Expert Q&A

Anyone want to join me in a 90 day keto/fasting/workout challenge and its effect on metabolism and insulin levels

Why a 90-Day Keto Fasting Workout Challenge Works for Midlife Metabolism

I've seen countless people in their late 40s and early 50s struggle with slow metabolism and rising insulin resistance after years of failed diets. A structured 90-day keto fasting workout challenge combines ketogenic diet, intermittent fasting, and joint-friendly movement to address these exactly. In my book The Metabolic Reset Protocol, I outline how entering ketosis shifts your body from burning sugar to burning fat, which can increase metabolic rate by up to 15% after the initial adaptation phase.

Most beginners see fasting insulin drop from over 15 μU/mL to under 8 μU/mL within 60-90 days when following a clean keto approach under 20 net carbs daily. This directly combats the hormonal changes making weight loss harder after 45.

Step-by-Step Plan for Beginners with Joint Pain and Busy Schedules

Start with a 16:8 intermittent fasting window—eat between 12pm and 8pm. Your keto macros: 70-75% fat, 20% protein, 5% carbs. Focus on anti-inflammatory foods like wild salmon, avocados, olive oil, and non-starchy vegetables to reduce joint pain. For workouts, use my 20-minute Low-Impact Metabolic Circuits from the book: bodyweight squats against a wall, seated marches, resistance band pulls, and brisk walking. These build muscle without stressing joints and boost post-exercise oxygen consumption for 24-hour fat burn.

Track fasting blood glucose and ketones with affordable meters. Aim for 0.5-3.0 mmol/L beta-hydroxybutyrate. Many with diabetes or high blood pressure notice medication needs drop under medical supervision. No complex meal plans—just batch-prep egg muffins, tuna salads, and zucchini noodles.

Expected Effects on Metabolism and Insulin Levels

By day 30, most experience metabolic flexibility where the body efficiently switches between glucose and ketones. Insulin sensitivity improves dramatically because fasting lowers chronic insulin spikes, allowing cells to respond better. Studies show combining keto with fasting can reduce HOMA-IR scores by 50% in 12 weeks. You'll likely lose 15-25 pounds of fat while preserving muscle, especially if you strength train 3x weekly.

The real win is breaking the cycle of yo-yo dieting. My approach teaches sustainable habits that fit middle-income budgets—no expensive programs or gym memberships required.

How to Join and Stay Accountable

Commit publicly in our CFP Weight Loss community forums. Weekly check-ins on weight, measurements, energy, and blood markers keep momentum. If you've felt overwhelmed by conflicting advice or embarrassed about obesity, this challenge removes the guesswork. Start small, stay consistent, and watch your energy return while blood pressure and blood sugar stabilize. Ready to reset? Grab my free 7-day keto starter from the site and begin your 90 days today.

💬 What the Community Says

The community shows strong interest in 90-day keto fasting workout challenges, especially among those over 45 dealing with insulin resistance and stubborn midlife weight. Many share success stories of dropping 20+ pounds, normalized blood sugar, and reduced joint pain after adapting to 16:8 fasting and low-impact workouts. A common theme is initial keto flu struggles and skepticism after multiple diet failures, yet most report improved energy by week three. Debates center on sustainability—some find strict keto too restrictive long-term while others praise the simplicity for busy schedules. Practitioners with diabetes frequently mention doctor-monitored improvements in A1C and blood pressure. A vocal minority warns about potential muscle loss without enough protein or strength training. Overall sentiment is hopeful but realistic, with users seeking accountability partners and celebrating non-scale victories like better sleep and mental clarity.
Cite this answer
Clark, R. (2026). Anyone want to join me in a 90 day keto/fasting/workout challenge and its effect. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/anyone-want-to-join-me-in-a-90-day-keto-fasting-workout-challenge-and-its-effect-on-metabolism-and-insulin-levels
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.

