Percent Composition of Weight Loss: Fat vs. Muscle vs. Other Lost

I’ve been using an impedance scale for many years to observe my weight, BMI, and %fat, paying little attention to the other available metrics. When the numbers get too high (with, coincidentally, both BMI and %fat approaching 30), I get serious and start tracking everything in a spreadsheet, as I get into diet and exercise mode to drive those numbers back down toward 25. This time I’m three months into a reasonably healthy diet and exercise program with 1200 balanced calories and walking 5 miles daily.

Now, here is where it got interesting. I used the export function of my Bluetooth scale to analyze my weight, %fat, and %muscle data starting 3/12/2018. Multiplying weight times %fat and %muscle gives me fat and muscle in pounds, and I also get “other” in pounds where other = weight - fat - muscle.

Given that I’d always known that my objective included burning fat without losing muscle, I now used this data to actually evaluate how well I’ve done. The results were surprising: Although from 3/12/2018 to 6/12/2018 I’d lost 37.6 pounds, and reduced my waist from 47 down to 40 (still an obese 0.60 waist-to-height ratio), the spreadsheet calculations told me I had lost only 23.9 pounds of fat. I had also lost 3.1 pounds of muscle, and 10.6 pounds of “other.”

While puzzling over what “other” loss meant, given the muscle loss, I went ahead and bought a Total Gym and started working on it daily, adding that exercise effort to my 5 mile daily walk. I then added a “Total Gym” reference line to the overall chart, now showing what fat and muscle loss looks like:

I’m still trying to pin down exactly what losing “other” means – hopefully it is losing the support structures and blood supply no longer needed because of adipocyte apoptosis. In the meantime, since now only about 53% of my weight loss this past week is fat – at least as far as what my impedance scale is counting towards my %fat, projections tell me I’ve still got to lose about another 29 pounds (putting me at rock bottom 18.5 BMI) to get my %fat below 12% and muscle above 33% with a healthier 33.5 inch waist (0.50 waist-to-height ratio).


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If you have the option, I’d do two DXA scans to see how accurate the weight scale is, one when you’re at 30% fat, and one when you’re at 20% fat. This will also tell you were the fat is, if it’s not obvious :slight_smile:

From a health point of view, what matters is belly fat, not BMI or total %fat.

Thanks Eric.

Although I’ve had my head in the sand for decades, I definitely agree with you on visceral fat being the most important criteria, not weight or BMI. I just kept falling off my diet before making much progress against a plateau at 160-169. There’s the old saying, when you are up to your butt in alligators it’s hard to remember the objective is to drain the swamp. But, excuses aside, this is my 7th try in 7 years, and I have FINALLY got a grip on the problem. I’m now down to 147.4 today and still losing 2 pounds per week.

Since I’m still planning on getting my 40" waist down to 33-34" to get rid of the unhealthy visceral fat, projections tell me I might need to lose another 29 pounds. That would put me at 118 pounds, the same as what I weighed when I enlisted in 1967, so that’s probably the lowest I’ll ever let myself get. (At 5’7 that will be back to an 18.5 BMI). After that, I’ll just have to settle for burning off the remaining excess fat while adding an equal weight in muscle.

Bottom line, I also agree with your suggestion to look into DXA scans. With the nudge you gave me, I found where I can do that, and am now in contact with a local company (DexaFit Orlando) to schedule it.

Kudos for your great reply. Thanks again.

Really interesting. Do you know what made the difference in taking you from the “yo-yo” phase to the steady weight loss phase?

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Hi Agaricus,

Thanks for the question. I showed only 7 yo-yo cycles in that chart because that was all the hard data I had. I’ve actually been doing it since 1991, beginning with a drop from 180 to 140 when I decided to run the 1991 USMC marathon – which I completed in 3 hours 45 minutes, missing the Boston Marathon qualifying time by only 20 minutes. Most of the subsequent yo-yo attempts were driven by a desire to repeat that marathon, losing weight while training – but never making it to the starting line again due to consecutive training injuries – and then regaining the weight for the next 6-18 months.

My other motivation in losing weight – even more important than weight, waist, and BMI – is my type II diabetes. When off my diet, I take morning readings that slowly rise until they reach 200 or more, which is when my “Danger Will Robinson” alarm wakes me up to get my diet back in gear. As soon as I start restricting my calories and closely monitoring glucose before and after every meal, the numbers drop rapidly to the 80-100 range. So my A1c fluctuates between diabetic 10.5 and non-diabetic 5.5, depending on whether I am dieting.

