Expert Q&A

Lost 3 and a half kg in my first 3 days…is this normal: how to talk to your doctor about this

Understanding Your Rapid Initial Drop

Losing 3.5 kg in the first three days is surprisingly common for beginners, especially those over 45 dealing with hormonal changes. In my work with thousands of patients through the CFP Weight Loss method, this early drop is rarely pure fat. Instead, it reflects glycogen depletion and water weight loss. Each gram of glycogen holds about 3-4 grams of water; when you reduce carbs or calories sharply, your body releases this stored fluid. For someone with insulin resistance or diabetes, this effect can be even more pronounced as blood sugar stabilizes.

Expect 0.5-1 kg of true fat loss per week after this initial phase. The first week often shows 2-5 kg total because of reduced inflammation and sodium shifts. If you're experiencing joint pain, this fluid reduction can actually ease discomfort, making movement feel more possible despite past exercise struggles.

When to Celebrate Versus When to Monitor

This pace isn't sustainable or healthy long-term. True metabolic change from the CFP approach focuses on sustainable fat loss of 0.5-1% of body weight weekly. Losing faster risks muscle loss, which slows metabolism further—exactly what many middle-income adults fear after failed diets. Track symptoms: dizziness, fatigue, or constipation signal you may need to increase electrolytes or protein. Those managing blood pressure should monitor readings daily, as fluid shifts can affect them.

In my book, I emphasize rebuilding confidence by distinguishing "scale wins" from real progress. Measure waist circumference and energy levels too. If your 3.5 kg includes significant bloating reduction, that's a win for hormonal balance.

How to Talk to Your Doctor About Rapid Weight Loss

Many feel embarrassed discussing obesity or quick results, especially when insurance won't cover programs. Prepare by logging your daily intake, symptoms, and measurements for two weeks. Start the conversation: "I've started a structured eating pattern and lost 3.5 kg in three days. My blood sugar feels steadier, but I'm concerned about sustainability. Can we check my electrolytes and thyroid?"

Bring specific questions: "Given my age and joint issues, how do we protect muscle while continuing?" Share that conflicting nutrition advice overwhelmed you before, and this feels different. Most doctors respond positively to data-driven patients. Request basic labs—comprehensive metabolic panel, A1C, and lipid profile—to track diabetes and blood pressure improvements. If they seem dismissive, ask for a referral to a registered dietitian covered by insurance.

Building Sustainable Momentum After the Initial Loss

Transition now to the core CFP principles: balanced plates with 30g protein per meal, consistent meal timing within your schedule, and gentle movement that respects joint pain. Walk 10-15 minutes after meals instead of gym intimidation. This prevents rebound and addresses the hormonal barriers making weight harder to lose after 45. Reassess in two weeks—most see another 1-2 kg drop while feeling energized, not deprived. Remember, real success rebuilds trust in your body after years of diet failure.

💬 What the Community Says

In online forums, many adults aged 45-55 report losing 2-4 kg in the first few days of new programs and wonder if it's normal. The community is split between excitement about the "whoosh" effect from water weight and worry it signals muscle loss or unsustainable restriction. Beginners with hormonal issues or diabetes often share that doctors dismissed early losses until they presented symptom logs and lab requests. A vocal minority describes joint pain easing quickly, boosting confidence to continue despite insurance limitations and time constraints. Most practitioners find discussing results gets better responses when focusing on blood pressure improvements rather than the scale alone. Lived experiences highlight embarrassment fading once they realize rapid starts are common but require follow-up monitoring to avoid yo-yo patterns seen in past diet attempts.
Clark, R. (2026). Lost 3 and a half kg in my first 3 days…is this normal: how to talk to your doct. *CFP Weight Loss*. https://blog.cfpweightloss.com/ask/lost-3-and-a-half-kg-in-my-first-3-days-is-this-normal-how-to-talk-to-your-doctor-about-this
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.

