If you’ve ever been curious about fasting but not quite ready to give up food entirely, this diet is a superb middle ground. However, like any other diet, it comes with several risks and perks.
You can get all the benefits of fasting without actually having to skip meals, but the secret is the cycle lasts five days. This is an incredibly interesting approach to dieting, so here is everything you need to know about a fasting-mimicking diet in one place!
What Is a Fasting Mimicking Diet?
The fast-mimicking diet (FMD) is a very specific dietary regimen designed to provide all the benefits of fasting while still allowing some caloric intake. Dr. Valter Longo and his team developed it at the University of Southern California. The diet is typically low in calories, sugars, and proteins but high in healthy fats, and there is a very good reason behind that.
The main goal is to mimic the body’s physiological response to fasting, including cellular repair, reduced inflammation, and improved metabolic health, but without completely abstaining from food. Of course, due to these particular rules, you should consult with your health specialist before starting anything!
Key Features of the Fasting Mimicking Diet
Duration: The diet usually lasts for five consecutive days each month, but the frequency varies depending on your goals and health status. Based on your needs, you can follow it less frequently, such as every few months or so. After completing the five-day cycle, you just return to your regular diet, allowing your body to recover and avoid nutrient deficiencies.
Caloric Intake and Structure: Split this diet into two parts: day one and days 2-5. Consider the first day a “transition” into the fasting state and consume about 1,100-1,200 calories a day. This is still significantly lower than a typical daily intake but not as low as in the following days. Don’t skip this stage, as it helps the body ease into the fasting-like state.
On 2-5 days, reduce caloric intake to around 700-800 calories per day. This is extremely low, though, but the specific macronutrient balance will ensure the body functions normally while being in a fasting-mimicking mode. It triggers the physiological responses tied to fasting but still allows you to eat.
Macronutrient Composition
Low Protein (9-10%): Minimize protein intake to cut down levels of the insulin-like growth factor 1 (IGF-1) hormone. IGF-1 hormone goes hand in hand with aging and cancer development, so lowering protein consumption promotes cellular protection and regeneration processes.
Low Carbohydrates (34-47%): Limit carbs intake, particularly sugars and refined ones, to avoid insulin spikes. This will keep your body in a state similar to fasting. Focus on carbohydrates that come from vegetables and other low-glycemic sources.
High Fat (44-56%): Healthy fats make up the majority of the caloric intake, providing sustained energy while keeping insulin levels low. Choose ingredients like nuts, seeds, olives, and olive oil. The high fat content will induce ketosis, the state where your organism starts to burn fat for fuel, mimicking the effects of fasting.
What to Eat on FMD?
- Non-Starchy Vegetables: Opt for low-calorie, non-starchy veggies like kale, spinach, broccoli, cauliflower, zucchini, and bell peppers. These are staples because of their nutrient density and high fiber content while being low in carbs.
- Soups: Vegetable-based soups are the usual meal on the FMD. Make them with ingredients like tomatoes, celery, carrots, and spinach, boosting flavors with herbs and spices.
- Olives and Olive Oil: They are rich in healthy monounsaturated fats, and olive oil is the key component of this diet.
- Nuts and Seeds: Almonds, walnuts, chia seeds, and flax seeds are peculiarly high in healthy fats and low in carbs, making them ideal for FMD.
- Avocado: Great source of healthy fats, but in moderation.
- Herbal Teas: Unsweetened herbal teas are amazing for the diet, as they provide hydration without calories and sugars.
- Small Amount of Fruits: Opt for low-sugar fruits, like berries, but consume them minimally.
- Protein Sources: You will get enough protein from nuts and seeds or small amounts of legumes.
What to Avoid on FMD?
- Animal Proteins: all meat, eggs, and diary
- Grains and Starches: bread, rice, pasta, potatoes, corn
- Sugar: desserts, sweets, beverages
- Processed Foods: all pre-packed foods, fast food, and convenience food
- Refined Oils: soybean, corn, or canola oil
- Alcohol and Caffeine Drinks
- Starchy Vegetables: sweet potatoes, pumpkins, root vegetables
- High-Sugar Fruits: bananas, mangoes, grapes
Benefits of a Fasting Mimicking Diet
Cellular Regeneration: The secret power of FMD is triggering autophagy – a process where the body cleans out damaged cells and regenerates new ones. This is actually a chief benefit of fasting, leading to improved cellular health and longevity. During the fasting period, the body conserves energy by slowing the production of new cells.
But, when normal eating resumes, stem cell production skyrockets, promoting regeneration and repair.