So perhaps the best answer to why I have kept failing is the old saying, those who fail to remember the past are doomed to repeat it, with the two biggest mistakes being unrealistic training goals and treating myself to fancy dinners and relaxing the constraints when reaching intermediate goals. Duh…

But what is also different this time is that I have changed my focus. When I first learned about BMI I created a “Reverse BMI” scale from 18 to 32, showing side-by-side what my weight would be at each BMI point (e.g., Lowest-Normal 18.5 = 118.1, Average-Normal 21.0 = 134.1, Overweight 25.0 = 159.6, Obese 30.0 = 191.5, etc.). So my short-term goal would be to get below 159.6, and long-term goal would be to get to 134.1. Over the years, my spreadsheet dashboard evolved until it became quite elaborate, now even acknowledging %muscle and the lost muscle mass referenced in my initial post.:

The problem, of course, is that these measures are insensitive to the health risks of the visceral fat that I never tackled directly, thinking that it would be solved if I ever got below “Overweight” on that scale. As it turned out, the linear projection estimate of future waist vs. weight in the green box never fit the reality, since I’d incorrectly assumed I’d be at 9.5% fat with a 32" waist at BMI 21. With better information I’ve now reset the intercept downwards to BMI 18.5. See the green “goals” box.

The bottom line answer to your question, therefore, is that I’ve learned from my mistakes. After 15 weeks I’m still (1) walking instead of running, (2) counting grams carb / fat / protein and calories for everything I will eat and drink at the beginning of the day instead of the end of the day, (3) checking my glucose before and after every meal, and (4) tracking weight / waist and fat / muscle percents on a daily basis.

Most of all, I’ve stopped rewarding any intermediate progress with off-diet food. Even when planning special event dinners, whether a whole lobster dipped in drawn butter, or a porterhouse steak and baked potato, it gets counted gram-for-gram, calorie-for-calorie before I make that reservation, and it is budgeted within the context of my nutrition allowance for that week. On those occasions, I routinely ask for a carry-out container as soon as I am served, and put half the meal aside before taking my first bite.

Thanks again for listening.

Hi Ramshakhan.

With apologies for perhaps confusing you, my last reply got off my own topic in answering a question on how I moved past yo-yo dieting and how I plan to continue that success. However, that reply still provided a quantified view of recent targets and results for body metrics, glucose readings, macro-nutrients, and calories.

Please don’t think I was requesting any dieting tips. I am trying to move forward on a quantified analysis and interpretation of impedance scale metrics. So any additional insight on the components (i.e., fat / muscle / other ratios) of my weight loss would be more helpful.

Presumably, the reduction of pounds of fat means reversal of prior fat cell hypertrophy by elimination of stored lipids within the cell. Does the reduction of pounds of “other” mean reversal of prior fat cell hyperplasia by reduction in the total number of fat cells including elimination of the remaining non-lipid fat cell material, surrounding extracellular support structures, blood supply, etc?

For context to this aspect of the topic, see

Hello Walter.
Really impressive story of self improvement on base of measurements!
Have you ever think about next step of investigation like:

  1. Exclude meat from ration, to use only fish and seafood
  2. Increase range of sport activities (cross fit, swimming, bicycle, …) to increase calories spends
  3. Extra program of walking 30-40 km per day for some period (camino de Santiago for example)

Thanks Sergey.

Keep in mind that my interest – and this topic – is regression analysis with Weight as the independent variable and %Fat, %Muscle% and %Other as the dependent variables. I’m still seeking an answer to the question on what Other actually consists of in body composition.

However, to answer your question, no, I really have no plans to investigate protein sources (meat vs. fish) or exercise modalities (walking vs. biking). The closest I come in that line of investigation is counting grams fat, protein, and carbs to calculate calorie intake, and estimating 100 calories per mile to calculate calorie expenditure. On your third point, I was walking an average of 10 miles per day several years ago, but have actually had better weight loss success by limiting snacks than by any analysis of nutrition or exercise.

In fact the only real benefit I see in any analysis is that it helps me avoid snacking. When I stopped tracking back in July, I started gaining weight, and I’m now back up to 160 pounds. That’s consistent with a study I read about which diets actually worked, that found the only diets that actually worked had only one thing in common – they required you to record EVERYTHING you eat.

Very interesting. Thanks for sharing! One pound of muscle is harder than a pound of body fat. Muscle loss often happens if you focus solely on calorie decrease. I’ve also got info about it at fine health page site. So everybody should aim not only on losing fat but also on gaining muscle.

You are welcome, Frank. In reviewing the entire topic above your reply, it appears that other newer information I’ve discovered is not included above.

For several months, I used a new technique instead of worrying about any discrepancy regarding “other” loss. I simply calculate my fat and muscle percent times weight to calculate the average pounds of fat and muscle lost per pound of weight lost. It turns out I could gain some muscle while exercising to avoid muscle loss. I could also reduce my waist about 0.2 inches per pound of weight loss.