Fasting has always been a popular way to lose weight. But what about the health issues that accompany it? Often, people do not think about the possible adverse effects of this method. That is why researchers have developed a new method called the fasting-mimicking diet that lets you eat food while fasting. Yes, you read it right. This diet does not follow the conventional fasting methods but a modified version that involves calorie-restricted fasting.

But how can you eat and fast at the same time? How does it affect your health? Well, we have all the answers in this article. Read on to know more about this trending weight loss method, its pros, cons, and more.

What Is The Fasting Mimicking Diet?

 The fasting mimicking diet is a modified fast where you consume small amounts of food that offers the right balance of proteins, fats, and carbohydrates. It is all about “tricking” your body into believing you are fasting. It helps reduce the hunger pangs that you may experience during fasting while also maintaining the fasting state. As a calorie-restricted meal, it includes mostly plant-based ingredients like fruits, nuts, vegetables, olives, seeds, fruits, and herbal teas. It can be seen as an effective fasting technique that people can actually sustain. With this mimicking technique, you can bid goodbye to the fatigue, headaches, hunger pangs, and cravings that generally come along with conventional fasting.

Though there are several ways to find that sweet spot between too much and too little food, there is only one commercially available fasting mimicking diet plan available on the market.

Pioneered by Dr.Valter Longo, a biogerontologist and cell biologist at the University of Southern California (USC), L-Nutra’s ProLon is the commercial version of the FMD approach. He has conducted 20 years of extensive research on food restrictions, calorie intake, and how they may help one lose weight, be healthy, and prevent diseases.

According to the diet plan developed by Dr. Longo, the ProLon fast only lasts for five days every month. They deliver five boxes of food for each day that are to be eaten in a particular order. The meal kit may include bars, drinks, crackers, supplements, soups, and olives. They may also contain instructions for maintaining hydration levels with water and decaffeinated tea.

Are you still confused about how FMD works? Let us help you clear your doubts.

How Does The Fasting Mimicking Diet Work?

The fasting-mimicking diet mainly triggers autophagy (breakdown of old cells). This is a never-ending cleaning process that happens in the cells of our bodies. It can be called a cellular “recycling factory” that promotes energy efficiency and removes non-functional proteins and organelles (1). The more clean-up, the better for your health. Thus, Dr. Longo and his team formulated a diet to increase autophagy in the cells.

This calorie restriction mimics the body’s physiological response to traditional fasting methods, such as cell regeneration, decreased inflammation, and fat loss.

According to FMD, their prepackaged meals provide between 34% and 54% of the normal caloric intake with a composition of at least 9%–10% proteins, 34%–47% carbohydrates, and 44%–56% fat (2). This calorie restriction mimics the body’s physiological response, and the body starts using ketones produced from fat reserves. As the body metabolizes fat reserves to produce ketones, it is said to start losing weight.

This is how fasting mimicking helps your body lose weight. However, every method has two sides. So, let’s learn about the pros and cons of this diet.

Pros Of The Fasting Mimicking Diet

The fasting mimicking diet is one of the few research-backed diets with several other benefits than just weight loss. Some of them are as follows:

1. May Promote Weight Loss

According to a study led by Dr. Longo, people who completed three cycles of the ProLon fasting mimicking diet over three months showed considerable change in their weight. It reduced body weight and trunk fat, and the participants lost an average of 2.6 kg (3).

2. May Reduce Cholesterol

Research conducted on the fasting mimicking diet also evaluated the participants’ blood sugar and cholesterol levels. It found that the fasting-mimicking diet can help reduce blood sugar and cholesterol levels. Cholesterol dropped by 20 mg/dl, and blood sugar level reduced to the normal range during the course of the study (3).

3. May Reverse Diabetes

According to a study conducted on mice, FMD promotes the regeneration of damaged pancreatic cells, improves healthy insulin production, and reduces insulin resistance. The results showed more normal blood glucose levels in mice with type 2 diabetes (4).

4. May Regulate Blood Pressure

The study led by Dr. Longo also found that following this diet for three months may help regulate blood pressure. As per the results, the participants’ systolic blood pressure dropped by 4.5 mmHG, while their diastolic blood pressure dropped by 3.1 mmHg (3). Also, it was found that they retained the results even after returning to their normal diet.

5. May Reduce Autoimmune Diseases

The fasting mimicking diet can influence lymphocytes and positively impact autoimmune diseases like rheumatoid arthritis, type 1 diabetes, and multiple sclerosis. It has been shown to promote anti-inflammatory effects that may contribute to reversing autoimmune disorders by killing damaged and old cells and replacing them with young and functional ones (5).

6. May Improve Cognition

According to research conducted on mice, FMD can help improve motor coordination and memory. It helps accelerate the growth and development of nervous tissues, resulting in improved cognitive functions (6).

Cons Of The Fasting Mimicking Diet

Though the fasting mimicking diet benefits your health, it may also have temporary side effects. Since it is a program based on dietary changes, people may experience some common symptoms such as:

  • Fatigue
  • Headache
  • Hunger
  • Dizziness
  • Sugar cravings
  • Lightheadedness
  • Musculoskeletal pain
  • Nausea
  • Bloating
  • Cramping
  • Constipation
  • Diarrhea
  • Gassiness

However, these side effects are common and tolerable by most people. Consult a doctor if these effects persist post the diet period.

StyleCraze Says

Avoid strenuous activities or exercises requiring more energy while following a calorie-restricted diet. You may go walking or do warm-up exercises to stay active.

Since each person experiences fasting differently, its effects may not be the same for everyone. It is also best to learn whether it is safe for you before starting this diet program. Learn more about who should avoid this diet in the next section.

