Fast Mimicking Diet DIY – Get Healthy in Just Five Days a Month

Last Updated on: 16th November 2023, 07:59 pm

Fast mimicking diet DIY

Going without food can significantly improve your health.

But it’s hard to be hungry all the time.

That’s why the Fast Mimicking Diet (FMD) has been called the ultimate way to fast.


The Fasting Mimicking diet is a way to trick your body into giving you the benefits of fasting … while still eating food.

Yep, you heard that right! No more long stints without eating…

Of course, there are rules. You have to invest about five days every month on the diet and there are strict guidelines about what you can and can’t eat during the period.

That said, it’s a small price to pay to get the benefits.

Benefits of the Fasting Mimicking Diet

Before we get started, some good news. This is not just a way to lose weight.

Studies have shown that if you stop or reduce food for three days or more, it throws your body into a kind of “repair” mode – rejuvenating and killing damaged cells. This can deliver a bunch of health benefits including:

  • reduced body weight, trunk, and total body fat1
  • lowered blood pressure2
  • decreased insulin-like growth factor 1 (IGF-1)2
  • improved cholesterol levels2
  • reduced signs of dementia (in mice)3
  • increased longevity (in mice)4

How does it work?

Like most diets, the FMD works by restricting calories restriction. One important difference is that that slows down the ongoing “growth” pathways in our cells to make time for repair and regeneration of healthy stem cells.

The problem here is that the modern diet means we eat too much. This over eating means our bodies don’t get the chance to slow down and relax and heal themselves.

Fast Mimicking Diet versus Keto Diet

Wait, if I’m already doing a keto diet, can FMD help me?

If you want to lose weight, fast mimicking and keto can deliver great results by teaching your body to burn fat as fuel, they just do it in different ways.

Fast Mimicking

While it’s called fast mimicking, you don’t get away with eating your usual amount. It’s based on restricting calories, you’re eating about 50% of your usual amount on the first day and 40% for the next four days.  


With the Keto Diet, you can pretty much eat as much as you like whenever you like. The key to it is that the balance of high-fat and low carbs. When you start burning keytones and replace carbs with fat, that regulates how much you want to eat.

The keto diet versus fast mimicking diet

Ok, I’m convinced! How do I get started?

Make sure you’re healthy

Before we get int the detail, as always, you should be cautious when making any changes to the way you eat, and if an any doubt, check with your doctor, especially if you’re on any medication, have health problems such as diabetes or blood pressure, you have a history of eating disorders, or you’re over 65 years old.

This process is likely to make you a little bit hungrier than usual, perhaps have less energy, but anything other than that, please stop. This is designed to get your body into better shape, not to make anything worse.

FMD in a box

FMD was developed by Valter Longo, PhD – USC Leonard Davis School of Gerontology, who sells the ProLon Fasting Mimicking Diet as a five-day pre-packaged meal kit. But the kit is expensive, costing nearly $200 per meal box, so many choose to figure out the principles of FMD and do it themselves.

(Think of it as mimicking the fast mimicking diet – DIY style!)

This is totally doable but can be overwhelming when you are starting out.

That’s why we’re here!

The rest of this article is going to give you a Fast Mimicking Diet DIY cheat sheet and allow you to do it yourself.

FMD – the do-it-yourself approach

Sometimes the best things in life are free.

If you want to understand how to copy Dr Longo’s approach, the video below where he shares with Dr Steven Gundry is a good start.

It’s a long interview (55 minutes), and is a wide-ranging conversation that covers everything from plant based eating, to longevity. so here are some of my favourite quotes:

  • Where did the idea come from? I thought, is it possible that maybe we starve a system temporarily for three four or five days and then we go back to a normal diet for months and could it be that that effect lasts months?
  • The importance of metabolic flexibility – I think you one of the things that’s killing all of us, particularly in America is that most people have no metabolic flexibility they’re not able to shift in their mitochondria from burning glucose as a fuel to burning free fatty acids or ketones
  • Fat utilisation mode – The fasting mimicking diet switches the system back into a fat utilization mode. Now, if you go too fast you may slow the metabolism down, so our job was to get it just to the point where the ketogenesis begins.
  • Why five days? So how long do you need in the various cells to get a lot of autophagy [cell repair and cleansing] done? It doesn’t seem to happen a lot in the first two or three days, it’s probably happening starting day four or five.
  • Generating stem cells – the organs shrink during the fasting mimicking diet and then the stem cells are turned on … then we see many different organs beginning to have these stem cells generate new stem cells and generate new cells.
  • How often should we do it? It doesn’t last forever. After three months we see about 40 percent of the effects disappearing, which suggests that by six months you’re getting back to where you started – provided that you you go back to a terrible diet.