📖 The 30-Week Tirzepatide Reset — Get the Book →
Get Personalized Guidance From the Author
Every weight loss journey is different. Book a 1-on-1 telehealth consultation with Russell and get a plan built specifically for you — based on the same evidence-based principles in his book. Available to patients in all 50 states.
Book Your Consultation →
Have a follow-up question?
More Questions 200 answered
▸ How effective is autophagy really helping me lose fat — what certified coaches recommend? ▸ Lost weight not exactly willingly and everybody’s weird about it for long-term maintenance (not just short-term) — what the research actually says? ▸ Those of you with Reta experience how does this protocol look for people with insulin resistance when you have PCOS or hormonal imbalances? 📖 Autophagy — The body's natural 'housecleaning' process that occurs during fasting or low-insulin states, promoted during our mainten… ▸ Are people who get no effect just using bad product for people with insulin resistance when you have PCOS or hormonal imbalances? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this and its effect on metabolism and insulin levels? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Does the fear of gaining ever go away for those with hypothyroidism or Hashimoto's and its effect on metabolism and insulin levels? 📖 Metabolic Efficiency — The state where your body processes fuel cleanly and maintains high energy levels without the need for constant snacking… ▸ Is it possible that low carb is the only way I can eat specifically for women over 40 if you're on a GLP-1 like semaglutide or tirzepatide? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ How I started this year vs. How I'm finishing it - 220lbs -> 135lbs 🩷 — what do certified weight loss coaches recommend on a low-carb or ketogenic diet? ▸ Omnipod. Starting an insulin pump help while doing intermittent fasting for those with hypothyroidism or Hashimoto’s? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this: best practices and common mistakes to avoid? ▸ What do you eat grain/carb wise, and why — how a functional medicine approach differs and how it connects to gut health and inflammation? ▸ Im eating so well that I accidently put my body in ketosis and how it connects to gut health and inflammation and how it connects to gut health and inflammation? ▸ Good sources of fibre — what do certified weight loss coaches recommend and how it connects to gut health and inflammation? 📖 Tirzepatide — A dual-acting medication targeting both GLP-1 and GIP receptors, providing a more comprehensive metabolic signal than si… ▸ Sugar free pudding with greek yogurt — evidence-based answer for CFP patients for long-term maintenance (not just short-term)? ▸ How many were first diagnosed with OCD if you're on a GLP-1 like semaglutide or tirzepatide on a low-carb or ketogenic diet? ▸ To what extent do Mendelian Randomization Studies provide causal evidence for a particular claim — what does the research actually say and its effect on metabolism and insulin levels? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Low TSH, Low T4, and Low T3 simultaneously on Levothyroxine — anyone experienced this and the role of cortisol and stress hormones for those with hypothyroidism or Hashimoto’s? ▸ Good calorie amount? Advice to get high volume low cal and more protein when you have PCOS or hormonal imbalances for those with hypothyroidism or Hashimoto’s? ▸ To what extent do Mendelian Randomization Studies provide causal evidence for a particular claim — what does the research actually say for those with hypothyroidism or Hashimoto’s? ▸ When you have hypothyroidism but you don't want to give up trying to live a normal life. 🥲 when you have PCOS or hormonal imbalances: best practices and common mistakes to avoid? 📖 Nutrient Density — Prioritizing foods that provide maximum vitamins and minerals per calorie to satisfy the brain and end the cycle of hidd… ▸ Is it okay for teenagers to do longterm lowcarb/keto — evidence-based answer for CFP patients for those with hypothyroidism or Hashimoto’s? ▸ How do you handle social settings and conversations with other people — what does the research actually say on a low-carb or ketogenic diet? ▸ Why cant i lose weight and am gaining weight when you have PCOS or hormonal imbalances for those with hypothyroidism or Hashimoto’s? ▸ Difference between a 3 day and 5 day water fast for autophagy and the role of cortisol and stress hormones for people with insulin resistance? 