Expert Q&A

Starting my second extended fast tomorrow. Hoping for 12 days or maybe do another 42?

Assessing Your Readiness for Extended Fasting

I see many in their mid-40s to mid-50s attempt extended fasting after years of diet frustration. Your second fast shows commitment, but jumping to 42 days requires careful evaluation. At this stage, focus on metabolic flexibility rather than extreme duration. Most beginners with insulin resistance, high blood pressure, or joint discomfort benefit from building tolerance gradually.

Review your first fast's outcomes: energy levels, blood glucose readings, and any electrolyte imbalances. Hormonal shifts in perimenopause or andropause can intensify during prolonged calorie restriction, making weight loss plateaus more likely without proper support. If your first experience left you drained or triggered cravings, cap this at 12 days.

12 Days vs 42 Days: Realistic Expectations

A 12-day water fast or bone broth fast aligns better with our CFP methodology for sustainable results. Expect 8-15 pounds lost, primarily water and fat once glycogen depletes around day 3. This length minimizes muscle loss while improving insulin sensitivity—key for those managing diabetes alongside obesity.

A 42-day fast, inspired by some therapeutic protocols, demands medical supervision, especially with existing conditions. Beyond 14 days, risks include electrolyte depletion, slowed metabolism, and exacerbated joint pain from inflammation changes. In my book, The CFP Fasting Blueprint, I outline how 5-14 day cycles repeated quarterly outperform single marathons for middle-income adults balancing work and health. Track ketones above 1.5 mmol/L and blood pressure daily.

Practical Protocols to Minimize Discomfort

Prepare with a 3-day low-carb ramp-down: under 30g net carbs daily. During the fast, consume 2-4 liters of water with Himalayan salt (2-4g sodium), magnesium (400mg), and potassium (1g from lite salt). For joint pain, gentle walks of 10-15 minutes prevent stiffness without strain—our clients report 40% less discomfort after day 5 as inflammation drops.

Break your fast with bone broth then small portions of avocado or eggs. Avoid refeeding syndrome by limiting initial calories to 500 on day one post-fast. Supplement electrolytes aggressively if you have blood pressure meds; consult your doctor for adjustments. This approach sidesteps the overwhelm of complex plans while addressing hormonal barriers head-on.

Building Long-Term Success Beyond One Fast

Extended fasting works best as a tool within the CFP Cycle: 12-day fast, 4-week metabolic reset with 16:8 intermittent fasting, then maintenance. This prevents the rebound most experience after extreme diets. Focus on sleep (7-9 hours), stress reduction via 5-minute breathing, and protein intake of 1.2g per kg bodyweight post-fast to preserve muscle.

You're not alone feeling embarrassed about obesity or past failures—our community proves small, consistent steps yield 20-40 pound losses yearly without insurance-covered programs. Listen to your body; 12 days may deliver the reset you need without the risks of 42. Reassess at day 10 and extend only if labs and energy support it.

💬 What the Community Says

In online forums, users in their late 40s and early 50s express excitement about second extended fasts but share cautionary tales. Many report solid 10-15 pound losses on 10-14 day water fasts, noting improved blood sugar and less joint inflammation after day 4, yet a vocal group warns against 30+ day attempts without doctor oversight—citing fatigue, hair loss, and rapid regain. Beginners managing diabetes or hypertension frequently debate electrolyte mixes, with most agreeing homemade salt solutions beat commercial packets. Hormonal challenges in women draw mixed experiences; some praise cycle regulation while others felt mood swings intensified. The community splits on 42-day goals, viewing them as extreme for working adults, preferring repeated shorter fasts for sustainability. Newcomers often feel validated hearing similar insurance and time constraint struggles, fostering supportive threads around gradual protocols over heroic durations.
Cite this answer
Clark, R. (2026). Starting my second extended fast tomorrow. Hoping for 12 days or maybe do anothe. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/starting-my-second-extended-fast-tomorrow-hoping-for-12-days-or-maybe-do-another-42
Russell Clark, FNP-C, APRN, 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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