How The Fasting Mimicking Diet Works:

You follow the FMD for 5 days. Experts have different ideas about how often you should do it, I’ve seen numbers ranging from from once a month to twice a year, depending on your health and lifestyle goals. It can be hard work and stressful to the body, so Dr Longo recommends about three times a year. The rest of the time you can eat whatever you would on your usual diet.

The basic principles are as follows…

Day 1Days 2 – 4
  • eat around 50% of your normal calorie intake
  • 10% protein, 56% fat and 34% carbs
  • eat around 35-40% of your normal calorie intake
  • 10% protein, 56% fat and 34% carbs
  • Generally you should be aiming for around 800-900 calories over the period (though I’ve had people report good results from 600 to 1,100 calories, so think about what’s realistic for you, especially the first time you try the diet). You can use macro tracking apps to figure out the correct ratios. Remember that it is always best to plan your meals in advance when you are on a macro-based diet or fast.

    The theory behind FMD

    Before we go into detail on the type of foods you should be consuming during these fasting days, it’s important that you understand the theory behind FMD.

    The meals that you eat during these 5 days are designed to nourish your body whilst triggering your body to respond as it would during a fast. In fact, whilst eating on the FMD, your body doesn’t realise that you are taking in food.

    As a result, it should be noted that, while short term fasts like the FMD are much better for the body than long term fasts, it is still best to avoid intense exercise during your fast.  As with any diet, you should also ensure that you are healthy enough to begin with before you put your body through it.

    Fast Mimicking Foods:

    Fast mimicking diet DIY foods - preparation is ket

    A fast mimicking diet DIY approach is definitely possible. As with any meal plan, preparation is the key.

    As a rule, the foods that you eat on this program should be plant-based with a high micronutrient (vitamin and mineral) content.

    One day one, use the few extra calories that you get to your advantage by fuelling the body with healthy fats and complex carbs. Remeber, this is meant to be a nutritious diet, using nutrient-dense, whole foods (and it only lasts five days – so no cheating!)

    If you’re stuck on what fast mimicking foods you should be eating, we’ve included some ideas here.

    Bear in mind that most of these dishes should be homemade so that you are able to track macros precisely.

    Be flexible – Either your lunch or dinner will consist of a lighter meal and most people find that it is easier to make dinner the lighter meal. The options we have included here reflect this but, if this doesn’t work for you, you can definitely swap out the lunch and dinner suggestions.

    FMD Foods for Breakfasts:

    • Avocados and greens powder
    • Mixed berry fruit salad with almonds
    • Blueberry chia seed pudding
    • Lemon, kiwi, banana and strawberry smoothie

    FMD Foods for Lunches:

    • Carrot and walnut soup
    • Sweet potato and kale salad
    • Zucchini noodles with sautéed vegetables
    • Kale risotto

    FMD Foods for Dinner:

    • Olive tapenade and vegetable slices
    • Apple and almond salad
    • Curry with tofu and vegetables

    Getting back to normal

    When you start eating again after the five days are up, ensure that you take it steady and reduce your portion sizes. Your body will not be used to consuming large amounts of food in one go.

    You can also take this chance to slightly reduce your normal portion sizes. Yes, I know I said you can eat normally for the rest of the month, but if you’ve managed to stick with the plan for five days, why not take advantage of the healthy habits and will power changes you’ve made?

    Final Tips:

    • Be healthy – the foods you eat during this period should be nutrient-dense, whole foods and give you plenty of good nutrition, even in small amounts. That said, if you’re concerned you might not be getting enough, it might be a good idea to add a multi-vitamins during your fast.
    • Keep hydrated – As with any diet, remember to drink plenty of water! You can also drink up to 4 unsweetened herbal teas a day and one coffee if you can’t do without the caffeine.
    • Be flexible – If you struggle with sticking to the restricted calories, remember that you can spread them out throughout the day; you don’t have to eat them in three meals.
    • Watch your sugar – If you have a lot of sugar in your diet before starting FMD, it is a good idea to try to wean yourself off before starting the fast so that you do not struggle with cravings.

    Remember to bookmark this Fast Mimicking Diet DIY plan to refer back to in case you get stuck for meal ideas or need some added motivation during your fast!

    1. Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease []
    2. Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease [] [] []
    3. Fasting-mimicking diet cycles reduce neuroinflammation to attenuate cognitive decline in Alzheimer’s models []
    4. Fasting-mimicking diet prevents high-fat diet effect on cardiometabolic risk and lifespan []