Calculating Fat lbs lost

SueM86

Hi there,

Can anyone tell me if my assumptions are correct in the following calculation.

When I started trying to get back into keto I weighed myself and took my body fat % (via my scales) and measured 4 parts of my body. I'm around 5 weeks in and have taken my measurements every week.

So far I have lost 10lbs and around 2.8% body fat (calculated by simply subtracting today's fat % from the starting %) and inches from everywhere.

If I take my starting weight in lbs and multiply it by the fat % at that time I can then come up with a figure for how many lbs of fat I was carrying at the start. Then if I do the same with today's weight and fat % I can see that the total lbs of fat has gone down (obviously!)

So my question is - based on this calculation, of the 10lbs of scale weight that I've lost the fat content comes to 9.95lbs - meaning I've lost practically only fat and no lean muscle. Can this be right or have I missed something? I have been doing some exercise over the weeks but not that much as I've been nursing a couple of injuries. So I've cycled a few times (around 15 - 20 miles per time at an average speed of 10-12mph) and I've done a few body pump classes (weight lifting) but kept the weights very light.

I'd like to think that I"m burning fat and not muscle. To be honest I would have hoped to have seen a more dramatic scale drop and more inches lost all over but that's just because I"m impatient! My ultimate goal weight is around 48lbs less than I am today - and I'd like to drop another 2 - 3 dress sizes - so the sensible part of me keeps trying to remind myself that everything is going in the right direction. In total I've lost 3.5" from my waist, 2.5" from my hips and 2" from under my bust so I know that it's working - but I can't get into my head that the number on the scale is the least important - and I'd still like it to be moving more quickly!

Do you think I"m right in thinking the weight I've lost is fat burned? It's so hard to know if you're doing the right thing and sometimes it gets very boring trying to stick to a maximum of 25g of carbs a day - but if it's working to burn fat and not muscle then that will give me the motivation to keep with it.

Any ideas, comments, advice?

Thanks

yarwell

Guessing some numbers :-

160 lbs 42.8% body fat gives 68.48 lbs of fat
150 lbs 40% body fat gives 60 lbs fat

8.48 lost.

84.8% of loss is fat. It can be as low as 60-70%. Losing only fat is a challenge, and well done if you succeeded.

Leonidas_meets_Spartacus

hard to tell, get a bod pod test and see how closely they match up with your measurements and calculations. If you are losing inches, its most likely fat.

SueM86

I guess the proof will be in the pudding in the long run! Lost another couple of pounds this week but fat % stayed the same so only around half of the scale weight loss this week was fat - which is probably a more realistic representation. I think maybe last week's numbers were a slight anomaly - however inches also lost so happy that everything seems to be going in the same direction and long may that continue. Going to be a tough week next week as I'm going on holiday but I shall endeavour to limit the damage as much as I can and then return 100% to keto once I'm back home again.

Thanks for the comments guys.

deansdad101

I guess the proof will be in the pudding in the long run! Lost another couple of pounds this week but fat % stayed the same so only around half of the scale weight loss this week was fat
(snipped)

Thanks for the comments guys.

Sue;

I'm as much of a numbers "wonk" as the next guy (some would say *much* more than just "as much..."), but.....
5 x 2 = 10.....always is and always will be as long as 5 is *exactly* 5 (not a "guesstimate" that might be 4.8 or 5.2).

If what you "think" is a 5 is really 5.2, then 5 (sort of, but really 5.2) X 2 = 10.4 not 10

Overly simplistic, of course, but the point is ALL of this stuff is based on "guesses multiplied by other guesses" and while your calculator will happily give you answers calculated out to the 10th decimal place, if what you enter is a "guess" and you multiply it by another guess the result will always be a guess X another guess - raised to the next order of magnitude.

You began the thread by saying "...body fat reported by my scale..." (or words to that effect).
Do you KNOW which set of algorithms the scale is using to *calculate* BF?
Do you KNOW that when the scale reports 126.8 it's not actually 126.4?
(likely not but neither do 99% of most people)

The googlemachine will be more than willing to offer up 10's (if not 100's) of BF "calculators".
Pick out 3 or 4 and plug the exact same numbers (sex, age, waist, hips, neck, whatever) into all 4 and you'll likely get results that vary by 4-5% - how can that be if you "know" that yours is *exactly* 2x.x% ???

Which one is "right"?

It's ALL a guess (or, more charitably put), a "best estimate" - based on averages, assumptions, and how close YOU are to the top of any number of bell curves used as the basis to create the various algorithms.

24.49768459% SOUNDS so much more precise than (when rounded) to 24% until you compare it to the results of another calculator (using different algos) that says 21%.....now what?

It's ALL a guess, at least until you get to the really advanced and highly technical "instruments" that actually are capable of measuring (as opposed to calculating) BF (although even many of those still rely to some degree on calculations).

One simply cannot obtain the same degree of accuracy from a $5 set of calipers, a free, online calculator, or even a $300 scale, as they might from a $5000 trip to your local metabolic chamber.

So, my advice (FWIW), back it off a few (maybe more than a few) decimal places.

You've expressed your frustration (or dissatisfaction) with results of ~2#/week and "...lost another couple pounds this week..."

If anything, 2#/wk is TOO high a rate (long term) and likely unsustainable.
It is, however, not unusual either for those just starting on the journey, or those making a major change (ie used to be Low Cal/Low Fat, now I'm VLCHF).
Usually attributable to either "water weight" or just "shocking" the bod into major physiological changes (as keto does), and a whole new way utilizing those energy cals.

It (weight loss/wk) WILL (or, should IMO) slow down as time goes on so steel yourself for that which is probably inevitable - it's NOT your "fault", you can't "fix it" by reducing cal intake to unhealthy levels, and it's PERFECTLY NORMAL so just deal with it and know that you are doing the "right" thing - despite what any scale or calculator says on any given day.

Focus on the TRENDS - long term (and the longer the better), the AVERAGES, and the very best "scale" of all - YOUR MIRROR.