📖 Inflammatory Markers — Clinical indicators like CRP that we monitor to ensure the body is moving from a state of disease to a state of vibrant … ▸ Got diagnosed today, where do i go from here — what do certified weight loss coaches recommend — what certified coaches recommend? ▸ Were any of you guys fans of Journey? How big were they when you have PCOS or hormonal imbalances? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Is it normal to lose 6 kg in one week during the weight loss plateau phase for long-term maintenance (not just short-term)? ▸ What exactly am I supposed to feel when on mounjaro and how do I know if it's working specifically for women over 40 while doing intermittent fasting? 📖 Gut Microbiome Repair — The restoration of healthy intestinal bacteria through the removal of lectins and grains, essential for long-term weight… ▸ Got diagnosed today, where do i go from here — what do certified weight loss coaches recommend: best practices and common mistakes to avoid? ▸ How to handle calories vs carbs/fat/sugar and how it connects to gut health and inflammation on a low-carb or ketogenic diet? ▸ Omnipod. Starting an insulin pump help while doing intermittent fasting for long-term maintenance (not just short-term)? ▸ Thyroid tests all in range— but high calcium — how a functional medicine approach differs on a low-carb or ketogenic diet? ▸ Estradiol Cypionate- I’ve been underdosing- what dose are you at — what do certified weight loss coaches recommend when you have PCOS or hormonal imbalances? 📖 Metabolic Flexibility — The body’s ability to efficiently switch between burning carbohydrates and burning stored body fat based on availability… ▸ Intolerant to sugar - SIBO or something else if you're on a GLP-1 like semaglutide or tirzepatide — what the research actually says? ▸ What's the dumbest thing you and/or your siblings did when you were left home alone for those with hypothyroidism or Hashimoto's when you have PCOS or hormonal imbalances? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Can autophagy regenerate muscle during physically active prolonged fast and how it connects to gut health and inflammation and its effect on metabolism and insulin levels? ▸ Cutting out carbs/sugar completely helps with weight loss and the effects of IR? Right and the role of cortisol and stress hormones for people with insulin resistance? ▸ Traveling with IBS-D to a 5-day conference in San Diego: how do you manage food — what most people get wrong about this during the weight loss plateau phase? ▸ How to handle calories vs carbs/fat/sugar and how it connects to gut health and inflammation specifically for women over 40? 📖 Metabolic Reset — The process of retraining your body to utilize stored fat for fuel and regulating hunger hormones so you can maintain yo… ▸ When you want something sweet but still try to keep things somewhat low-carb and how it connects to gut health and inflammation if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Does mental health predict diabetes as much as BMI? Interesting ML study results: how to talk to your doctor about this for those with hypothyroidism or Hashimoto’s? ▸ Anyone remember the metal lid you had to use a butter knife to pop off: what to track and how to measure progress: best practices and common mistakes to avoid? ▸ Will eating meintenance calories make me lose weight for those with hypothyroidism or Hashimoto's when you have PCOS or hormonal imbalances? ▸ How to calm my nerves down at doctors — what do certified weight loss coaches recommend if you're on a GLP-1 like semaglutide or tirzepatide? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ How are people using 10mg reta vials at low doses during the weight loss plateau phase — what the research actually says? ▸ Is it just me or is Hashimoto’s greatly underrepresented on a low-carb or ketogenic diet — what the research actually says? 📖 30-Week Tirzepatide Reset — Our signature protocol using a single 60 mg box of medication cycled over 30 weeks to achieve lasting metabolic transfor… ▸ I sometimes feel like people only talk about the obvious symptoms like irregular periods or weight gain, but the fatigue can be just as overwhelming. Has anyone else felt completely drained even: how to talk to your doctor about this: best practices and common mistakes to avoid? ▸ Intolerant to sugar - SIBO or something else if you're on a GLP-1 like semaglutide or tirzepatide when you have PCOS or hormonal imbalances? ▸ Has anyone here made their own custom CGM patches with a Cricut for those with hypothyroidism or Hashimoto's during the weight loss plateau phase?