apple at breakfast because they are both fruits. You still wouldn't be able to have an apple with peanut butter because that would be two food groups--fruits and proteins. 

In another variation, dieters eat one food at one meal per day but are allowed to eat multiple meals at other meal times. For example, you might eat a large mixed-food breakfast and a mixed-food lunch but have a lighter dinner of just carrots. 
Does the mono diet help you lose weight? If so, how?
The mono diet can help you lose weight depending on what you eat and how much you eat. The mono diet, like all other restrictive diets, can help you lose weight by decreasing caloric intake.
The mono diet is not necessarily a weight loss diet, though. In theory, someone could follow a mono diet eating only high calorie foods, such as avocados, or eating large portion sizes that do not result in the decreased caloric intake.
Additionally, some people follow the mono diet for reasons other than weight loss. One woman I met thought it helped with digestion. That probably depends on what foods you choose and how you define improved digestion.  Eating a variety of foods at each meal can improve absorption of vitamins and minerals. For example, fats help absorb vitamins A, D, E, and K which aren't always found in fat sources.  
She may have meant she had fewer digestive issues on the mono diet. This is likely due to removing an irritating food, rather than due to eating only one food per meal. For example, it is fairly common for my clients to report digestive symptoms related to eating spices. On the mono diet, people don’t eat spices.  If you're only going to eat one food, you're probably not going to eat a ginger root or a spoonful of turmeric. Thus, following the mono diet helped by removing irritating items.

Are there benefits to the mono diet?
The major benefit I see is that it can help people identify foods that they may be intolerant to. If you only eat yogurt at breakfast and you have GI symptoms afterwards, it is easier to identify yogurt as the culprit than if breakfast had been a yogurt parfait with wheat germ, chocolate chips, almonds, and banana slices. If you do so, I'd recommend keeping a log like the one below.

The mono diet can also help you to focus on eating fewer processed foods, while eating more fruits and vegetables.  Think about it; many junk foods would be eliminated because they have multiple ingredients or multiple food groups. 
What are the problems with the mono diet?
The major con of the mono diet is that you are unlikely to meet your nutrient needs. It is best to eat a variety of foods to get enough vitamins and minerals. If you only eat three foods a day (one at breakfast, one at lunch, one at dinner), you are missing out on food groups and missing out on the nutrients in that food group.  This can be improved by eating more meals a day.
Another problem with the mono diet is that it is probably not sustainable for most people. That is, it'd be hard to follow long-term.
One thing you can take from the mono diet without following it completely is to decrease your food intake in order to lose weight.

Do you recommend the mono diet?
No. I recommend against the Mono Diet.  However, I do know of a dietitian who uses it in her practice for limited periods of time to help identify a possible food intolerance.

If you choose to follow it, I recommend meeting with a dietitian to help determine what foods you should eat to get adequate nutrition. Like with any diet, you should also talk to your doctor about weight loss goals. Your doctor can also write orders for blood tests to monitor you for nutrient deficiencies.  

Tell me: Have you tried the mono diet? If you're a healthcare practitioner, do you use it in your practice?


The information provided in this blog is not intended to replace individualized medical advice provided by your own doctor, dietitian, or other healthcare professional.
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