Eating Less Often: How Fasting Paves the Way to a Longer Life

Explore the transformative health benefits of eating less often. Uncover how fasting boosts autophagy, enhances cellular repair, and extends lifespan. Learn about the science of sirtuins, mTOR, and AMPK, and discover practical fasting methods and tips for a healthier, longer life

Eating less often is a powerful key to living longer. This isn't just about eating fewer calories; it's about the time when you're not eating at all. When we don't eat for a while, our bodies start repairing and cleaning our cells. This process, called autophagy, helps fight aging by getting rid of damaged parts in our cells. Even if you're not losing weight, fasting itself triggers these healthy changes. Research shows that it's not the size of your body but how often you eat that matters more for a longer life.

Recent studies have shed light on the profound benefits of fasting, not only for weight management but also for cellular repair and disease management. In a recent study, participants observed fasting from dawn to sunset for four weeks, which led to improved blood pressure, reduced body mass index (BMI), decreased waist circumference, and notably, the upregulation of DNA repair proteins. This finding is significant as it echoes results previously observed in model organisms, indicating a fundamental biological response to fasting that extends beyond mere weight loss.

Fasting is not about starving or extreme dieting. It's about choosing when to eat and when not to. This timing can naturally lead to eating less, but the real benefit comes from letting our bodies enter a state where they can focus on self-repair. By eating less often, we give our bodies a chance to strengthen and protect themselves against aging. So, in a way, eating less often could be one of the best things you can do for a longer, healthier life.

A mechanism as ancient as life itself: what yeast teaches us about longevity

The most reliable way to extend the lifespan of any animal (from a yeast cell to a pet Labrador) is to restrict its calories.

Researchers found that when the glucose intake of yeast – their primary source of nutrition – is limited, there's a remarkable increase in their lifespan. Under standard conditions, yeast cells divide approximately 25 times. However, when their glucose supply is substantially reduced, these cells can exceed 30 divisions. This increase in lifespan isn't simply due to the reduction of food intake. By cutting down on calories, the yeast cells were able to change their metabolism to a more efficient energy-producing process, which in turn helped them live longer. This represents a fundamental biological response to the scarcity of resources, a survival strategy deeply embedded in the genetic makeup of living organisms.

The role of sirtuins: the guardians of DNA

Guardians of the DNA

The key players in this response are genes known as sirtuins, which get activated in low-energy environments. These genes respond to various types of stress, illustrating a biological principle where a certain amount of stress actually makes an organism stronger. In the case of yeast, reduced glucose levels triggered these sirtuins, enhancing DNA repair and the stabilization of genetic information.

When an organism undergoes fasting or calorie restriction, sirtuins play a crucial role in extending its lifespan. These remarkable genes are tasked with safeguarding DNA and ensuring that genes remain active when needed. The mechanism underlying their increased activity during caloric restriction involves a fascinating series of events. Scientists discovered that low energy levels activate a specific gene, known as PNC1 in yeast or NAMPT in humans. This gene is responsible for producing a molecule called NAD (nicotinamide adenine dinucleotide), which serves as fuel for sirtuins.

During periods of fasting or low glucose levels, the organism activates genes like PNC1/NAMPT, resulting in an increased production of NAD. This small molecule is essential for sirtuins to function effectively. With an ample supply of NAD, sirtuins go to work by repairing DNA damage and stabilizing the epigenome, the chemical modifications that regulate gene expression. This process ultimately contributes to the extension of an organism's lifespan. The revelation that fasting triggers the activation of sirtuins through NAD production has paved the way for the development of NAD boosters, compounds like NR and NMN, which have garnered significant attention in recent years for their potential to enhance longevity and health. Low glucose levels activate the natural defense mechanisms that have evolved over billions of years to protect the organism.

Exploring the role of mTOR and AMPK in aging and health

Fasting also influences two other key longevity genes: mTOR (mammalian target of rapamycin) and AMPK (AMP-activated protein kinase). These genes play a pivotal role in cellular health and aging.

mTOR & autophagy

The protein complex mTOR is sensitive to amino acids, especially those from protein-rich foods. When we consume protein, mTOR is activated, stimulating cellular growth and muscle development. However, this isn't necessarily conducive to longevity. Research indicates that reducing mTOR activity can extend lifespan, primarily by triggering autophagy, where cells recycle old proteins for new, healthier ones. This process is essential for cellular health and longevity. Studies on flies and mice have shown that inhibiting mTOR and stimulating autophagy can significantly increase lifespan, underscoring the complex's importance in the aging process.

AMPK: the energy regulator influenced by fasting

AMPK stands for AMP-activated protein kinase, an enzyme that responds to low energy levels, such as those experienced during fasting. Increased AMPK levels lead to several beneficial outcomes, including the enhancement of mitochondrial production. Mitochondria are vital for energy production and metabolism, and their decline is a hallmark of aging. Activating AMPK through fasting helps maintain mitochondrial health, contributing to increased energy and possibly extending longevity.

