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://ask.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.

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