Valter Longo is perhaps most well known for his work on fasting. Specifically his 5 day fast mimicking diet. However, he doesn’t expect you to fast all year round! To provide a solution whilst you’re not fasting, Valter has created The Longevity Diet (book). It details a diet with a proven track record of facilitating people to become centenarians. This post will be split into two sections:

  • Fast Mimicking Diet – Valter’s fasting diet details
  • The Longevity Diet – Valter’s suggestions for how to eat daily

Fast Mimicking Diet

The fast mimicking diet is designed so you get the benefits of a 5 day water fast, whilst still being able to eat something each day. Valter and his colleagues at USC (University of Southern California) have patented and designed an out of the box 5 day ‘fast mimicking diet’ (FMD). This can be purchased in the USA from for $249, and in UK from for £225. For many people, the easiest way to do the fast will be to simply purchase it and follow the instructions.

Fast Mimicking Diet DIY – Method 1

For those who prefer not to spend $249 on 5 days of “food”, or for some other reason, would like to DIY it, it’s definitely possible. In order to replicate the same diet and results, you will want to start by knowing the exact calorie and macronutrient composition of the diet.

The “original” 2015 Cell Metabolism paper that described the diet quoted the composition as:

Day 11,090 calories10%56%34%
Day 2-5725 calories9%44%47%

To quote the specific section in the paper:
“The human fasting mimicking diet (FMD) program is a plant-based diet program designed to attain fasting-like effects while providing micronutrient nourishment (vitamins, minerals, etc.) and minimize the burden of fasting. It comprises proprietary vegetable-based soups, energy bars, energy drinks, chip snacks, chamomile flower tea, and a vegetable supplement formula tablet. The human FMD diet consists of a 5 day regimen: day 1 of the diet supplies $1,090 kcal (10% protein, 56% fat, 34% carbohydrate), days 2–5 are identical in formulation and provide 725 kcal (9% protein, 44% fat, 47% carbohydrate).

Since that paper was written, Valter and his team created the “off the shelf” FMD diet box (mentioned above). The calorie and macronutient composition of its consituents does differ slightly:

Day 11,116 calories13% (26g)36% (70.5g)50% (98g)
Day 2700 calories11% (15g)28% (37g)60% (79g)
Day 3710 calories14% (18g)30% (39g)56% (72g)
Day 4700 calories11% (14g)28% (37g)61% (81g)
Day 5736 calories13% (18g)29% (39.5g)57% (77g)

This data was taken from a combination of 2 sources; the detailed box contents and some calculations on the contents. By the way, if the percentages in the above table don’t always add up to 100%, it’s because about 1% is split into fractions between the 3 macronutrient types – and I’ve left off the decimal points for simplicity.

Whilst the calories/macronutrients differ slightly from the 2015 Cell Metabolism paper to the Prolon FMD box itself, there maintains an overall pattern.

  • Day 1 is always higher in nutritional value, at around 1,100 calories – with protein at 13% or lower.
  • Days 2-5 are always around 700 calories with protein kept below 15% of total nutrients.
  • Lastly, whilst the Prolon FMD diet has higher carbohydrate content than the Cell Metabolism paper used, it doesn’t go above 61% carbs.

Keep those above key points in mind with your DIY FMD diet, and you won’t go far wrong. Perhaps key is to keep the protein content below 15%, that way you keep IGF-1 levels down; thought to be a core part of the fasting benefits.

Beyond calories and macros, the Prolon FMD box adds:

  • Days 2 to 5 adds a potassium fortified drink, because fasting can reduce potassium levels, so supplementing this avoids any side effects
  • Days 1 to 5 add a multivitamin daily
  • Days 1 & 5  add 200mg DHA oil each day

I’ve mentioned both of these links above already, but will mention them again in case they help you formulate your FMD diet:

  • The first is a set of tables that provide the blow by blow macros and calories for each day of the official FMD diet.
  • The second is details of the individual products in the FMD diet, with their respective nutritional information.

The Longevity Diet

In creating The Longevity Diet, Valter travelled around the world studying centenarians. He put together a formula he calls the Five Pillars of Longevity. Diet principles had to clear all 5 of the pillars to be viewed as viable long term possibilities. For example, take the recent fad of ketogenic diets. Whilst ketosis is very successful at weight loss, and has positive health benefits in clinical trials, there are no populations of people that have eaten this diet and regularly lived to become centenarians. Pillar 4 requires there to be evidence that centenarians have eaten a particular diet. Now, that doesn’t mean it isn’t possible for people to eat a ketogenic diet their whole life and live past 100, it just means we don’t yet have a long enough timeline of experimentation yet. For sure, there will be some that are happy to take risks and live on untested diets. But others will feel more at ease to stick with the tried and tested.

Below lets look at three key aspects to Valter’s book. Firstly, lets compare this diet to one you may be familiar with; the Mediterranean diet. Then lets look at his 5 pillars of longevity approach and what that means. Lastly, lets look at the longevity diet rules for eating.

