In recent years, the fasting-mimicking diet (FMD) has garnered significant attention as a dietary approach designed to replicate the physiological effects of fasting while still allowing for the consumption of food. This innovative strategy has been lauded for its potential to promote cellular rejuvenation, support weight loss, and enhance metabolic health.
Understanding the Fasting Mimicking Diet (FMD)
The Fasting Mimicking Diet (FMD) is a 5-day, low-calorie eating plan designed to trick your body into a fasting state while still providing essential nutrients. Developed by researchers at the University of Southern California led by Dr. Valter Longo, the FMD is structured to:
- Restrict calories (500-600 kcal/day)
- Control macronutrient ratios (10% carbs, 15% protein, 75% fats)
- Promote cellular autophagy (the body’s "clean-up" process)
- Enhance metabolic flexibility (switching from glucose to fat burning)
Unlike water fasting, the FMD allows small, nutrient-dense meals, making it more sustainable while still triggering fasting-like benefits.
How Does the FMD Work?
When you fast or drastically reduce calories, your body undergoes several metabolic shifts:
- Glycogen Depletion: After 12-24 hours, stored glucose runs out, forcing the body to burn fat.
- Ketone Production: Fat breakdown releases ketones, an alternative energy source linked to improved brain function and fat loss.
- Autophagy Activation: A cellular "recycling" process that removes damaged cells, potentially slowing aging.
- Reduced Inflammation: Fasting lowers inflammatory markers like CRP, benefiting long-term health.
The FMD mimics these effects without requiring a full fast, making it more accessible for beginners.
Read also: Benefits of the Fasting Mimicking Diet
FMD vs. Other Popular Diets
FMD vs. Intermittent Fasting (IF)
Intermittent fasting (IF) involves cycling between periods of eating and fasting. While both promote metabolic flexibility, key differences include:
- Best for: FMD - Deep cellular detox, anti-aging, metabolic reset. IF - Sustainable fat loss, blood sugar control.
FMD vs. Ketogenic Diet
The ketogenic diet is a high-fat, low-carbohydrate approach that aims to induce a state of ketosis for weight loss and improved metabolic function. While both the FMD and ketogenic diet promote ketosis, they differ in key aspects:
- Best for: FMD - A periodic metabolic "reset." Keto - Ongoing weight loss & neurological benefits.
ProLon Diet: The Commercial FMD Option
The ProLon diet is a commercially available fasting mimicking diet (FMD) program. It offers a pre-packaged meal plan designed to mimic the metabolic effects of fasting while still providing essential nutrients, but they can be expensive ($150-$200 per cycle). A DIY FMD is more affordable and customizable, which we’ll cover next.
What is the ProLon Diet?
Developed by L-Nutra, the ProLon diet is a five-day meal program that provides low-calorie, plant-based meals specifically formulated to induce a fasting-like state in your body. The kit includes individual portions of soups, energy bars, snacks, herbal teas, and supplements, all designed to meet the FMD's macronutrient ratios (low-carb, moderate protein, high healthy fat).
Similarities between ProLon and General FMD:
- Goal: Both the ProLon diet plan and the general FMD aim to mimic the metabolic effects of fasting, potentially promoting cellular rejuvenation, weight loss, and improved health markers.
- Calorie Intake: Both approaches restrict calorie intake to around 500-600 calories per day.
- Macronutrient Ratio: Both emphasize a specific ratio of carbohydrates, proteins, and fats, typically around 10% carbs, 15% protein, and 75% fat.
- Duration: Both the ProLon diet and the general FMD last for five days.
Differences between ProLon and General FMD:
- Convenience: The ProLon diet offers pre-packaged meals, eliminating the need for planning and preparing your own version of FMD meals.
- Cost: The ProLon diet can be significantly more expensive compared to a DIY FMD approach.
- Variety: The ProLon diet provides a set menu, whereas a DIY FMD allows for more flexibility in meal choices within the FMD guidelines.
- Availability of Scientific Research: While research is ongoing for the FMD in general, the specific benefits of the ProLon diet may not be as extensively studied.
Who Should Try the FMD? (And Who Should Avoid It)
Ideal Candidates for the FMD
- Those seeking cellular rejuvenation (anti-aging benefits)
- People with metabolic concerns (prediabetes, insulin resistance)
- Individuals looking for a short-term weight loss jumpstart
- Biohackers interested in autophagy & longevity
Who Should Avoid the FMD?