Who Should Not Follow The Fasting Mimicking Diet?

The fast mimicking diet is considered a safe diet for most people who want to lose weight and improve their overall health (7).

However, certain groups should not opt for this diet. According to the ProLon guidelines, you should not use any FMD products if you:

  • Have dietary restrictions.
  • Have a fever, cough, or diarrhea.
  • Have signs of an active infection, or are at risk for recurrent infection.
  • Are underweight, breastfeeding, or pregnant.
  • Have an eating disorder.
  • Are allergic to nuts, soy, oats, sesame, or celery/celeriac.
  • Are under the age of 18.
  • Are over the age of 70 (unless you are under the supervision of a healthcare provider).

Although fasting for a short period of time is safe, it is always best to consult your doctor before starting the diet to check if it is right for you.

The Fasting-Mimicking Diet Plan

The fasting mimicking diet is a plant-based diet that provides both macro and micronutrients to reduce the side effects of fasting. The guidelines are as follows (3):

  • Day 1: ~4600 kJ (11% protein, 46% fat, ad 43% carbohydrate)
  • Days 2 to 5: ~3000 kJ per day (9% protein, 44% fat, and 47% carbohydrate).

Since the diet plan formulated by Dr. Longo is the only commercially available and clinically studied approach, it is advised to consult a healthcare professional to ensure safety before you follow this diet. However, you can follow a DIY meal plan with the recommended calories and nutrients mentioned above. Below, we have formulated a sample meal plan for you.

Day 1


  • Prepare a smoothie with 100 g avocado, 1 cup spinach, 1 medium banana, and 1 cup of unsweetened almond milk.



  • Prepare a salad with 2 cups of mixed greens like spinach, lettuce, and chicory, 150 g tomato, 85 g carrots, 100 g cucumber, ¼ cup cooked brown rice, 40 g avocado, and 5 olives. You can also add 1 teaspoon of olive oil to it.
  • A sprinkle of herbs and a squeeze of lemon will add flavor to the salad.
  • Five almond crackers.


  • Prepare a vegetable rice bowl with 170 g broccoli, 14 g sun-dried tomatoes, 30 g baby bella mushrooms, ½ cup brown rice, 1 square of dark chocolate, and 4 oz kombucha.

Days 2-5


  • Half cup of green tea or water with half a packet of LMNT electrolytes and 1 teaspoon of inulin to reduce hunger pangs.


  • Prepare a salad with 2 cups of mixed greens, 100 g tomato, 90 g carrots, 40 g avocado, 100 g cucumber, 5 olives, and 1 teaspoon of olive oil. You can squeeze in lemon juice and sprinkle salt, pepper, and herbs for added flavor.


  • Five almond crackers, 10 olives, and 1 ½ cup of green tea.


  • Prepare a salad with 170 g broccoli, 30 g baby bella mushrooms, ½ cup brown rice, 14 g sundried tomatoes, 4 oz kombucha, 2 teaspoons of olive oil, 8 olives, and 1 square of dark chocolate.

StyleCraze Says

You can use fitness and calorie tracking applications to keep track of your calorie intake and formulate a plan based on your food patterns.

You can follow this meal plan or formulate one for yourself with more varied items and a strict check on the daily calorie requirements. Now that you know how to make a diet plan, let us show you how FMD differs from intermittent fasting.

Fasting-Mimicking Diet Vs. Intermittent Fasting: Key Comparisons

The major difference between the fasting mimicking diet and intermittent fasting is that you can consume small amounts of food throughout the day that provide the three important macronutrients in FMD. In contrast, in intermittent fasting, you cannot consume any food during the fasting window.

However, when you eat, you do not have any food restrictions in intermittent fasting, while there are calorie restrictions in FMD. Calories are not counted in intermittent fasting during the eating window, while you are only allowed to consume specific foods in FMD.

The Bottom Line

Fasting is an old technique many people employ to shed some pounds quickly. But, it may not always be healthy and recommended for everyone. Fortunately, you can trick your body into shedding some pounds by following this calorie-restricted fasting-mimicking diet. Apart from helping you lose weight, it can help improve your overall health by regulating glucose, blood pressure, and cholesterol levels and reducing the risk of autoimmune diseases. However, it is always best to consult a medical professional before starting this program to check whether your body is ready for it.

Frequently Asked Questions

Is fasting mimicking better than fasting?

Fasting mimicking is better than fasting as it allows you to eat low-calorie foods to prevent weakness and hunger pangs. This method also helps improve overall health by regulating blood pressure, cholesterol, and blood sugar levels and reducing the risk of autoimmune diseases.

How long can you do the fasting mimicking diet?

For best results, you can follow this diet for 5 days a month for up to 6 months. However, consult your doctor after 3 months before continuing with the diet.

How much weight can you lose on the fasting mimicking diet?

You may lose 2 to 3 kg while following the fasting mimicking diet.

Key Takeaways

  • The fasting-mimicking diet is a plant-based, calorie-restricted meal plan that can be followed five days a month.
  • On this diet, you consume small amounts of food throughout the day that offer the right balance of proteins, fats, and carbohydrates.
  • Other than weight loss, it may help in treating diabetes and controlling blood pressure and cholesterol levels.


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. Autophagy: Cellular and molecular mechanisms
  2. A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance, and healthspan
  3. Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease
  4. Fasting-mimicking diet promotes Ngn3-driven β-cell regeneration to reverse diabetes
  5. Nutrition and fasting mimicking diets in the prevention and treatment of autoimmune diseases and immunosenescence
  6. A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance and healthspan
  7. Safety and feasibility of fasting-Mimicking diet and effects on nutritional status and circulating metabolic and inflammatory factors in cancer patients undergoing active treatment

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