Differences Between the Optimal Mediterranean Diet and the Longevity Diet

 Mediterranean DietLongevity Diet
Olive OilHighHigh
Unrefined CerealsHighHigh
FruitsHighLow until old age, then higher
CheeseModerateAbsent/very low
YogurtModerateLow until age 65-70, then moderate
Meat & meat productsLowAbsent/very low
MilkLowAbsent/very low
EggsLowAbsent/very low until age 65-70, then moderate
ButterLowAbsent/very low
Protein levelsNot addressedLow until age 65-70, then moderate
General food consumptionNot addressedNormal until age 65-70, then sufficient to maintain a healthy muscle mass
Time-restricted feedingNot addressed11-12 hr eating window central to plan

Table credit – The Longevity Diet Book by Valter Longo

It’s worth pointing out some key aspects of the diet:

  • It emphasises low protein. No animal meat, with fish around 3x per week (the guideline is 0.31 to 0.36 grams of protein per pound of body weight per day)
  • Essentially no dairy, perhaps just a small amount
  • It uses an 11-12 hour eating window

The 5 Pillars of Longevity

Image source: The Longevity Diet Book by Valter Longo

Pillar 1: Basic/juventology research

This pillar covers the scientific lab work done on simple cells and animals. Helping to establish the fundamental properties of organisms and how dietary interventions affect them. Every theory starts off here, and if successful, could later make its way to human tests.

Pillar 2: Epidemiology

This is the study of what happens to specific groups of people “in the wild”. For example, the first known epidemiological study was by John Snow (GoT anyone?!). He noticed that two areas of London had significantly higher death rates than elsewhere, and was able to pin it down to a specific water pump that provided both areas with water. By using Chlorine to clean the water, he solved the problem. So essentially Valter believes that we need to cross-check our theories with active populations to understand how they affect people.

Pillar 3 – Clinical studies

Clinical studies are the next steps after looking at both basic lab research and epidemiological studies. And are essential for comparing a theory against a control group. So for example, you could test a particular diet intervention in one group of subjects, and have another group who are similar in age, weight etc., but don’t follow the particular diet intervention. That way you can tell what effect, if any, the intervention has.

Pillar 4 – Centenarian studies

This pillar essentially covers epidemiological studies of specific “blue zone” populations. Blue zone just refers to an area of people that commonly live past 100. Even if a diet makes it past the first 3 pillars, its important to look at real world longitudinal studies for confirmation a diet is safe and effective long term. In order to do this, Valter studied long-lived populations in Ecuador and southern Italy and consulted the work of his colleagues focusing on other very long-lived populations.

Pillar 5 – Studies of complex systems

Valter describes this last pillar as a way of viewing the complexity of a human body as a whole. Taking simple models of function/loss of function, and plugging them into the wider system to see how they operate. Helping to understand the complex interactions between food, cellular damage and ageing. I don’t think I’ve done a great job of describing this, and I think it comes down to its level of abstraction. Its more a method of thinking about the human body, versus a formulaic methodology (as with the previous 4).

The Longevity Diet Rules:

1. Eat a mostly vegan diet with some fish:
Strive for a 100 percent plant- and fish-based diet, but limit fish consumption to two or three meals a week and avoid fish with high mercury content. After age sixty-five to seventy, if you start losing muscle mass, strength, and weight, add more fish and fruit and introduce animal-based foods like eggs, cheese, and yogurt made from sheep’s or goat’s milk.

2. Consume low but sufficient proteins:
Consume approximately 0.31 to 0.36 grams of protein per pound of body weight per day. If you weigh 100 pounds, that is about 31 to 36 grams of protein per day, of which 30 grams should be consumed in a single meal to maximize muscle synthesis. If you weigh 200 pounds and have 35 percent body fat, 60 grams of protein per day are instead sufficient, considering that it is the lean body mass that utilizes most of the proteins. Protein intake should be raised slightly after age sixty-five to seventy in individuals who are losing weight and muscle.

3. Minimize bad fats and sugars, and maximize good fats and complex carbs:
The diet should be rich in “good” unsaturated fats, including those from salmon, almonds, and walnuts, but very poor in “bad” saturated, hydrogenated, and trans fats. Likewise, the diet should be rich in complex carbohydrates, such as those provided by whole bread and vegetables, but poor in sugars and limited in pasta, rice, white bread, fruit juices, and fruits containing carbohydrates that are easily converted into simple sugars. Finally, the diet should be low in animal proteins but relatively high in vegetable proteins, in order to minimize the former’s negative effects on diseases and maximize the latter’s nourishing effects.

4. Be nourished:
The body needs protein, essential fatty acids (omega-3 and omega-6), minerals, vitamins, and sufficient sugar to fight the many wars going on inside and outside cells. To be sure you get enough nutrients, every three days take a multivitamin and a mineral pill, plus an omega-3 fish oil soft gel purchased from a reputable manufacturer.

5. Eat at the table of your ancestors:
Consume a variety of foods to take in all the required nutrients, but choose the ones that were common on the table of your parents, grandparents, and great-grandparents, so long as they are included in the Longevity Diet.

