Written by Tyler DiGiovanni | BSBM
Fact checked by Sam Coleman, Co-founder
FACT CHECKED
Been reading about fasting and want to dip your toes into the water without jumping all the way in? It might be time to think about trying a fasting-mimicking diet (FMD).
The FMD, a simple yet effective dietary approach, has garnered significant attention for its potential health benefits. Unlike traditional fasting, it doesn't require you to completely cut out food for days on end.
Instead, it allows you to eat small, very specific amounts of food while still reaping the effects of fasting on the body. Let's delve deeper into what an FMD is, its benefits, and how to perform it.
What is a Fasting-Mimicking Diet?
An FMD is a diet designed to fool your body into thinking it is fasting, even though you are still consuming a minimal amount of food.
This diet typically involves consuming very low-calorie, low-protein, and high-fat foods for a short period, usually around five days. The goal is to reap the benefits of fasting without completely abstaining from food.
Dr. Valter Longo and a research team at the University of Southern California developed the concept of FMD.
Their research showed that short-term, periodic fasting could offer many of the same benefits as traditional fasting, such as improved metabolic health, cellular repair, and longevity, while being more sustainable and easier to adhere to than long-term fasting.
Benefits of a Fasting-Mimicking Diet
1. Cellular Autophagy and Regeneration
One of the primary benefits of FMD and fasting in general is its ability to promote cellular autophagy—a process where cells remove damaged components and regenerate. This can lead to improved cell function and longevity.
Studies have shown that FMD can help the body switch into a maintenance mode, allowing for the cleaning out of old cells and the generation of new ones.¹
2. Metabolic Health
FMD can significantly improve metabolic health by reducing blood pressure, improving cholesterol levels, and reducing inflammation.
It has also been shown to reduce insulin-like growth factor 1 (IGF-1), which is associated with aging and cancer risk.²
3. Enhanced Cognitive Function
Some studies suggest that FMD can improve brain function and protect against neurodegenerative diseases such as Alzheimer's.³
This is due to the diet's ability to reduce oxidative inflammation and stress, which are key factors in the development of cognitive decline.⁴
4. Reduced Insulin Resistance and Other Pre-Diabetes Markers
FMD cycles led to a significant reduction in insulin resistance and other markers associated with pre-diabetes, such as fasting glucose and Hemoglobin A1c (HbA1c) levels.
This indicates improved glucose metabolism, which can lower the risk of developing type 2 diabetes.⁵
5. Lower Hepatic Fat as Determined by MRI
Participants showed a significant reduction in hepatic fat fraction, which is a marker for non-alcoholic fatty liver disease (NAFLD). Lowering hepatic fat reduces the risk of liver-related diseases and improves overall liver function.⁶
6. Increased Lymphoid-to-Myeloid Ratio
The lymphoid-to-myeloid ratio is an indicator of immune system age. An increased ratio suggests a rejuvenation of the immune system, making it more effective at responding to infections and reducing the risk of age-related immune dysfunctions.⁷
7. Decreased Biological Age by 2.5 years, Independent of Weight Loss
FMD cycles led to a significant reduction in median biological age by 2.5 years. This was measured using a validated set of blood markers predictive of morbidity and mortality.
The decrease in biological age suggests a slower aging process and a lower risk of age-related diseases.⁸
8. Potential benefits even in relatively healthy individuals
A study showed that even participants who were healthier than the average population experienced positive changes in biomarkers after FMD cycles.⁹
This suggests that FMD can benefit a broad range of individuals by reducing disease risk and potentially extending health span and lifespan.
How to Perform a Fasting-Mimicking Diet
Duration and Frequency
The FMD is typically done for five consecutive days and can be repeated every one to six months, depending on individual health goals and conditions. It is recommended that it be done for at least three consecutive months to see the most benefits.
It is important to consult with a healthcare provider before starting FMD, especially for those with underlying health issues.
Daily Caloric Intake
On the first day, the caloric intake is about 1,100 calories, consisting of 11% plant-based protein (~30g), 46% unsaturated fats (~56g), and 43% complex carbohydrates (~118g).
For the remaining four days, the intake drops to approximately 800 calories per day, with 9% protein (18g), 44% fat (~39g), and 47% carbohydrates (94g).
These are NON-NEGOTIABLE. If you want the results, you need to follow these ratios as closely as possible.
Food Choices
The FMD diet emphasizes plant-based foods that are low in protein but high in healthy fats. Here's a typical breakdown of what you might eat:
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Day 1: A higher calorie day including nuts, seeds, olives, and low-carbohydrate vegetables like kale and broccoli.
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Days 2-5: Reduced calorie intake with similar foods, focusing on soups, vegetable broths, teas, and a small amount of nut bars or olives.
Commercially available FMD kits, such as ProLon, provide pre-packaged meals and snacks designed to meet the diet's nutritional requirements, making it easier to follow without having to measure and prepare foods yourself.
While convenient, they are expensive, and if you plan on doing this more than once, it would be a good idea to be able to design your own FMD. Further below is a sample meal plan.
Hydration
Staying hydrated is crucial. Drink plenty of water, herbal teas, and other non-caloric beverages throughout the fasting-mimicking period. You'll want to be taking down at least a half-gallon of those liquids a day.
