What's a Mono Diet and Why It Isn't Recommended?

The mono diet is one in which only one type of food is consumed at each meal. It is used to lose weight quickly, but in reality it has many disadvantages.
What's a Mono Diet and Why It Isn't Recommended?

Written by Editorial Team

Last update: 08 February, 2023

Restrictive food plans like the mono diet don’t usually work in the medium and long term. In fact, they even bring adherence problems. Moreover, efficient weight loss depends on other factors, such as regular physical exercise.

It’s advisable to first promote muscle gain so that it is easier to maintain an energy deficit afterward. Other healthy habits should also be implemented. But back to the main topic… what are the problems with the mono diet?

How is the mono diet carried out?

The truth is that there’s contradictory information about the mono diet. Some people claim that only a certain food can be consumed throughout the day. Others claim that this choice is made at each meal.

In any case, we are talking about a very restrictive approach that will lead to significant nutritional deficits. The first thing that will happen – among other things – is a deterioration of muscle mass. To maintain muscle mass, it’s essential to ensure a minimum daily protein intake, which is difficult with a single-food diet.

According to research published in the Annals of Nutrition & Metabolism, at least 0.8 grams of protein per kilogram of body weight are needed for muscle function to be carried out properly. In athletes, the requirements are easily multiplied by 2 or 3 times.

The mono diet.
The mono diet is restrictive and tends to cause nutritional deficits and puts health at risk.

How to follow a mono diet?

There are several types of mono diets, and so there are different alternative approaches. However, it’s often based on a single type of food at each meal; this can be potatoes, apples, eggs, etc.

However, there’s also the option of including more variety by using foods from the same group. Thus, it can cover various types of cereals, lean meats, vegetables, or fruits.

There aren’t any guidelines about how long it’s safe to follow it. But, due to its restrictive nature, it cannot be for more than two weeks. Otherwise, nutritional deficits will begin to compromise health.

By this time, you are likely to have lost weight. And, although this is striking, it’s actually accompanied by other negative effects on the physical and mental state.

After two weeks, you gradually introduce other foods such as soups, salads, and smoothies. Then, the next step is to return to a balanced and varied diet, with foods from all food groups and without restrictions.

Among the most common foods to include in the mono diet are potatoes, eggs, apples, bananas, chocolate, and grapefruit. Nevertheless, it is also possible to do it using meat or legumes.

Does the mono diet help you lose weight?

Contrary to what its defenders affirm, the mono diet is not an efficient option to lose weight. True, you can lose a few pounds with this approach, but part of them will be glycogen and liquids.

In the meantime, it’ll destroy part of the muscle tissue, which is bad for your health and the state of body composition in the medium term. As a result, resuming your normal diet will lead to an increase in weight, even more than before you started this diet.

This type of restrictive diet usually produces rebound effect, and the person will end up in a worse place than when they started. It’s always better to follow good habits and not miracle plans.

Contraindications of the mono diet

Apart from the loss of muscle mass and the subsequent rebound effect, the mono diet has another series of contraindications that are worth knowing about. It’s key to note that an insufficient intake of fatty acids conditions the hormonal environment.

For example, if fats aren’t consumed in optimal amounts, testosterone levels will be depressed, which affects vitality, strength, and health, according to a study in The Journal of Steroid Biochemistry and Molecular Biology.

There will also be problems in controlling the creation of free radicals, as the supply of antioxidants will not be sufficient. This results in an acceleration of the aging process and an increased risk of developing chronic pathologies.

Gradually, people experience dysfunction at the mitochondrial level and increased inflammation, leading to cellular damage at the DNA level.

Other options for weight loss

When it comes to weight loss, it isn’t necessary to take such a restrictive approach. It’s preferable to cover protein requirements in the context of a varied, albeit slightly energy-deficient, diet.

What will really make the difference is physical activity. It’s very difficult to lose weight by cutting calories alone. However, you must implement other healthy habits, such as:

  • Reducing the presence of processed foods in the diet.
  • Improving the quality of sleep.
  • Increasing water consumption.
  • Introducing strength work in the routine.
Losing weight.
Weight loss requires a multidisciplinary and personalized approach. That is why miracle diets are not a good option.

In short, the mono diet is not a good choice for weight loss. It’s a restrictive and unsustainable diet that will lead to deficits in essential nutrients. Thus, it will cause alterations in the normal functioning of the body. In turn, it raises the risk of chronic diseases and premature aging.

Any diet with miraculous characteristics tends to have side effects on health. Although they promise great results in a short time, they often lead to a subsequent rebound effect, in addition to several dangers during their implementation.

It’s better to think in the medium term and carry out a sustainable option that generates adherence. And given the complexity of each body, it’s best to get a personalized plan from a nutrition professional.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


  • Richter M, Baerlocher K, Bauer JM, et al. Revised Reference Values for the Intake of Protein. Ann Nutr Metab. 2019;74(3):242-250. doi:10.1159/000499374
  • Whittaker J, Wu K. Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies. J Steroid Biochem Mol Biol. 2021;210:105878. doi:10.1016/j.jsbmb.2021.105878
  • Singh RK, Kumar P, Mahalingam K. Molecular genetics of human obesity: A comprehensive review. C R Biol. 2017;340(2):87-108. doi:10.1016/j.crvi.2016.11.007
  • Tahreem A, Rakha A, Rabail R, Nazir A, Socol CT, Maerescu CM, Aadil RM. Fad Diets: Facts and Fiction. Front Nutr. 2022 Jul 5;9:960922. doi: 10.3389/fnut.2022.960922. PMID: 35866077; PMCID: PMC9294402.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.