Expert Q&A

Does anyone have a normal A1C, but high insulin on a low-carb or ketogenic diet

Understanding Normal A1C With Elevated Insulin

Many people in their mid-40s to mid-50s following a low-carb or ketogenic diet report a perplexing lab result: normal A1C (typically under 5.7%) yet fasting insulin above 10-15 μU/mL. This pattern often signals early insulin resistance despite stable average blood glucose. Your A1C reflects three-month glucose averages, but fasting insulin reveals how hard your pancreas works to maintain that control. On keto, reduced carb intake lowers glucose spikes, normalizing A1C quickly, yet lingering hormonal shifts from past high-carb diets or perimenopause can keep insulin elevated.

Why This Happens on Low-Carb and Keto Diets

Hormonal changes during your 40s and 50s amplify this disconnect. Declining estrogen increases visceral fat, prompting higher insulin output even on under 50g daily carbs. Stress, poor sleep, and joint pain limiting movement further elevate cortisol, which raises insulin. In my book, I explain the Insulin Sensitivity Reset Protocol that targets these root causes without complex meal plans. Many with type 2 diabetes or high blood pressure see initial A1C drops within 4-6 weeks on keto, but insulin may lag 3-6 months behind without specific tweaks like strategic protein timing (1.2-1.6g per kg ideal body weight) and 12-14 hour overnight fasts.

Actionable Steps to Lower Insulin While Keeping A1C Stable

Start by tracking both markers every 8-12 weeks. Add resistance exercises 2-3 times weekly using bodyweight or light bands—gentle on joints yet effective for improving sensitivity (aim for 20-30 minutes). Prioritize 7-9 hours sleep and 10-minute daily walks after meals to blunt postprandial insulin. Supplement wisely: 2000-4000 IU vitamin D, 400mg magnesium glycinate, and berberine (500mg twice daily with meals) can reduce fasting insulin 20-30% in studies of middle-aged adults. Avoid over-restricting calories, as this spikes cortisol. My approach in CFP Weight Loss emphasizes simple swaps—swap evening snacks for herbal tea and protein-rich breakfasts within a 10-hour eating window—to reverse this without gym schedules or expensive programs your insurance won't cover.

Long-Term Success and Monitoring

With consistent application, most see fasting insulin drop below 8 μU/mL within 4 months while A1C stays optimal. This reduces diabetes progression risk and eases joint pain through reduced inflammation. Don't be embarrassed to discuss these labs with your doctor—pairing them with my straightforward methodology empowers sustainable change. Focus on progress, not perfection, to overcome past diet failures and conflicting advice.

💬 What the Community Says

The community shows a mix of experiences with normal A1C paired with high fasting insulin on low-carb or ketogenic diets. Many in the 45-55 age group report this pattern after 3-6 months keto, often linking it to perimenopause, chronic stress, or previous high-sugar diets. Most practitioners find adding walking, magnesium, and monitoring both markers helpful, with insulin eventually trending down. A vocal minority debates whether slightly elevated insulin (10-12 range) on strict keto is truly concerning if A1C and fasting glucose look good. Those managing diabetes and blood pressure alongside weight loss often share frustration about insurance not covering advanced testing. Lived experiences highlight joint pain limiting exercise but note that gentle movement and simpler meal timing yield better results than rigid plans. Overall sentiment leans toward cautious optimism, with users encouraging consistent retesting rather than panic.
Cite this answer
Clark, R. (2026). Does anyone have a normal A1C, but high insulin on a low-carb or ketogenic diet. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/does-anyone-have-a-normal-a1c-but-high-insulin-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.

