Water Fasting for 10 Days & Muscle Loss

Saw a YouTuber named "The Unlazy Way" go on a water fast for 10 days. He was 85.2kg with 6.7kg fat and 45kg muscle on day 1. On the 10th day, he was 77.2kg with 6.5kg fat and 40.7kg muscle. (He lost 0.4kg of fat and 4.9kg of muscle). His BMI before was 23.4 and 21.2 after. Did he mostly lose muscle because he did not have excess fat in his body? I'm 90kg, 171cm (BMI = 30.8 kg/m2 ) and I want to go on a 10-day fast. I assume, most of the weight I lose will be fat because I've excess of it compared to the YouTuber I mentioned. Am I correct?

Answer

I am curious about this too. I want to try fasting but I am worried about losing muscle mass. I currently do IF (most days 2-4 hour feeding window) but I could certainly still lose a few pounds (6’-0” 170lbs) but I am an avid cyclist and relatively fit. Any science on this? Or anyone have success fasting without significant muscle loss?

Answer

understand that there is fat that you see and fat you do not

a lot of organs are surrounded with fat

the first few days will be mostly water after that fat will be shedded

about right 80kg after 10 days you will come down 75-70 kg

remember you have skin/bones/organs so 80kg about 50-60kg roughly of those things