- Pregnant or breastfeeding women
- People with eating disorders or a history of extreme dieting
- Those with advanced diabetes (unless supervised by a doctor)
- Underweight individuals or those with nutrient deficiencies
Important Considerations Before Starting the FMD
- Consult your doctor: It's crucial to discuss the FMD with your doctor before embarking on this program, especially if you have any pre-existing health conditions, are pregnant, or breastfeeding.
- Not a cure-all: The FMD is a dietary intervention, not a magic bullet for health. It should be combined with a healthy lifestyle for optimal results.
- Potential side effects: The FMD may cause mild side effects like fatigue, headaches, and nausea during the first few days. These typically subside as your body adjusts.
DIY Fasting Mimicking Diet: A Complete 5-Day Meal Plan
There are commercially available FMD kits that provide pre-packaged meals. However, for a more budget-friendly option, you can create your own FMD meal plan. Here's what you need to know:
Read also: Comprehensive Guide to Tea Fasting
Macronutrient Breakdown (Per Day)
The FMD targets a specific ratio of macronutrients:
- Carbs: 50-60g (leafy greens, cruciferous veggies, berries)
- Protein: ~20g (nuts, seeds, tofu, small fish portions)
- Fats: 120-130g (avocado, olive oil, coconut, nuts)
Foods to Eat
- Vegetables: Spinach, kale, broccoli, cauliflower, zucchini
- Healthy Fats: Avocado, olive oil, nuts, seeds
- Proteins: Tofu, tempeh, small portions of fish/chicken
- Beverages: Water, herbal tea, black coffee (no sugar)
Foods to Avoid
- Grains (even whole grains)
- Starchy veggies (potatoes, corn, peas)
- Sugary foods & processed snacks
- High-fat meats (bacon, sausage)
5-Day FMD Meal Plan (500-600 kcal/day)
Day 1
- Breakfast: Green smoothie (spinach, almond milk, chia seeds, ½ cup berries) - 150 kcal
- Lunch: Creamy cauliflower soup (recipe below) - 200 kcal
- Dinner: Stir-fried tofu with sesame oil & veggies - 200 kcal
Day 2
- Breakfast: Chia pudding (almond milk, chia seeds, walnuts) - 180 kcal
- Lunch: Grilled chicken salad (mixed greens, olive oil dressing) - 220 kcal
- Dinner: Roasted Brussels sprouts with garlic & lemon - 150 kcal
Day 3 (Approx. 550 kcal)
- Breakfast: Scrambled Eggs with Mushrooms & Spinach (200 kcal)
- Ingredients: 2 eggs (or ½ cup tofu scramble for vegan option), ½ cup mushrooms, sliced, 1 cup spinach, 1 tsp olive oil, Pinch of turmeric & black pepper
- Instructions: Heat olive oil in a pan. Sauté mushrooms until soft, then add spinach. Scramble eggs (or tofu) with turmeric and pepper.
- Lunch: Lentil Soup with Steamed Broccoli (250 kcal)
- Ingredients: ½ cup cooked lentils, 1 cup vegetable broth, ½ cup broccoli florets, 1 tbsp olive oil, Garlic, cumin, salt to taste
- Instructions: Simmer lentils in broth with spices for 15 mins. Steam broccoli separately. Drizzle with olive oil before serving.
- Dinner: Baked Salmon with Roasted Asparagus (200 kcal)
- Ingredients: 3 oz salmon fillet, ½ cup asparagus, 1 tsp olive oil, Lemon wedge, salt, and pepper
- Instructions: Toss asparagus in olive oil, roast at 400°F for 12 mins. Bake salmon for 10-12 mins with lemon and seasoning.
Day 4 (Approx. 580 kcal)
- Breakfast: Greek Yogurt with Berries & Chia Seeds (180 kcal)
- Ingredients: ½ cup plain Greek yogurt (2% fat), ¼ cup mixed berries, 1 tsp chia seeds, 1 tsp almond butter (optional)
- Instructions: Mix yogurt with berries and chia seeds. Drizzle with almond butter if desired.