It's crucial to acknowledge that much of our understanding comes from animal studies. Human research in this area is limited and often involves smaller sample sizes. Nonetheless, the evidence we have suggests that mTOR and AMPK are influential in human health as well. While the field of longevity research is still evolving, the current data suggest that managing mTOR and AMPK activity through fasting can be beneficial for health and longevity.

In conclusion, fasting emerges not just as a dietary choice but as a potent influencer of key longevity pathways. The suppression of mTOR and the activation of AMPK highlight a fascinating interplay between diet, cellular health, and aging. As we continue to unravel the intricate mechanisms of aging, fasting stands as a promising avenue for enhancing health and potentially extending lifespan.

For how long must I fast to trigger autophagy?

The onset of autophagy from fasting varies among individuals, and several factors including age, metabolic health, and previous dietary habits can influence this. Generally, autophagy is thought to begin under conditions of nutrient deprivation, and the timelines often cited in scientific literature are as follows:

  1. Short-term Fasting (12-16 hours): Initial stages of autophagy may begin in this window, particularly in those who are already adapted to a fasting lifestyle or ketogenic diet. However, this is typically considered a mild induction.
  2. Intermediate Fasting (16-24 hours): Many sources suggest that more significant autophagy starts around 16-24 hours of fasting. This is when the body significantly ramps up breakdown processes to compensate for the lack of external nutrients.
  3. Extended Fasting (24-48 hours and beyond): Peak levels of autophagy are often reported to occur somewhere between 24 to 48 hours of fasting. This is when cells are thought to undergo the most intensive cleanup and recycling processes.

It's important to note that the scientific understanding of autophagy is still evolving, and these timeframes are based on current research which is subject to change as more is learned. Additionally, fasting, especially for longer periods, should be approached cautiously and ideally under medical supervision, particularly for individuals with health conditions or those taking medications.

How and where should I start?

There is a lot of information out there about how to start fasting. You should let your body get accustomed to the sensation first. Starting with skipping one meal and gradually extending your fasting period can help your body adapt more comfortably. This gradual approach is especially beneficial for liver adaptation, reducing the feeling of hunger over time. Here are some of the most popular fasting routines.

1. Intermittent Fasting (IF): Beyond the 24-Hour Mark: 

Intermittent fasting extends beyond a day, with some individuals practicing it for up to a week. This regimen activates autophagy, a cellular cleansing process, particularly strongly after three days. While IF can be highly effective, it's important not to overdo it — extended fasting periods should not exceed a week to prevent muscle loss.

2. Time-Restricted Feeding: Fitting Fasting into Daily Life

Time-restricted feeding involves fasting for at least 16 hours with an 8-hour window for eating. One common practice is to incorporate one meal a day (OMAD). This will ensure fasting for over 20 hours daily, eating only at dinner (for example). This method stabilizes blood glucose levels throughout the day and can help reduce hunger and improve mental clarity.

3. Fasting-Mimicking Diet: A Balanced Approach

Developed by Valter Longo, the fasting-mimicking diet is a unique blend of fasting and eating. It aims to lower mTOR activity and reduce intake of branched-chain amino acids. This diet tricks the body into a fasting state, even though you're still consuming food, albeit in a controlled manner. It's a suitable option for those seeking the benefits of fasting without strict adherence to no-food periods.

Tips to make fasting easier
  • Staying Hydrated and Satiated: Managing hunger is crucial in any fasting regimen. Staying hydrated with fluids like water, tea, and coffee, and snacking on protein-rich foods like nuts, can help curb hunger. It's a simple yet effective strategy to make fasting more manageable.
  • Continuous Glucose Monitoring: Understanding how different foods affect your blood sugar is key to optimizing your diet. Continuous glucose monitoring provides real-time feedback, allowing for dietary adjustments based on how your body responds to various foods.
  • Ensuring Adequate Nutrition: It's essential to maintain adequate nutrition during your eating windows. Supplements like Athletic Greens can help fill any nutritional gaps, ensuring that your body gets what it needs to function optimally.
  • Reducing Sugar Intake: High-sugar foods can be detrimental to health, contributing to diseases like fatty liver and diabetes. Reducing sugar intake, especially from high-fructose sources, is crucial in any fasting or dietary regimen.

Fasting is not a one-size-fits-all solution. It requires personalization, attention to your body's responses, and a commitment to adequate nutrition. By exploring these varied fasting methods and finding what works best for you, you can embark on a journey to better health and wellness. Remember, it's always advisable to consult with a healthcare professional before starting any new diet or fasting regimen.

more insights...