What is the 5-day Fasting Mimicking Diet Plan?

Have you heard about the Fasting Mimicking Diet? I’ve been intermittent fasting for a while now because I love the easy way it helps me lose weight along with the amazing, science-backed health benefits.

I was bopping around the internet the other day and I came across something called the fasting mimicking diet. Here’s what I found out.

This post may contain affiliate links. My full disclosure policy is sort of boring, but you can find it here.

What is the Fasting Mimicking Diet?

The Fast Mimicking Diet (FMD) is a kind of modified fast. Instead of giving up food completely like a traditional fast, you still get to eat small amounts of certain foods in a way that has been tested to produce the therapeutic benefits of fasting.

The fasting-mimicking diet describes itself as “…a plant-based diet program designed to attain fasting-like effects while providing micronutrient nourishment (vitamins, minerals, etc.) and minimize the burden of fasting.”

The fasting mimicking diet is a great hack to get the benefits of fasting while still providing your body with some food and nutrition.

The creator of FMD, Dr. Valter Longo, PhD (who also happens to be on staff at University of Southern California, also wrote a book on the subject called The Longevity Diet, that was recently published. I’ve read the book and the information is super fascinating.

The FMD program protocol has been patented by Dr. Longo, and is sold in 5-day complete diet kits called the Prolon Diet.

What is the fasting mimicking diet?
The fasting mimicking diet (FMD) is a type of intermittent fasting.

How Does the Fasting Mimicking Diet Work?

If you’ve tried other kinds of intermittent fasting, you’ll be familiar with the same general principle of depriving your body of food to force your body into periods of fat burning and other health benefits like reduced inflammation.

The main difference with the FMD is that instead of eliminating all food for a period of time (fasting window), you are sharply restricting calorie intake for five days at a time. For average healthy participants, Longo recommends repeating FMD cycles every 3 months. The book outlines a different frequency depending on your situation.

But it’s not just the calorie restriction and amount of food you’re allowed to eat on this five-day fasting program – it’s also the type of food and in what ratios that matters.

The first day differs slightly from days two through five. Here is the breakdown:

FMD Cycle

Day 1:

  • Calories: 4.5 to 7.0 kcal/lb of body weight
  • Macros: Protein: 10%, Carbs: 34%, Fat: 56%

Days 2-5:

  • Calories: 3.0 to 5.0 kcal/lb of body weight
  • Macros: Protein: 9%, Carbs: 47%, Fat: 44%

Days 6-30:

  • Eat a healthy, normal diet.

If you are healthy and at your ideal weight, it’s recommended you do the 5-day FMD once every 3-6 months. If you are overweight or have a high risk of diseases like cancer, do the 5-day FMD once every month.

How does the fasting mimicking diet work?
The fasting mimicking diet has results that are backed by science.

The Fasting Mimicking Diet and Science

The benefits of fasting the traditional way have been proven in multiple scientific studies to be real, measurable and significant.

The good news about the FMD is that recent human studies into the protocol have uncovered some dramatic results.

A study funded by the National Institute on Aging showed that periodically cutting daily calories in half for just 4 days improved biomarkers for cancer, heart disease, diabetes and aging with no adverse effects.

Another study of 100 healthy people looked at the effects of the FMD and highlighted some profound results. Half of the subjects followed the FMD five days a month for three months, and half of them (the control group) ate their usual standard diet.

After three months, the FMD group experienced weight loss (including loss of belly fat), drops in blood pressure, blood glucose, and markers of inflammation. In addition, the FMD group also experienced a drop in insulin-like growth factor iGF-1 levels, which is a biomarker for cancer growth.

Can you say, WOW??

Fasting Mimicking Diet Health Benefits

Much like traditional fasting, the fasting mimicking diet has multiple health benefits.

Benefits of the Fasting Mimicking Diet plan.
The fasting mimicking diet shares the same health benefits as intermittent fasting.