- Lunch: Tofu & Veggie Stir-Fry with Almond Oil (200 kcal)
- Ingredients: ½ block firm tofu, cubed, 1 cup mixed veggies (bell peppers, zucchini, bok choy), 1 tbsp almond oil, 1 tsp tamari (low-sodium soy sauce)
- Instructions: Sauté tofu in almond oil until golden. Add veggies and tamari, stir-fry for 5 mins.
- Dinner: Cauliflower Rice with Chicken & Herbs (200 kcal)
- Ingredients: 1 cup riced cauliflower, 2 oz grilled chicken breast (or tempeh for vegan), 1 tsp olive oil, Fresh parsley, lemon juice
- Instructions: Sauté cauliflower rice in olive oil for 5 mins. Top with chicken and herbs.
Day 5 (Approx.)
- Breakfast: Blend all ingredients until smooth.
- Lunch: White Bean & Kale Soup (200 kcal)
- Ingredients: ½ cup white beans, 1 cup kale, chopped, 1 clove garlic, 1 tbsp olive oil, Vegetable broth
- Instructions: Simmer beans, kale, and garlic in broth. Drizzle with olive oil before serving.
- Dinner: Baked Cod with Lemon & Roasted Brussels Sprouts (220 kcal)
- Ingredients: 4 oz cod fillet, ½ cup Brussels sprouts, 1 tsp olive oil, Lemon zest, salt, pepper
- Instructions: Roast Brussels sprouts at 400°F for 15 mins. Bake cod with lemon zest for 10-12 mins.
Key Notes for Success
- Stay hydrated (herbal tea, water, electrolytes).
- Avoid snacking-stick to the 3 meals/day structure.
- Monitor portions (use a food scale if needed).
- Listen to your body-adjust if feeling overly fatigued.
Other Delicious & Easy FMD Recipes
- Creamy Cauliflower Soup (Day 1 Lunch)
- Ingredients: 1 head cauliflower, chopped, 2 tbsp olive oil, 1 onion, diced, 3 cups vegetable broth, ¼ cup almond milk, Salt, pepper, turmeric
- Instructions: Sauté onion in olive oil until soft. Add cauliflower & broth; simmer 20 mins. Blend until smooth, then stir in almond milk & spices.
- Tofu Scramble with Spinach (Day 3 Breakfast)
- Ingredients: ½ block firm tofu, crumbled, 1 tbsp olive oil, 1 cup spinach, ¼ tsp turmeric (for color & anti-inflammatory benefits)
- Instructions: Heat oil in a pan, add tofu, and cook until slightly browned. Stir in spinach until wilted. Season with turmeric, salt, and pepper.
Maximizing Your FMD Results: Best Practices
Before Starting
- Consult a healthcare provider (especially if on medication).
- Prep meals in advance to avoid temptation.
- Hydrate well (herbal teas, electrolytes).
During the FMD
- Stick to the plan-no cheat snacks!
- Manage hunger with herbal tea or broth.
- Rest & recover-avoid intense workouts.
After the FMD
- Gradually reintroduce foods (start with soups & steamed veggies).
- Track how you feel-note energy, digestion, and mental clarity.
Additional Tips:
- Incorporate Flavor: Use herbs, spices, and low-sugar condiments to add flavor to your FMD meals without exceeding your calorie or carbohydrate limits. This can make the experience more enjoyable.
- Support System: Having a supportive network of family or friends can be helpful during the FMD. Let them know about your plans and seek their encouragement to stay on track.
- Explore FMD Resources: Several online resources and cookbooks offer FMD-friendly recipes and information. Utilize these resources to create a delicious and varied meal plan for your FMD cycle.
Potential Benefits & Risks of the FMD
Science-Backed Benefits
- Boosts autophagy (cellular cleanup)
- Improves insulin sensitivity
- Supports weight loss (short-term)
- Reduces inflammation
Possible Side Effects
- Fatigue or headaches (usually temporary)
- Digestive changes (due to low fiber)
- Nutrient gaps (supplement if needed)
A DIY Approach Inspired by Dr. Longo and Dr. Gundry
Inspired by the longevity research of Dr. Valter Longo and Dr. Steven Gundry, it's possible to create a DIY FMD meal plan that leaves room for flexibility. Adapt it to suit your location and the available seasonal produce.
Key Principles:
- Calorie-Restricted: Limit your daily intake to 900 calories or fewer.
- Lectin-Light: Avoid plants with a high lectin content.
- Whole Foods Only: No ultra-processed processed foods are allowed.
