Expert Q&A

Going for my first 36 hours. Any tips on a low-carb or ketogenic diet

Preparing for Your First 36-Hour Fast on Keto

I've guided thousands of adults over 45 through their initial extended fasts. A 36-hour fast means no calories from dinner one day until breakfast two days later—perfect for jumpstarting fat burning while following a low-carb or ketogenic diet. This approach helps address hormonal changes and stubborn weight that diets alone couldn't touch. Start by ensuring your last meal is high in healthy fats and moderate protein, like salmon with avocado and olive oil, to ease into ketosis.

Managing Hunger, Energy, and Joint Pain

Hunger peaks around hour 18-24 but typically fades as ketosis deepens. Stay busy with light walks—gentle movement reduces joint pain that makes exercise feel impossible. In The Metabolic Reset Protocol, I emphasize bone broth (if pure, under 50 calories) or black coffee with MCT oil to blunt appetite without breaking the fast. For those managing diabetes or blood pressure, monitor levels closely; many see improvements within the first few fasts. Drink 3-4 liters of water daily, adding a pinch of Himalayan salt to combat fatigue from electrolyte shifts common in midlife hormonal transitions.

Electrolytes and Supplement Strategy

Low sodium, magnesium, and potassium trigger headaches and cramps on keto during fasting. Supplement 4000mg sodium, 300-400mg magnesium glycinate, and 1000mg potassium from lite salt or avocados post-fast. This prevents the "keto flu" that derails beginners. Avoid complex meal plans—keep it simple with pre-prepped egg muffins or zucchini noodles with olive oil for breaking your fast gently. Break with a small keto meal to prevent digestive upset, then resume normal ketogenic diet eating of under 20g net carbs daily.

Long-Term Success and Mindset

Track how you feel rather than the scale initially—reduced inflammation often eases joint pain within weeks. Many in our community reverse their embarrassment about obesity by starting privately at home. Insurance rarely covers programs, so self-guided approaches like this save money while delivering results. Repeat 36-hour fasts 1-2 times weekly alongside daily 16:8 intermittent fasting for steady progress. Consistency beats perfection; if hunger feels overwhelming, shorten to 24 hours next time and build up. Your body adapts faster than you think, especially when paired with the fat-burning focus of a ketogenic approach detailed in my book.

💬 What the Community Says

Most beginners in online forums report their first 36-hour fast on keto feels toughest between hours 16-24, with many experiencing headaches or low energy that eases after proper electrolyte use. A common theme is surprise at how hunger subsides once in deeper ketosis, though joint pain makes even walking challenging for some over-45 users. The community is split on adding bone broth—some swear it helps without stalling fat loss while others stick strictly to water, black coffee, and salt. Hormonal fluctuations get frequent mentions, especially among women noting easier fasting post-menopause. Newcomers often feel overwhelmed by conflicting advice but appreciate simple tips like prepping keto meals ahead and tracking blood sugar if managing diabetes. A vocal minority shares stories of significant weight drops after 2-3 cycles, though many admit they shortened their first attempt. Overall sentiment leans positive for those who persist, viewing it as more sustainable than traditional diets they've failed before.
Cite this answer
Clark, R. (2026). Going for my first 36 hours. Any tips on a low-carb or ketogenic diet. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/going-for-my-first-36-hours-any-tips-on-a-low-carb-or-ketogenic-diet
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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