Lowering Cholesterol

The same study mentioned above also found that after three months, the FMD group experienced decreased levels of total and bad LDL cholesterol in participants.

Combining the FMD with an overall healthy lifestyle can lower and maintain healthy cholesterol levels and keep your heart healthy.

Reducing Inflammation

The FMD study found the diet to reduce inflammation. Chronic inflammation contributes to several chronic diseases, including diabetes, cancer, heart disease, and, multiple sclerosis.

Because these diseases all have roots in chronic inflammation, this indicates the FMD has the potential to reduce the risk of developing chronic disease.

Improving Brain Health

A 2015 FMD study (4) showed improved cognition and regeneration of neurons in the brain of mice. Markers that track aging were also improved.

Improving Diabetes

The FMD has also been proven to positively affect insulin resistance. Another study (5) showed the maintenance of normal blood sugar levels and there was new generation of insulin-producing beta cells in mice.

Indications are encouraging that the fasting mimicking diet may help control or even reverse diabetes when combined with a healthy lifestyle and regular exercise. Studies have also included the effect of five-day period fasting on autoimmune disease and cardiovascular disease.

How to Start the Fasting Mimicking Diet

The 5-day FMD is based on eating a diet rich in plant-rich whole foods, with an emphasis on nuts and olives, to provide healthy fat. Follow the 5-day plan above and keep these food guidelines in mind.

How to start the fasting mimicking diet plan.
If you like a preplanned diet, you will probably enjoy the structure of the fasting mimicking diet.

FMD Nutrient Tips from The Longevity Diet Book:

The Longevity Diet: Slow Aging, Fight Disease, Optimize Weight

  • No animal-derived products
  • Proteins from plant-based sources
  • Carbohydrates from complex carbohydrate plant sources
  • Fats from “healthy” oils (coconut oil, olive oil) and nuts (almonds, walnuts)
  • Less than 30g of sugars on day 1, and less than 20g of sugars on days 2-5

Of course, on days 6-30, you’ve got to commit to eating a healthy diet to have the benefits really kick in.

If you’re too busy for all the macro counting, the inventor of FMD has patented the system so you can buy everything you need in one meal kit of portioned and pre-packaged foods to help you successfully complete the 5-day Prolon FMD.

Even if you want to DIY your FMD there’s a lot of great information on the Prolon website about the fasting mimicking diet.

Order your own 5-day fasting kit from Prolon.
The FMD purports to provide the same benefits as intermittent fasting, without the actual fasting.

What to Avoid on the Fasting Mimicking Diet

If you’re doing the FMD, you should avoid alcohol, stick to herbal teas, and reduce your caffeine intake to two cups of black coffee or black tea a day.

Strenuous exercise is also not recommended during the 5-day fasting period, but brisk walking is always good.

Is the Fasting Mimicking Diet Right For Me?

Numerous studies have found dramatic benefits with the FMD.

The FMD is recommended for healthy adults in a normal weight range between 18 and 70 years old.

Pregnant women and people with eating disorders should not attempt the fasting mimicking diet. In addition, if you’re on any kind of medication or have health conditions, check with your doctor before you try the FMD to rule out any risk factors.

As always, if you suffer from any chronic conditions, it’s best to consult with your health practitioner before starting any fast.

Have you ever tried the fasting mimicking diet? I’d love to hear your experiences!

Questions about the Fasting Mimicking Diet

What do you eat on a fasting mimicking diet?

The fasting-mimicking diet is low in calories, protein, and carbohydrates, and high in unsaturated fats. It’s designed to mimic a water only fast while still providing essential nutrients you wouldn’t get in a normal fasting state.

A typical meal plan for the FMD is made up of small meals that are made of plant based ingredients such as:

  • Herbal teas
  • Snacks such as olives and kale crackers
  • Vegetable soups
  • Bars made from nuts and seeds
  • Vitamin supplements

Who should not do fasting mimicking diet?

