I can get mine to tell me two separate things within 5 minutes. Put no faith in that thing past the weight measurement.
It takes years for muscle to atrophy, not weeks. Do some pushups to reassure yourself.
Agreed, I wouldn’t put a lot of stock in those numbers.
That said, yes all weight loss will involve some muscle loss. Muscle is metabolically taxing and the body likes to not support and maintain it during a deficit.
If you really want to ensure you’re being as muscle sparing as possible. Make sure you’re not losing too quickly, aim to lose around or under 1% bodyweight a week. Make sure you’re getting enough protein, there’s lots of opinions on this but .5-1g per pound is going to cover most folks, activity levels, and goals. The last factor is sending some signals to the body by using those muscle, so including at least some resistance training into your routine.
Best of luck!
My experience is that I lost about a pound of muscle for every 4-5 pounds of fat when I was just fasting and not working out . I started weight training and was at about half the strength I had months before IF . It has been a long road to try and get it back without gaining fat . It just seems that I can either drop pounds quickly and lose muscle mass or I can eke out a 1 pound a week fat loss and maintain muscle mass . But gaining muscle mass while fasting (at least to me ) seems to be a myth . That being said , I’m sure people will comment about how it’s possible . This was just my experience over the last year and I’ve tried following advice from this sub and tweaking my plan here and there . The only real helpful thing was (for me ) not lifting at the end of my fast but rather 2-3 hours after breaking it .
Edit* - for clarity ; I’ve been on the heavy side most of my life but have also worked out . I always tried to “lean out” . When I started IF I decided to try something different and just lose a bunch of weight and THEN build back rather than the other way around - I went from 230 to 190 in four months but I really wasn’t happy with my physique. I’m at 200 now and still doing A 20-4 routine with more calories and protein. I think it’s a happy medium for now but I’m still tweaking it here and there for my personal goals.
Perhaps what’s throwing your scale off is your low carb diet, which reduces water retention in your body. Stored glycogen attracts water, once it’s used up your body drops a few kilos of water. It’s totally normal to lose some water when dieting and especially on low carb. That’s the water weight you might see being mentioned around the place.
Try just using waist measurement as your metric. Yes it’s normal to lose some muscle (and skin, and blood, and everything) when losing weight, you are just hoping to lose more fat than other stuff to get leaner.
Waist to height is the only proven metric for harmful fat (in terms of health). Waist getting smaller, or staying same size when gaining weight, means your body composition is improving. If you are 5’5” you are in healthy range if waist smaller than 32.5”.