6. Eat twice a day plus a snack:
Unless your waist circumference and body weight are in the normal or low range, it is best to eat breakfast plus one other meal a day and one low-calorie, low-sugar, nourishing snack. If your weight or muscle mass is too low, then eat three meals a day plus a snack.

7. Time-restricted eating:
Restrict your eating to eleven to twelve hours or less per day. For example, if you eat breakfast after 8 a.m., finish dinner before 8 p.m. Shorter periods of feeding (ten hours or less) have been shown to be even more effective in promoting health, but they are much more difficult to comply with and may increase the risk of side effects, such as the formation of gallstones.

8. Periodic prolonged fasting-mimicking diets:
People who are under seventy years of age, not frail or malnourished, and free of certain diseases should undergo five-day periods during which they consume a relatively high-calorie fasting-mimicking diet. An FMD may also be appropriate for older people, but only if needed and if a medical doctor recommends it.

9. Follow steps 1 through 8 in such a way that you reach and maintain a waist circumference of less than 35.5 inches for men and less than 29.5 inches for women. This is higher than the ideal 33 inches and 27 inches cited earlier, but it is more realistic and should still be very effective in reducing disease risk while avoiding malnourishment.

Exercise for Longevity

Walk fast one hour per day. Take the stairs instead of escalators and elevators, even if you have to go up many flights. On the weekend, try to walk, even to faraway places, but avoid polluted areas. Do moderate exercise for 2.5 hours a week, some of it in the vigorous range. Do weight training or weight-free exercises to strengthen muscles (combined with 30 grams of protein intake following the weight training).

Posted by Alex

Hi, I’m Alex, a writer with a broad interest in nutrition, hormones, cancer prevention and gerontology (study of ageing). I write this blog to answer questions I myself have had at one stage or another. With the hope that others find it useful.


  1. Alex, I appreciate your job here in dissecting Valter Longo’s FMD. I have one question though: how did you determine the protein/fats/carbs ratios?
    From his book ‘The longevity diet’ and the Prolon patent application + article I interpreted these ratios to be about 10-45-45 (in days 2 to 4).
    I’m posting an excerpt from his article in ‘cell metabolism’, where the pilot controleld trial in humans is described:

    Human Diet
    The human fasting mimicking diet (FMD) program is a plant-based diet
    program designed to attain fasting-like effects while providing micronutrient
    nourishment (vitamins, minerals, etc.) and minimize the burden of fasting. It
    comprises proprietary vegetable-based soups, energy bars, energy drinks,
    chip snacks, chamomile flower tea, and a vegetable supplement formula tablet
    (Table S4). The human FMD diet consists of a 5 day regimen: day 1 of the diet
    supplies 1,090 kcal (10% protein, 56% fat, 34% carbohydrate), days 2–5 are
    identical in formulation and provide 725 kcal (9% protein, 44% fat, 47%


    1. Hi mccoy, thanks for the comment, it was a good one.

      With regards to the macronutrient ratios, you’re absolutely right, the numbers in the 2015 Cell Metabolism paper do differ from the numbers I had used above.

      I had got mine from breaking down the composition of the Prolon FMD box contents.

      What I’ve done since your comment is to lay out both the 2015 Cell Metabolism’s macronutrient rations AND the Prolon FMD boxes’ macronutrient ratios. And then have commented on the core commonalities between them. Such as:

      • ~1,100 calories on day 1, ~700 calories on days 2 to 5
      • Staying under 15% protein, and under 60% carbohydrates

      Hopefully that builds up an overall picture for readers of what they should be aiming for, without making things too confusing.

      If you get a chance to re-read that section of the post – do let me know if you have any further thoughts for improving it.


  2. What are the recommended macros for maintenance with this way of eating? Besides protein which has already been mentioned. Thanks


    1. Hi Vaun, thanks for your message.

      Day 1, you’re aiming for 1,100 calories. 15% protein, 50% carbs, 35% fat
      Day 2,3,4 & 5 you’re aiming for 670 calories. 15% protein, 60 carbs, 25% fat

      I’ve rounded these slightly, so if you want to compare them to the exact calorie/macro numbers the FMD diet uses, you can use this link.


  3. I am a female five feet one inch who weighs 220 and has thyroid condition. I want to know if I can fast for two weeks.


    1. Hi D Yueng. With regards to your thyroid condition and fasting, that is a question best left to your doctor. Especially if you’re looking to do an extended fast in the region of 2 weeks. I could imagine a number of possible complications when combining thyroid issues (and its medication) with long periods of not eating. So yes, as I mentioned, do seek specialized medical advice for this question.

      For anyone relatively new to fasting, I would suggest taking it in stages. Start off with a 2-3 day fast, perhaps repeat that a couple of times, then move to 5 days, and so-forth. Firstly, like anything that is practiced, it does get easier over time. And secondly, this gives you adequate experience to learn how to manage your time, energy and wellbeing as you go deeper into the fasting territory.

      Jumping straight to a 7 or 14 day fast could come with unnecessary risks.


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