Fasting as a Naturopath: Types, Benefits, Safety, and the Fasting Mimicking Diet

Fasting is a central topic in contemporary naturopathy: it has ancient roots but today is one of the most studied strategies to promote well-being and longevity. However, it is not a practice to be improvised nor suitable for everyone. In my naturopathic consultations, I often realize that almost no one respects the nighttime fasting period of at least 12 hours without food—a fundamental aspect and the first, simplest, and most powerful change to propose to those wishing to improve their diet and general health.
Types of Fasting
Nighttime fasting (12 hours):
This involves suspending food intake for about 12 hours, typically from dinner to the next morning’s breakfast. It is the most natural form of fasting, aligned with human circadian rhythms. Respecting this fasting window is associated with numerous metabolic and health benefits.
Intermittent fasting (Time Restricted Feeding):
The most common variations include 16:8 (16 hours fasting, 8 hours feeding), 14:10, or the 5:2 protocol (5 normal days and 2 days of calorie restriction).
Prolonged or alternate-day fasting:
This consists of periods of completefasting for more than 24 hours, or alternating between a fasting day and a normal feeding day.
Special and therapeutic fasts (Fasting Mimicking Diet – FMD):
A studied protocol that simulates the effects of complete fasting by providing controlled calorie restriction for 5 consecutive days. It was developed by Prof. Valter Longo and validated by clinical studies.
Benefits of Fasting
Scientific research has documented numerous benefits of fasting, including:
Improved insulin sensitivity and glycemic control.
Weight loss and reduction of visceral fat, with positive effects on body composition.
Optimization of lipid profile and reduction of blood pressure.
Reduction of systemic inflammation.
Activation of autophagy, a natural process of cellular “cleaning” and regeneration.
However, fasting is not indicated for everyone. Frail elderly individuals may suffer from sarcopenia and metabolic imbalances; people with diabetes or chronic diseases should fast only under close medical supervision.
The 12-Hour Nighttime Fast: Safety and Importance
This type of fast is recognized as the safest and most physiological for the general population. Studies indicate that respecting at least 12 hours of fasting between dinner and breakfast:
Helps regulate weight and glycemic control.
Synchronizes circadian rhythms, improving sleep and overall well-being.
Favors metabolic health by reducing visceral fat, cholesterol, and blood pressure.
Lowers inflammation levels, also decreasing cardiovascular risk.
Unfortunately, due to modern life rhythms, many people eat very late at night, reducing this fast window to less than 12 hours and thereby losing many benefits. Eating late can misalign circadian rhythms, worsen sleep quality, increase blood sugar and inflammation, promote visceral fat accumulation, and increase cardiovascular risk.
For this reason, the first step I suggest in naturopathic practice is to enforce this 12-hour nighttime fast because it is simple to apply, risk-free, and already capable of producing significant changes.
Valter Longo’s Fasting Mimicking Diet (FMD): An Advanced Approach
If you want to go beyond the 12 hours and achieve more significant effects on health and longevity, I recommend considering the Fasting Mimicking Diet developed by Professor Valter Longo.
What is the Fasting Mimicking Diet?
It is a 5-day consecutive dietary regimen with controlled calorie restriction between 800 and 1100 kcal per day, with a precise nutrient distribution: approximately 45% healthy fats, 45% complex carbohydrates, and 10% plant-based proteins. This composition allows activation of the benefits of prolonged fasting without completely abstaining from food.
Benefits of FMD Certified by Research
Reduction of biological age and improvement of numerous longevity markers (studies published in Nature Communications 2024).
Decrease in blood sugar, insulin, IGF-1, and inflammatory markers in both healthy people and those with metabolic syndrome.
Activation of autophagy, cellular repair, and immune regeneration.
In oncology, enhancement of therapy efficacy and potential reduction of side effects.
Proven safety in thousands of subjects under clinical supervision, with mild and transient side effects.
Safety and Limits of the FMD
The FMD should NOT be improvised. It is contraindicated in pregnancy, breastfeeding, minors, people with type 1 diabetes, or severe chronic diseases without medical supervision. It must always be personalized and followed by experienced professionals.
Time to Notice the First Effects of FMD
The first beneficial effects begin to manifest after the initial 5-day cycle, with significant reductions in blood sugar, insulin, IGF-1, and inflammation. More evident effects on visceral fat, fatty liver, and immune regeneration appear after 3-4 monthly cycles. A metabolic adaptation period after each cycle is important to consolidate improvements.
Conclusions
The 12-hour nighttime fast is the first, simplest, and safest step to improve metabolic health and prevent disease. Only those who have consolidated this habit should consider advanced protocols like the Fasting Mimicking Diet by Valter Longo, which offers deeper scientifically documented benefits.
Respecting one’s physiology and proceeding gradually are keys to successfully integrating fasting into life, placing health and lasting well-being at the center.