Sample Diet for the Fasting Mimicking Diet (FMD)
The Fasting Mimicking Diet (FMD) is designed to mimic the effects of fasting while still providing essential nutrients. It typically spans over 5 days, with a progressive reduction in calorie intake. Here's a sample 5-day plan:
Day 1
- Calories: ~1100 cal
- Macronutrient Breakdown: 11% protein, 46% fat, 43% carbohydrates
Breakfast
- Herbal tea (no sweeteners)
- 1 serving of nut-based energy bar (~250 cal)
Mid-Morning Snack
- Small handful of nuts (almonds or walnuts) (~100 cal)
Lunch
- Vegetable soup (broth-based with low-calorie vegetables like spinach, kale, and mushrooms) (~250 cal)
- 1 slice of whole grain bread (~70 cal)
Afternoon Snack
- 1 small piece of fruit (like an apple or pear) (~80 cal)
Dinner
- Mixed vegetable salad with olive oil and vinegar dressing (leafy greens, tomatoes, cucumbers, and bell peppers) (~200 cal)
- 1 serving of nut-based energy bar (~150 cal)
Before Bed Snack
- Herbal tea (no sweeteners)
Day 2 to Day 5
- Calories: ~800 cal/day
- Macronutrient Breakdown: 9% protein, 44% fat, 47% carbohydrates
Breakfast
- Herbal tea (no sweeteners)
- 1 serving of nut-based energy bar (~250 cal)
Mid-Morning Snack
- Small handful of nuts (~100 cal)
Lunch
- Vegetable soup (~200 cal)
Afternoon Snack
- 1 small piece of fruit (~80 cal)
Dinner
- Mixed vegetable salad with olive oil and vinegar dressing (~150 cal)
Before Bed Snack
- Herbal tea (no sweeteners)
Notes
- Vegetable Soup: Can vary ingredients to include low-calorie vegetables such as zucchini, cauliflower, and celery.
- Nut-Based Energy Bars: These should be low in sugar and high in healthy fats and fiber.
- Portion Sizes: Adjust portion sizes to meet the calorie and macronutrient requirements.
- Herbal Teas: Choose caffeine-free herbal teas to aid hydration and support relaxation.
- Supplements: You may want to consider a multivitamin to make sure you're getting your daily recommended amounts of nutrients while preforming the fast.
Conclusion
The fasting-mimicking diet offers a unique approach to achieving the benefits of fasting without the need to completely abstain from food.
With its potential to promote cellular regeneration, improve metabolic health, enhance cognitive function, and much more, the FMD can be a valuable tool for improving overall health and longevity.
As with any dietary change, especially one with such a drastic reduction in calories, it's essential to consult with your doctor to ensure it's appropriate for your individual needs.
Interested in other types of fasting? Check out our article on the 6 Best Intermittent Fasting Methods and Schedules.
References
- Chung, Ki Wung, and Hae Young Chung. “The Effects of Calorie Restriction on Autophagy: Role on Aging Intervention.” Nutrients, vol. 11, no. 12, 2 Dec. 2019, p. 2923, https://doi.org/10.3390/nu11122923
- Brandhorst, Sebastian, et al. “A Periodic Diet That Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Healthspan.” Cell Metabolism, vol. 22, no. 1, 2015, pp. 86–99, www.ncbi.nlm.nih.gov/pubmed/26094889?dopt=Abstract, https://doi.org/10.1016/j.cmet.2015.05.012.
- Boccardi, Virginia, et al. “The Potential of Fasting-Mimicking Diet as a Preventive and Curative Strategy for Alzheimer’s Disease.” Biomolecules, vol. 13, no. 7, 14 July 2023, p. 1133, www.ncbi.nlm.nih.gov/pmc/articles/PMC10377404/, https://doi.org/10.3390/biom13071133.
- Longo, Valter D, and Satchidananda Panda. “Fasting, Circadian Rhythms, and Time-Restricted Feeding in Healthy Lifespan.” Cell Metabolism, vol. 23, no. 6, 2016, pp. 1048–1059, https://doi.org/10.1016/j.cmet.2016.06.001.
- Brandhorst, Sebastian, et al. “Fasting-Mimicking Diet Causes Hepatic and Blood Markers Changes Indicating Reduced Biological Age and Disease Risk.” Nature Communications, vol. 15, no. 1, 20 Feb. 2024, p. 1309, www.nature.com/articles/s41467-024-45260-9, https://doi.org/10.1038/s41467-024-45260-9.
- Brandhorst, Sebastian, et al. “Fasting-Mimicking Diet Causes Hepatic and Blood Markers Changes Indicating Reduced Biological Age and Disease Risk.” Nature Communications, vol. 15, no. 1, 20 Feb. 2024, p. 1309, www.nature.com/articles/s41467-024-45260-9, https://doi.org/10.1038/s41467-024-45260-9.
- Brandhorst, Sebastian, et al. “Fasting-Mimicking Diet Causes Hepatic and Blood Markers Changes Indicating Reduced Biological Age and Disease Risk.” Nature Communications, vol. 15, no. 1, 20 Feb. 2024, p. 1309, www.nature.com/articles/s41467-024-45260-9, https://doi.org/10.1038/s41467-024-45260-9.
- Brandhorst, Sebastian, et al. “Fasting-Mimicking Diet Causes Hepatic and Blood Markers Changes Indicating Reduced Biological Age and Disease Risk.” Nature Communications, vol. 15, no. 1, 20 Feb. 2024, p. 1309, www.nature.com/articles/s41467-024-45260-9, https://doi.org/10.1038/s41467-024-45260-9.
- Brandhorst, Sebastian, et al. “Fasting-Mimicking Diet Causes Hepatic and Blood Markers Changes Indicating Reduced Biological Age and Disease Risk.” Nature Communications, vol. 15, no. 1, 20 Feb. 2024, p. 1309, www.nature.com/articles/s41467-024-45260-9, https://doi.org/10.1038/s41467-024-45260-9.
Tyler DiGiovanni
Author