- Sugar-Free: Exclude sugars, including most fruits.
- Nutrition-Dense: Adhere to a nutritarian approach, focusing on nutrient-rich foods that are low in calories. Don’t deprive yourself of essential nutrients.
Transitioning After the FMD:
After the five days, transition with a day of plant-based, normal-calorie diet. Include complex carbs like sweet potatoes, beans, or lectin-free grains.
Important Note:
While this plan is generally considered low in histamines, it’s essential to note that some lists may not categorize beans as such. However, many foods in this cleanse possess anti-histamine properties.
Sourcing Produce:
For optimal nutrition, prioritize sourcing local, organic, in-season produce, and try to eat a mix of both raw and cooked vegetables. The aim isn’t perfection but making the most of what’s readily available.
Read also: Drinking Diet Coke Before Testing
Beans and Legumes:
In this diet plan, beans and legumes will be a part of every meal. It’s essential to soak and pressure-cook them to reduce harmful lectin levels. Lentils are rinsed thoroughly and pressure-cooked for 15 minutes, without soaking. But be careful, some lentils can go to mush if overcooked, so is better to stick to green lentils, also called French lentils, as they hold their shape well. Chickpeas, on the other hand, should be soaked overnight, rinsed multiple times, and pressure-cooked for approximately 24 minutes. To ensure optimal cooking, I don’t add salt to the cooking water.
For a hassle-free experience with the DIY fasting-mimicking diet, prepare beans beforehand and freeze them. This allows you to directly use them for stews or other dishes. Organic canned beans that have been soaked and pressure cooked are also an option.
Bean stewing is straightforward. Begin with a small amount of extra virgin olive oil (or an oil of your choice), sauté onions until they’re aromatic, add garlic and beans, and pour a bit of water to prevent sticking. Should you opt for other greens, like kale, add them towards the end of the cooking process. Fresh herbs like parsley and cilantro enhance the flavor profile and the nutrition of the dish.
Seasoning and Flavor Enhancement:
During the cleanse, embrace simplicity, using Herbs de Provence, complemented by salt and pepper. Enhance flavors using fresh herbs like cilantro, parsley, dill, rosemary, thyme, oregano, and basil. Speaking of seasonings, adjust salt to your palate. Remember, salt is vital, especially when cutting out processed foods laden with it. Himalayan pink salt is a good option. Alternatively, introduce seaweeds into your meals for a burst of umami and a natural source of iodine.
Portion Control and Calorie Awareness:
While counting calories is not typically recommended, when adhering to a calorie-restricted meal plan, it’s unavoidable. It’s easy to underestimate our caloric intake. Thus, careful portion control is crucial to maintaining a daily intake of under 900 calories, especially when it came to oils, nuts, beans, and starchy vegetables. This plan recommends a maximum daily intake of 8oz (1 cup) of beans or legumes. To make the experience more palatable, chickpeas and lentils can be incorporated in nearly every meal, but keep it to a maximum of 1/2 cup per meal.
Oils are another high-caloric food that needs monitoring. The choice of oils for this plan are extra virgin olive oil, coconut oil, and sesame oil.
While most vegetables and greens have a low-calorie content, and you shouldn’t stress about how much you are eating, starchy vegetables like sweet potatoes require monitored portions. 100 grams of cooked sweet potato, which is a little less than 1/2 cup, has 86 calories. Sweet potatoes should be cooked, cooled, and then reheated for enhanced nutritional benefits. This process increases resistant starch and ensures slower sugar absorption.
Meal Frequency:
There are different ways to split the allowed food/calories throughout the day, but two meals a day: lunch and early dinner, is a good schedule. The first meal can be around noon, and dinner no later than 6 pm. Sometimes snacks in between and coffee in the morning are okay.
Sample Meal Ideas:
- Sauté leeks, onions, and ginger in a small amount of oil until translucent. Season with salt, pepper, and Herbs de Provence. Garnish with hemp seeds and a light drizzle of olive or hemp seed oil.
- To make hummus, mix in a blender: 1/2 cup chickpeas per serving, 1/2 teaspoon tahini per serving, 1 teaspoon extra virgin olive oil per serving, lemon juice, salt. Optionally you can add cumin and garlic. Sprinkle with some toasted nigella sativa seeds. Accompany with a green salad, olives, a quarter of an avocado, and an optional fig.
