Fasting has gained widespread attention in the health and wellness space as a powerful tool for metabolic health, longevity, and even disease prevention. Whether it’s a simple overnight fast or a more extended multi-day fast, adopting a fasting practice can offer significant benefits—if done correctly and tailored to the individual.
Let’s explore the benefits of fasting, why some people struggle with it, and how genetics and metabolic factors, play a role in determining the right fasting strategy for you.
The Benefits of Short-Term Fasting (12-24 Hours)
Short-term fasting, such as intermittent fasting (IF), typically involves fasting windows of 12-24 hours, often practiced as 16:8 fasting (fasting for 16 hours and eating within an 8-hour window). This type of fasting is an accessible way to tap into several health benefits, including:
- Metabolic Health: Fasting for 12+ hours allows insulin levels to drop, supporting better blood sugar regulation and reducing the risk of insulin resistance.
- Cellular Repair: A short fast can trigger mild autophagy, a process where the body removes damaged cells and regenerates new ones—which benefits longevity and reduces inflammation.
- Mental Clarity: With consistent intermittent fasting over time, many people report improved focus and cognitive function as the brain becomes more efficient at switching to ketones for energy instead of glucose. Initially, the body relies on stored glycogen, but with regular fasting, metabolic flexibility improves, making this transition smoother.
- Weight Management: Intermittent fasting naturally reduces calorie intake while promoting fat burning, supporting healthy weight management.
While short fasts are generally well-tolerated, it’s important to stay hydrated and ensure adequate nutrient intake during eating windows.
The Benefits of Prolonged Fasting (48+ Hours)
Extended fasts, which can last 48 hours or more, provide deeper physiological benefits beyond those of intermittent fasting. These longer periods of fasting have been shown to:
- Enhance Autophagy: Prolonged fasting triggers a more significant level of cellular cleanup and regeneration, which may help with aging and disease prevention.
- Reset Metabolism: Longer fasts can help break through metabolic plateaus and enhance insulin sensitivity.
- Support Cancer Prevention: Emerging research suggests fasting may support cancer treatments by slowing tumor growth and enhancing the body’s resilience.
- Reduce Inflammation: Extended fasts have been linked to lower levels of inflammatory markers, supporting conditions such as autoimmune diseases and chronic pain.
While prolonged fasting can be beneficial, it requires careful planning and medical guidance to avoid potential risks such as electrolyte imbalances and nutrient deficiencies.
Why Some People Struggle with Fasting
Fasting isn’t a one-size-fits-all solution. Some individuals may experience dizziness, irritability, or extreme hunger, which could be related to underlying metabolic or genetic factors. Common reasons fasting might feel challenging include:
- Blood Sugar Imbalances: Insulin resistance or reactive hypoglycemia can cause energy crashes and intense hunger during fasting periods.
- Chronic Stress: Chronic stress can lead to fluctuations in cortisol, making fasting more challenging.
- Nutrient Deficiencies: Deficiencies in key nutrients like magnesium, B vitamins, and electrolytes can make fasting feel harder than it should.
If fasting feels unsustainable, working with a healthcare provider to address underlying concerns before attempting longer fasts is crucial.
Genetic and Metabolic Factors That Influence Fasting Tolerance
- SLC (Solute Carrier) Genes: These genes are responsible for nutrient transport across cell membranes. Variants in SLC genes can affect how well your cells absorb glucose and amino acids, potentially influencing energy levels during fasting.
- PPAR-Alpha (Peroxisome Proliferator-Activated Receptor Alpha): This gene regulates fat metabolism and ketone production. Individuals with lower PPAR-alpha activity may have difficulty efficiently switching to fat-burning mode during fasting.
- APOE4 Gene: Those with the APOE4 variant may have a harder time metabolizing fats and could benefit from modified fasting approaches with strategic nutrient intake.
- Aldehyde Dehydrogenase (ALDH2): Variations in this gene can affect how the body processes fasting byproducts, such as aldehydes, which can contribute to fatigue and sluggishness.
- MTOR Pathway Activation: Genetic variations in the mTOR pathway, which regulates cellular growth and repair, can determine how well fasting-induced autophagy occurs.
Genetic testing, offered at MindStream, can help uncover how your body responds to fasting and guide a personalized fasting plan.
How to Get Started with Fasting Safely
- Start Slowly: Begin with a 12-hour overnight fast and gradually increase fasting windows as your body adapts.
- Stay Hydrated: Drink plenty of water.
- Focus on Nutrient-Dense Meals: Prioritize whole, nutrient-rich foods when breaking your fast to sustain energy and metabolism.
- Listen to Your Body: Pay attention to how you feel during fasting periods and adjust accordingly.
- Consider Testing: Genetic and metabolic testing can provide insights into how your body responds to fasting and help tailor an approach that works best for you.
MindStream Can Help You Personalize Your Fasting Journey
Our team at MindStream Integrative Medicine understands that every individual and their health journey is unique. Our team offers comprehensive genetic testing, metabolic assessments, and expert support to help you design a fasting plan that aligns with your health goals and unique physiology.
Using tools like the 3×4 Genetics Panel, we can assess your genetic predisposition to metabolic challenges, nutrient deficiencies, and fasting tolerance.
To schedule an appointment, call 615.541.9933 or book online.
Disclaimer: This information is for general knowledge and educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns. If you’re considering fasting, please discuss it with your doctor to weigh the potential risks and benefits. They can provide you with the most up-to-date information and guidance based on your individual situation.
Alyssa Kalams, MSN, AGNP-C, PN1
Nurse Practitioner + Nutrition Coach
As a nurse practitioner, Alyssa employs a holistic approach to patient care, integrating nutrition and lifestyle strategies to promote overall well-being. She has a special interest in skin health and has completed additional training in integrative dermatology through LearnSkin.
Learn more about Alyssa and the MindStream team.