Have a follow-up question?
More Questions 200 answered
Newb question: focusing on perceived exertion or heart rate — how a functional medicine approach differs Any advice for someone new to weight watchers? Anyone have recipes or grocery lists — how a functional medicine approach differs Fitter or kidding myself when you have PCOS or hormonal imbalances How to avoid loose skin on Mounjaro: what to track and how to measure progress DO NOT TAKE INOSITOL IF YOU'RE NOT INSULIN RESISTANT if you're on a GLP-1 like semaglutide or tirzepatide DO NOT TAKE INOSITOL IF YOU'RE NOT INSULIN RESISTANT 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… Does Autophagy eat fat cells while doing intermittent fasting 📗 The 30-Week Tirzepatide Reset — Get Russell's complete protocol → Semaglutide + lifting — how are you fueling workouts on low calories and the role of cortisol and stress hormones What is your best way to shift focus when starting and changing your HRT while doing intermittent fasting So if you're spacing out your shots - what are y'all doing with extra injectors and the role of cortisol and stress hormones When people ask how I can tell my sugar's low and its effect on metabolism and insulin levels Shot doesn’t feel like it’s going into skin - bad batch? When feeling down, remember that PCOS is what helped our ancestors survive and the role of cortisol and stress hormones 📖 Satiety Signal — The biological 'off switch' for hunger that our protocol restores by healing the gut and balancing blood sugar levels. What has autophagy cured/made better in you and the role of cortisol and stress hormones Started at 270 pounds at the beginning of last year, at the end I was 179 pounds! How do I look for people with insulin resistance Sometimes after I take my Mounjaro shot I see this at the spot I gave the shot. Anyone know why on a low-carb or ketogenic diet 📖 Ketogenic Foundation — Using low-carbohydrate principles to keep insulin low, allowing the tirzepatide to work more effectively at lower doses. 📗 The 30-Week Tirzepatide Reset — Get Russell's complete protocol → Dr Gundry: the 120+80 supplements he himself takes daily and how it connects to gut health and inflammation What is Zone2 for a 66 year old Male on a low-carb or ketogenic diet Guys, did you know the POWER of exercise for your body and its effect on metabolism and insulin levels 📖 Rebound Weight Gain — The common 'yo-yo' effect caused by high-dose, continuous GLP-1 use; we prevent this through strategic cycling and metab… Estradiol Cypionate- I’ve been underdosing- what dose are you at on a low-carb or ketogenic diet Fitter or kidding myself — what do certified weight loss coaches recommend? Has anyone reversed insulin resistance without medication: how to talk to your doctor about this How can I boost metabolism without building muscle and the role of cortisol and stress hormones Do I need a dose change and the role of cortisol and stress hormones 📖 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… Has anyone lost weight on this diet — how a functional medicine approach differs How much fruit, chocolate, or dairy is too much: what to track and how to measure progress 📗 The 30-Week Tirzepatide Reset — Get Russell's complete protocol → When period stopped did you feel like the worst pmdd of all time daily or for people with insulin resistance Oval twice a week patch - what was I using — how a functional medicine approach differs Can I get an upvote for the true enemy of diabetes: how to talk to your doctor about this Anyone with a variant of uncertain significance on HRT and its effect on metabolism and insulin levels 📖 Metabolic Flexibility — The body’s ability to efficiently switch between burning carbohydrates and burning stored body fat based on availability… Flexibility in the meal plan while doing intermittent fasting Dr Gundry: the 120+80 supplements he himself takes daily and the role of cortisol and stress hormones Did exercise ever get rid of fatigue from insulin resistance while doing intermittent fasting When feeling down, remember that PCOS is what helped our ancestors survive for people with insulin resistance 📖 Autophagy — The body's natural 'housecleaning' process that occurs during fasting or low-insulin states, promoted during our mainten… How much fruit, chocolate, or dairy is too much and its effect on metabolism and insulin levels 📗 The 30-Week Tirzepatide Reset — Get Russell's complete protocol → Countries with easy access to grass-fed brains and fat and its effect on metabolism and insulin levels I'hv just stumbled upon autophagy and felt some hope for my situation. Is it really good for loose skin ? What can I do — what most people get wrong about this Is it normal to gain 3 lbs back after a sudden 6 lb weight loss? Same Workout Until it becomes Zone 2 — what do certified weight loss coaches recommend? Two week pause, ok to return to current dose and its effect on metabolism and insulin levels Has anyone been diagnosed with Hashimotos after going through emotional distress or chronic stress in general for those with hypothyroidism or Hashimoto's 📖 Cellular Detox — The process of clearing out metabolic waste and reducing cellular stress to allow for more efficient energy production a… When men recognize symptoms: how to talk to your doctor about this Astounded to see that 19 million people in the US are on levothyroxine. Why is hypothyroidism so prevalent? What is causing such crazy high levels of thyroid disease while doing intermittent fasting How I reversed insulin resistance in 6–8 months — what do certified weight loss coaches recommend? Anyone Here Successfully Reversed Insulin Resistance? What Actually Worked when you have PCOS or hormonal imbalances 📖 Refined Carbohydrates — Processed sugars and flours that strip the body of nutrients while driving the hormonal chaos responsible for the modern… 📗 The 30-Week Tirzepatide Reset — Get Russell's complete protocol → Has anyone used Willow for people with insulin resistance What’s the smallest habit that helped your insulin resistance the most: how to talk to your doctor about this Biochemistry. Its about: 55 % metabolism and interrelation, 15 % DNA, 10% protein, 20 % of tooth biochemistry and cancer. I have only pictures of this example test given to me so I can't post it and how it connects to gut health and inflammation How to BOOST metabolism and BURN fat-- VERY EASY AND QUICK — how a functional medicine approach differs