- Pair with boiled Brussels sprouts and a beetroot salad mixed with horseradish, olive oil, and apple cider vinegar.
- Serve warmed, pre-cooked sweet potato with a cabbage salad, hummus, raw vegetables, and a green salad. Adjust hummus and sweet potato quantities as desired to meet the required calories.
- Combine plain pressure-cooked lentils, raw cauliflower, steamed broccoli, and olives on a bed of arugula. Dress with EVOO and seasonings. You can cook the cauliflower if you prefer.
Plant-Based Soups:
Plant-based soups are nutrient-rich, low in calories, easy to prepare, and can replace any of the meals above. They are also great for people struggling to digest raw or minimally cooked vegetables.
Sauté a mix of finely chopped vegetables, such as onions, leeks, carrots, parsnips, celeriac, celery, and fennel, in EVOO until softened. Incorporate red bell pepper for flavor if you can eat peppers. Add herbs and seasonings like rosemary, thyme, bay leaves, salt, and pepper, followed by cooked beans of your choice, and water to cover them. Simmer for about 10-15 minutes, then add chopped leafy greens, and cook for another 5 minutes.
Low-Calorie Brownies:
Combine all the dry ingredients in a bowl: 31g of flax meal, 21g of hemp seeds, 10g of cacao powder, 20g of plantain flour, 10g of psyllium husk, 60g of tigernut flour, 30g of chopped walnuts, a pinch of salt. Blend the wet ingredients: 60g sweet potato, 20ml coconut milk, 20ml water (add more if necessary). Gently combine the wet and dry mixtures until they form a cohesive, slightly sticky dough. Roll the dough between two pieces of parchment paper to about 1/4 inch thickness, or slightly thinner. Then, divide it into approximately 16 equal parts.
Hydration and Supplements:
Hydration is always vital, but it becomes even more critical during a regimen like the FMD. While coffee can be included, this period can serve as an excellent opportunity for those considering a caffeine break. Matcha and green tea are acceptable, but if you’re thinking of abstaining from caffeine entirely, herbal teas are a fantastic alternative. As for supplements, feel free to stick to your regular regimen.
Personal Experiences and Insights:
Embarking on the 5-day fasting-mimicking diet meal plan can be an enlightening experience. The most challenging part may be the calorie counting, which can feel quite foreign and time-consuming. Although the type of food included in this plan mirrors a regular diet, it may be necessary to incorporate more fats, more complex carbs, and animal protein into daily meals.
Since intermittent fasting is practiced regularly, this may not be too hard, but you may be excited to reintroduce some protein and carbs. You may manage to shed some weight, an expected outcome given the severe calorie restriction.
While weight loss is a noticeable result, the goal of the 5-day fasting-mimicking diet should not be solely weight loss. Although it’s challenging to quantify the benefits of fasting, a surge in energy levels and mental clarity may be felt. Hunger may not be an issue during the plan, but you may feel a strong urge to reintroduce carbs.
It’s important to remember that each individual’s experience will vary.
Fast-Mimicking Diet Recipes
When it comes to the fast-mimicking diet, the focus is on consuming low-calorie, nutrient-dense foods that will help you stay full and satisfied throughout the day. Some good foods include vegetables, fruits, nuts, and seeds.
One of the best things about the fast-mimicking diet is that you don’t have to stick to a specific set of foods. Some great choices for vegetables include leafy greens, carrots, broccoli, and sweet potatoes. And when it comes to nuts and seeds options like almonds, walnuts, pumpkin seeds, and chia seeds are all great choices.
Additional Recipe Ideas
- Spinach and feta omelet: Crack two eggs into a bowl and whisk them together with a handful of spinach and crumbled feta cheese. Then put some olive oil into a nonstick pan and pour the mixture into that.
- Smoothie: Take One Cup of any type of frozen berries that you like and mix that in with half a banana, half a cup of almond milk, and a handful of spinach.
- Turkey lettuce wraps: Take lettuce leaves and play sliced Turkey, cucumber, and tomato inside.
- Greek salad: Toss together whatever mixed greens you like, cucumber, tomato, feta cheese, and olives.
- Grilled chicken with zucchini noodles: Take a chicken breast and marinate it in olive oil, lemon juice, and herbs of your choice.
Remember that fast mimicking is all about incorporating healthy, nutrient-dense foods into your meals.