Metabolic Health: After a few cycles of the diet, participants confirmed improved insulin sensitivity, lower blood glucose levels, and reduced inflammation. What’s more, the diet lowers levels of total cholesterol, LDL (bad) cholesterol, and triglycerides. All of these perks mean only one thing – a lower risk of metabolic conditions like diabetes and cardiovascular troubles.
Weight Loss: The FMD boosts fat loss while preserving lean muscle mass. This stands because it encourages the body to burn fat stores for energy due to its low-calorie, high-fat nature. At the same time, the protein restriction is not severe enough to provoke significant muscle degradation.
Because of the combination of low caloric intake and ketosis, you will inevitably lose weight, especially in the abdominal area. This is incredibly important because visceral fat means a higher risk of metabolic diseases.
Longevity and Healthy Aging: Some studies suggest that this diet can actually extend lifespan and lessen the risk of age-related diseases by lowering oxidative stress and promoting a more favorable metabolic profile.
The combination of improved metabolic health, reduced inflammation, enhanced cellular repair, and less oxidative stress helps to slow the aging process. In the end, this FMD is a great tool for extending the health span – the period of life spent in good health.
Improved Immune Function: This diet is particularly beneficial for golden-agers whose immune systems tend to diminish with age. It promotes the regeneration of immune cells, propping up immune function.
Cons of a Fasting Mimicking Diet
Hunger and Discomfort: Despite allowing some food, this diet is still very low in calories. This usually ends up in persistent hunger, especially in the first few days. This can make it tricky to stick to the diet, especially in the long run.
What’s more, it is not rare at all to experience side effects such as dizziness, headaches, fatigue, and irritability due to the significant caloric restriction and changes in metabolic state.
Potential Nutrient Deficiencies: Because of the restricted nature of the diet, there is always a risk you won’t get enough essential nutrients during those five days of “fasting.” Of course, a few cycles can’t harm you, but over time, if you repeat the diet frequently without proper nutrition during non-fasting days, it can result in deficiencies.
Not Suitable for Everyone: Keep in mind that this diet is not suitable for everybody. People with certain medical conditions – diabetes, eating disorders, or underweight individuals should skip it. Of course, this stands for pregnant and breastfeeding women, too, due to increased nutritional needs during these periods.
Last but not least, people who are highly active or athletes will probably find this diet particularly challenging as it is difficult to preserve energy for performance.
Psychological Impact: As you already know, this diet is highly restrictive, so it can trigger different eating disorders. It might lead to an unhealthy focus on food, counting calories, or anxiety about eating. Due to FMD being quite specific, it can be super challenging to follow in social situations, provoking isolation in social activities involving food.
Yo-Yo Effect: It is not rare for people to regain all their lost weight after returning to their normal diet, especially if they didn’t adopt healthier eating habits during non-fasting periods. Unfortunately, this can result in a frustrating and counterproductive cycle of weight loss and gain.
Fasting Mimicking Diet Plan Examples
Day 1
Breakfast: unsweetened herbal tea + 10 almonds + half an avocado
Lunch: vegetable soup (tomatoes, zucchini, spinach, and celery) + 1 tbsp olive oil
Snack: 5 olives + 1 small cucumber
Dinner: mixed greens salad with 1 tbsp olive oil and lemon juice + ½ cup steamed broccoli + ½ vegetable broth
Day 2
Breakfast: unsweetened herbal tea + 5 walnuts
Lunch: vegetable soup + 1 tbsp olive oil
Snack: 5 olives + 1 small carrot
Dinner: 1 cup steamed kale with lemon juice + 1 tbsp olive oil + ½ cup vegetable broth
Day 3
Breakfast: unsweetened herbal tea + 10 almonds + 1 small apple
Lunch: vegetable soup + 1 tbsp olive oil
Snack: 5 olives + ½ cucumber
Dinner: 1 cup steamed broccoli + 1 tbsp olive oil + ½ vegetable broth
Day 4
Breakfast: unsweetened herbal tea + 1 tbsp chia seeds soaked in water
Lunch: vegetable soup + 1 tbsp olive oil
Snack: 5 walnuts + 1 small carrot
Dinner: mixed greens salad with 1 tbsp olive oil and lemon juice + ½ vegetable broth
Day 5
Breakfast: unsweetened herbal tea + 10 almonds
Lunch: vegetable soup + 1 tbsp olive oil
Snack: 5 olives + 1 small cucumber
Dinner: 1 cup steamed kale with lemon juice + 1 tbsp olive oil + ½ cup vegetable broth
image sources
- CrossFit myths: Photo courtesy of CrossFit Inc.