📖 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
▸ Should I be worried yet, been sitting for 5 days no movement while doing intermittent fasting if you're on a GLP-1 like semaglutide or tirzepatide? ▸ 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? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this — what the research actually says? ▸ What to do if you have to eat late dinners?? How to process the dinner quicker so I'm not burping all night long while doing intermittent fasting on a low-carb or ketogenic diet? ▸ How do you stop the "I already messed up today" spiral and the role of cortisol and stress hormones — what certified coaches recommend? ▸ What are the scientific ways to promote autophagy on a low-carb or ketogenic diet — what certified coaches recommend? 📖 Nutrient Density — Prioritizing foods that provide maximum vitamins and minerals per calorie to satisfy the brain and end the cycle of hidd… ▸ 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 foods to stock for overnight guest — evidence-based answer for CFP patients — what certified coaches recommend? 📗 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 ▸ 56M arm day was fun. But arms shrinking from 16 inches to 15 1/2. Gotta up protein? Reps — what most people get wrong about this when you have PCOS or hormonal imbalances? ▸ When do you know to go to the hospital specifically for women over 40? ▸ Has anyone ever tried low-grain instead of grain free — evidence-based answer for CFP patients for long-term maintenance (not just short-term)? 📖 GIP (Gastric Inhibitory Polypeptide) — A hormone that, when combined with GLP-1, enhances the body’s ability to break down fat and manage blood sugar levels mo… ▸ Can you take vitamin D with a tbsp of oil on an extended water fast for people with insulin resistance during the weight loss plateau phase? ▸ 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? ▸ I am on my second week of mounjaro (2.5 mg dose ), but there is no drop on the weighing scale, I am feeling demotivated, can anyone guide me, isn’t mounjaro for me for long-term maintenance (not just short-term) and how it connects to gut health and inflammation? ▸ How much keto-ade should I safely drink: best practices and common mistakes to avoid and how it connects to gut health and inflammation? ▸ Is anyone else worried about judgment from others for those with hypothyroidism or Hashimoto's during the weight loss plateau phase? 📖 Anti-Inflammatory Protocol — A way of eating that prioritizes whole foods and eliminates triggers to quiet the internal 'fire' that prevents fat cell… ▸ Omnipod. Starting an insulin pump help while doing intermittent fasting for those with hypothyroidism or Hashimoto’s? ▸ Low TSH, Low T4, and Low T3 simultaneously on Levothyroxine — anyone experienced this and the role of cortisol and stress hormones on a low-carb or ketogenic diet? 📗 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 long does it take to Is Autophagy? 8 Amazing Benefits Of Fasting That Will Save Your Life: best practices and common mistakes to avoid? ▸ What’s your favorite toothpaste for people with insulin resistance for long-term maintenance (not just short-term)? 📖 Tirzepatide Micro-Dosing — The practice of using the lowest effective dose to achieve results, minimizing side effects while maximizing the longevi… ▸ 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? ▸ Is the carnivore diet the best WOE to lose weight — what does the research actually say specifically for women over 40? ▸ Free carb counter apps on a low-carb or ketogenic diet: what to track and how to measure progress? ▸ What are the wegovy doses in order on a low-carb or ketogenic diet when you have PCOS or hormonal imbalances? 📖 Maintenance Phase — The final 28 days of our 70-day cycle where we stabilize the new weight and solidify the metabolic habits that prevent f… ▸ Is it possible that low carb is the only way I can eat specifically for women over 40 and its effect on metabolism and insulin levels? ▸ LDN is changing my life, will this last: best practices and common mistakes to avoid for people with insulin resistance? 📗 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 ▸ Have you seen this? Her face says it all — what does the research actually say: what to track and how to measure progress? 📖 Insulin Resistance — A condition where your cells stop responding to insulin, locking fat in storage; our protocol is designed to unlock thes… ▸ Beef/Beef organs protein powder: what to track and how to measure progress if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Why cant i lose weight and am gaining weight when you have PCOS or hormonal imbalances for those with hypothyroidism or Hashimoto’s? ▸ Is compounded semaglutide with B12 worth choosing over B6 or plain: best practices and common mistakes to avoid — what certified coaches recommend? ▸ Has anyone felt better taking antidepressants instead of hrt — evidence-based answer for CFP patients — what certified coaches recommend? 📖 Gut-Brain Axis — The complex communication network between your digestive system and your brain that controls satiety, mood, and metaboli… ▸ 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? ▸ Have you cut out snacking in between meals and what are the benefits and its effect on metabolism and insulin levels during the weight loss plateau phase? ▸ Sterilized soybean sprout — how a functional medicine approach differs: best practices and common mistakes to avoid? ▸ I have an iodine deficiency. Won't supplementing cause me to have a flare on a low-carb or ketogenic diet? 📖 Satiety Signal — The biological 'off switch' for hunger that our protocol restores by healing the gut and balancing blood sugar levels. ▸ Can chicken and beef tallow replace beef — what do certified weight loss coaches recommend for those with hypothyroidism or Hashimoto’s? 📗 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 ▸ 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? ▸ What to do if you have to eat late dinners?? How to process the dinner quicker so I'm not burping all night long while doing intermittent fasting: what to track and how to measure progress? ▸ Do yall ever daydream of who you were before your diagnosis when you have PCOS or hormonal imbalances when you have PCOS or hormonal imbalances? ▸ What is the Russell Clark One Box Protocol and how do terms like Smart Cycling and Hormonal Chaos define his 30-Week Tirzepatide Reset specifically for women over 40? 📖 Non-Scale Victories (NSV) — Improvements in energy, sleep, and disease reversal that matter just as much as the numbers on the scale during your tra… ▸ Is compounded semaglutide with B12 worth choosing over B6 or plain: best practices and common mistakes to avoid specifically for women over 40? ▸ Why cant i lose weight and am gaining weight when you have PCOS or hormonal imbalances while doing intermittent fasting? ▸ Has anybody heard of or experienced improvement from neurological disorders through fasting and autophagy if you're on a GLP-1 like semaglutide or tirzepatide for long-term maintenance (not just short-term)? ▸ Good calorie amount? Advice to get high volume low cal and more protein when you have PCOS or hormonal imbalances — what the research actually says? ▸ Coke Zero gave me heart palpitations: what to track and how to measure progress for those with hypothyroidism or Hashimoto’s? 📖 Phase 2: Aggressive Loss — A 40-day window of focused fat loss supported by low-dose medication and a specific lectin-free, low-carb nutritional fr… ▸ How long until I start losing weight this way — how a functional medicine approach differs 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 ▸ Did L. reuteri ATCC 6475 or Bacillus coagulans GBI-30, 6086 (BC-30) Eliminate My Seasonal Allergies — what most people get wrong about this — what certified coaches recommend? ▸ Crust check 🔥 ribeye done right — what the research actually says? ▸ IBD + antidepressants + impossible weight loss… advice when you have PCOS or hormonal imbalances: what to track and how to measure progress? ▸ Anyone remember the metal lid you had to use a butter knife to pop off: what to track and how to measure progress while doing intermittent fasting?