How can I tell if I am losing body fat or muscle?

I have started cutting after I realized that I am around 24% body fat. I have a body fat scale at home it's called SONGYIN and I knew they are not accurate but I thought it could at least give me some guides but it is driving me insane because I can see that I am losing body weight at a normal rate weekly however on the scale I see that I am losing fat way less than I am losing bodyweight. here is some data from my home scale:

Age: 39
Hight: 172cm

First week: weight 71.1 kg / BF 24.2% / waist 87cm
2nd week: weight 69.6 kg / BF 23.6% waist 86cm
3rd week: weight 69.4 kg / BF 23.5% waist 85cm
4th week: weight 68.7 kg / BF 23.2% waist 84.5cm

I am also recording some of my exercises diary including reps and weight and I don't see any negative changes in that, actually, I am making a bit of progress either in reps or weight. I think I also eat enough protein daily around 137g.

I have attached a couple of photos, can you tell from the picture how much BF% I have?


Do you think I am losing muscle mass? Any advice would be highly appreciated.


  • kshama2001
    kshama2001 Posts: 25,610 Member
    @ninerbuff is a trainer who is good at guessing BF - hopefully he will see this ping and weigh in.
  • sijomial
    sijomial Posts: 19,606 Member
    edited February 12
    Remember that you are not just made up of fat and muscle - you are fat and lean tissue.
    That includes blood volume, connective tissue, skin - in fact everything that's not fat.

    Even if you are maintaining all your existing muscle a person getting smaller will still expect to be seeing reductions in lean mass while losing weight.

    Your rate of weight loss is nice and sensible and your scale's estimate doesn't look unreasonable.
    You also need to take into account your weight is in KGs but your body fat is given as a percentage so you would have to work out the (very estimated!) KG of fat and fat loss at each weigh in.

    As you are saying you are doing the right things (sensible rate of loss, strength training, higher protein levels) it's not unreasonable to think you are doing well.
  • AnnPT77
    AnnPT77 Posts: 24,744 Member
    You will lose the maximum amount of fat (vs. lean tissue) if you:

    * Lose weight slowly
    * Get good nutrition (especially but not exclusively adequate protein)
    * Get exercise, especially strength exercise

    The scale is not going to be an accurate fat indicator week to week. At best, it may outline a trend direction, and even then there can be some misleading outlier readings. (I have a scale like that; I pretty much ignore the BF% number.)

    As Sijomial said, you would want to lose some lean body mass: If at 57kg I had the same blood volume I had at 83kg, I think that would look pretty bad, let alone the health implications, y'know?

    Keep in mind that the same percent of a smaller number is itself a smaller number. If we believed your scale, with your weigh-ins converted to fat/lean kgs:

    First week: weight 71.1 kg / BF 24.2% / waist 87cm = 17.2kg fat, 53.9kg lean mass
    2nd week: weight 69.6 kg / BF 23.6% waist 86cm = 16.4kg fat, 53.2kg lean mass
    3rd week: weight 69.4 kg / BF 23.5% waist 85cm = 16.3kg fat, 53.1kg lean mass
    4th week: weight 68.7 kg / BF 23.2% waist 84.5cm = 15.9kg fat, 52.8kg lean mass

    It's possible to gain muscle mass (which is different from lean mass, remember) in a calorie deficit (i.e., while losing weight), but it would be likely to be quite slow. Mostly, you'd be looking to preserve muscle. Any gain on top of that is a bonus. (Strength increases faster than muscle mass, especially if new to strength exercise.) In that kind of context, those numbers don't seem bad to me . . . if we believed the scale, which personally I wouldn't.

    If you're doing the things on the asterisked list at the start of this post, you're pretty much doing what you can.

    Hang in there, keep doing the good stuff, you'll get the best results that are achievable.
  • Theoldguy1
    Theoldguy1 Posts: 2,270 Member
    The 24% BF is probably in the ballpark. Over 4 weeks not really possibly to tell if losing muscle or fat. Your doing fine.
  • JBanx256
    JBanx256 Posts: 1,172 Member
    Some good signs:
    -your waist is shrinking
    -your strength is at least stable, if not improving
    -you're losing at a sensible rate
    -you're getting a decent amount of protein

    I really would put zero faith in the scales as far as bodyfat goes, TBH. They *CAN* be a reasonable indicator of some sort of trend one way or another, but an extra glass of water or a couple days without a good poo and then BAM, your trend is skewed, Nah. I personally completely disregard the bf% thing on my bathroom scales, but that's just me.

    If I had to guess, I'd put your bf% in the low 20's. This is far from perfect, but it's at least a ballpark idea based purely on visuals:

  • PAV8888
    PAV8888 Posts: 10,670 Member
    edited February 12
    Bio impedence scale readings are generally speaking garbage.

    Looking at Ann's numbers you're still losing fat at a better than 1:1 ratio to lean mass.

    Is that ideal? No. 2:1 would be better, right? But it's still not 0.25 to 1!🙀

    You can only do what you can do. Good exercice stimulus. Reasonable deficit. Good protein intake. Adequate sleep. And ignore random numbers! 🤷🏻‍♂️😹