Expert Q&A

Do you prefer to do prolonged fasting (to induce autophagy) in the summer or winter and the role of cortisol and stress hormones

Understanding Prolonged Fasting and Autophagy

I often guide beginners over 45 who have tried every diet without success. Prolonged fasting, typically 24-72 hours, triggers autophagy — your body's cellular cleanup process that removes damaged proteins and improves metabolic health. This is particularly valuable for those battling hormonal changes, diabetes, and stubborn weight. In my methodology outlined in my book, I emphasize pairing fasting with realistic lifestyle shifts rather than extreme protocols that lead to burnout.

For middle-income adults juggling work and joint pain, autophagy can reduce inflammation that worsens knee and hip discomfort, making movement feel less impossible. Studies show autophagy peaks around 24-48 hours, aiding insulin sensitivity — crucial when managing blood pressure and blood sugar alongside weight loss.

Summer vs Winter: Which Season Works Better?

I recommend prolonged fasting in winter for most of my clients in the United States. Colder months naturally align with lower calorie needs and reduced social eating pressure. In summer, heat increases dehydration risk during fasts, and higher outdoor activity can spike hunger. Winter's shorter days also support better melatonin regulation, which complements fasting's circadian benefits.

However, individual factors matter. If summer means less work stress for you, it could be ideal. My approach avoids rigid rules — we track how your body responds using simple metrics like energy levels and joint comfort instead of complex plans that overwhelm beginners.

The Critical Role of Cortisol and Stress Hormones

Cortisol, your primary stress hormone, rises during fasting and can hinder weight loss if chronically elevated. This is a common pitfall for those embarrassed by obesity or frustrated by past diet failures. In winter, seasonal affective disorder may naturally elevate cortisol, so I teach stress-reduction techniques like short daily walks (even with joint pain) and proper hydration.

Summer heat can also stress the body, raising cortisol and counteracting autophagy gains. My book details how to time fasts around low-stress windows — perhaps a 36-hour fast mid-week when schedules allow. For those with diabetes or blood pressure concerns, monitoring these hormones through basic bloodwork helps prevent counterproductive spikes. Beginners often see better fat loss when cortisol stays balanced, as unchecked stress promotes belly fat storage despite fasting.

Practical Tips Tailored for Your Life

Start with 16:8 intermittent fasting before progressing to prolonged fasts. In winter, use bone broth (if approved by your doctor) for electrolyte balance to ease joint pain. Stay consistent with 2-3 fasts per month rather than frequent long ones that increase stress. Combine with my simple movement protocols — 10-minute chair exercises that fit busy schedules without gym intimidation.

Results from my clients show 8-15 pounds lost in the first 90 days when fasting respects seasonal cortisol patterns. Focus on sleep, as poor rest amplifies stress hormones and blocks autophagy. This isn't another impossible diet — it's sustainable support for hormonal shifts that make weight loss harder after 45.

💬 What the Community Says

The community shows mixed experiences with seasonal prolonged fasting. Many in their late 40s and early 50s report easier adherence during winter months, citing less heat-related fatigue and fewer social eating events. A common theme is frustration with elevated stress and cortisol disrupting autophagy benefits, especially among those managing diabetes or blood pressure. Beginners frequently share that joint pain makes long fasts feel harder in summer humidity, while others note winter blues can worsen emotional eating post-fast. There's ongoing debate about ideal timing, with some swearing by physician-monitored winter fasts for better insulin response and others preferring shorter summer fasts to avoid holiday stress. Insurance barriers and past diet failures lead many to appreciate practical, low-cost approaches shared in forums, though a vocal minority warns against self-prescribed extended fasts without medical guidance. Overall, lived experiences highlight the need for personalization around hormonal changes and daily schedules.
Clark, R. (2026). Do you prefer to do prolonged fasting (to induce autophagy) in the summer or win. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/do-you-prefer-to-do-prolonged-fasting-to-induce-autophagy-in-the-summer-or-winter-and-the-role-of-cortisol-and-stress-hormones
Russell Clark, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

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