It’s a good idea to get medical supervision any time you try a restrictive meal plan. Especially if you have any medical conditions. If you fall into these categories, you should definitely not try the FMD without a doctor’s approval:

  • History of an eating disorder
  • Pregnant
  • Breastfeeding
  • Children
  • Diabetes or kidney disease – according to the Prolon website, talk to your doctor before starting.
  • Food allergies (check the ingredient lists before you begin)
Prolon Fasting Mimicking Diet Plan 5 day kit.
The FMD is high in fat, low in carbohydrates and may not be suitable for everyone.

How often should you do the fasting mimicking diet?

The diet’s creator recommends repeating the diet for 1-6 months if you’re trying to lose weight. If you’re already at your ideal weight, it’s recommended to repeat at least every 6 months to reap the potential health benefits.

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

ProLon claims the FMD results in an average weight loss of five pounds. Following the fasting mimicking diet helps you lose weight while preserving lean body mass.

Does the fasting mimicking diet put you in ketosis?

Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose. During ketosis, your liver produces ketones using your fat stores as an alternative to using glucose as a source of energy. Since the fasting mimicking diet is a prolonged fast, is should put you in ketosis.

What are drawbacks to the fasting mimicking diet?

While the FMD may be an effective way to lose weight and gain health benefits, it is very pricy. The cost may be a drawback because it’s recommended you follow the program at least every one to six months.

Can you drink coffee on the fasting mimicking diet?

Black coffee is allowed on the FMD, but it’s recommended you only have two cups a day. Herbal teas and water are allowed. Black coffee doesn’t have significant calories or nutrients that would break a fast, and can suppress your appetite, which is helpful during fasting.

Is the fasting mimicking diet vegan?

All current versions of ProLon’s fasting mimicking are suitable for vegetarians. Some of the FMD plan’s nut bars contain honey, so may not be suitable for vegans.

Can you drink lemon water on the FMD?

Water with a squeeze of lemon juice contains almost no calories and has zero sugars. Because of this it won’t raise insulin levels so you can safely drink it without breaking your fast on the FMD.

Is the fasting mimicking diet the same as intermittent fasting?

Not exactly…intermittent fasting is dividing your day up into period of eating (eating window) and fasting (fasting window). The different types of intermittent fasting all focus on how long each window is. For example, in 16/8 fasting, there are 16 hours of fasting with 8 hours of eating.

With the FMD, calories are restricted, but there are no true fasting windows. The fasting mimicking diet promotes eating small, calorie-restricted meals made up of specific nutrients and macros.

Can the fasting mimicking diet help dementia?

According to animal studies, the answer is yes. Researchers found that mice who went through several cycles of FMD exhibited less Alzheimer’s disease damage. In addition, the mice had better cognitive performance than those with a standard food intake.

More human studies need to be done, but it appears that the FMD could be protective against age-related diseases and can promote healthy aging.

Is the FMD the same as the keto diet?

The ketogenic diet consists of very low carbohydrates, high fats, and a normal intake of protein. It is not a calorie restricted diet and can be done for weeks at a time. The FMD is a calorie restricting plan which lasts only 5 days.

Both plans may put you into ketosis, but the way you get there is quite different. Both plans may also have the same side effects (hunger, fatigue, etc. )

Are there side effects to the fasting mimicking diet?

The side effects to expect are the same one would experience in trying any other type of intermittent fasting. If you’re used to fasting, you may not experience any of these, but if you’re new to this way of eating you may experience:

  • Hunger
  • Fatigue
  • Dizziness
  • Cravings
  • Headache
  • Digestive issues
  • Irritability and mood changes
  • Bad breath
  • Sleep disturbances

Want To Remember This Post About The Fasting Mimicking Diet? I’d Love It If You’d Pin It To Your Favorite Healthy Living Pinterest Board And Pass It On!

The fasting mimicking diet plan promises to give you all the benefits with only a few days of fasting at a time.