How is my Math regarding bodyfat % (any gurus plz help)

[Balloon]

Ok,
Take for example a 200lb guy at 20% bodyfat.

20% of 200lb = 40 lbs of fat

So the 200lb guy has 40lb of bodyfat.

If he wanted to get to 10% bodyfat, would he simply have to lose 20 lbs ( 20%=40lb so 10%=20lb)

So if he cut from 200 to around 180...then he should have gone from 20%bf to 10%bf

Please help me understand this

[tbombz]

okay if by miracle you lost pure body fat and  no muscle then youd be 160 with 20 lbs of fat and 20/180= 9 so no yuoud be 9 % bf

[Balloon]

okay if by miracle you lost pure body fat and  no muscle then youd be 160 with 20 lbs of fat and 20/180= 9 so no yuoud be 9 % bf

How would he be 160? 
If he is currently 200 with 20% bodyfat (40lbs of fat)
and cuts 10% of fat (20lbs of fat)
then he would be 180 right? at 10% bodyfat..


I know it is unlikely he would lose pure fat...

[Bluto]

with the name "Balloon" I take it youre quite desperate to lose weight huh arnt you son

I bet youre pretty tired when people say "your full of hot air" and joke about you arnt you son

[Tapeworm]

A man with 40 lbs of fat and 160 lbs of lean mass, 40/200 = 20%bf.

A man with 20 lbs of fat and 160 lbs of lean mass, 20/180 = 11.111%bf.

A man with 17.7777777777777777 lbs of fat and 160 lbs of lean mass, 17.777/177.777 = 10%bf.

To find your goal weight if you wanted to be 10%bf, multiply your lean lbs times .111111111111111, and add that to your lean weight.  This assumes you live in a perfect world where your muscle mass remains constant and you only lose fat when dieting.

[#1 Klaus fan]

Got me thinking for a while but if you just calculate the lean body mass like Tapeworm did itīs easy.

[Tapeworm]

Unless you live on a beach, 10% is pretty lean for a natural.  Most guys (myself included) won't make it under 10% simply because they get a lot smaller and it sucks feeling small.  Most lifters are closer to 20% because they want mass.  Juicers, the genetically gifted, and guys with a lot of years in the gym will hold some size.  The rest of us will look conditioned but puny by bodybuilding standards.

[tbombz]

Unless you live on a beach, 10% is pretty lean for a natural.  Most guys (myself included) won't make it under 10% simply because they get a lot smaller and it sucks feeling small.  Most lifters are closer to 20% because they want mass.  Juicers, the genetically gifted, and guys with a lot of years in the gym will hold some size.  The rest of us will look conditioned but puny by bodybuilding standards.

4real

[Tapeworm]

Got me thinking for a while but if you just calculate the lean body mass like Tapeworm did itīs easy.

Yes.  I am a 'bodybuilding guru.'    It says so on my tshirt.  For some reason people laugh when I wear it.

4real

The worst part of dieting for me is between 12-16% (I'm guessing).  The abs are starting to appear but are nothing to brag about, and it's nice to see definition coming in, but everything is shrinking, shirts getting looser, etc.  I guess I'm not losing muscle because my lifts are hanging in there.  It's nice being lean at the beach, but I find myself longing for the days of eating garbage and benching a new PR and thinking it felt pretty light.  Of course, talk to me after Christmas and I'll tell you fat sucks and I miss being lean & mean.

Anyway, I reckon most guys diet for a couple weeks and their body lets go of fat where it's inefficient to store it first - arms, shoulders, chest, etc - and doesn't lose much off the gut and lower back where the body can carry it easily, so they actually look worse after dieting for a short time.  So they just give up.

[240 is Back]

Unless you live on a beach, 10% is pretty lean for a natural.  Most guys (myself included) won't make it under 10% simply because they get a lot smaller and it sucks feeling small.  Most lifters are closer to 20% because they want mass.  Juicers, the genetically gifted, and guys with a lot of years in the gym will hold some size.  The rest of us will look conditioned but puny by bodybuilding standards.

+ 1

[disco_stu]

Ok,
Take for example a 200lb guy at 20% bodyfat.

20% of 200lb = 40 lbs of fat

So the 200lb guy has 40lb of bodyfat.

If he wanted to get to 10% bodyfat, would he simply have to lose 20 lbs ( 20%=40lb so 10%=20lb)

So if he cut from 200 to around 180...then he should have gone from 20%bf to 10%bf

Please help me understand this

no. none of this nor the replies are correct.

what you've excluded is the weight of a person's bones, organs and so on.

then you have water also.

about 13% of the bodyweight is bones and the water in the bones.

then there's another 5% for organs...and about 10% more of water that is outside of the bones..

so for a 200lb person about 60lb is not muscle and fat.

So, if you measure 10% bfat, then for the 200lb person that means 200lb-60lb=140lb x 0.1 = 14lb fat.

so the person's lean mass is 186lb but amount of muscle is 126lb.

[disco_stu]

Ok,
Take for example a 200lb guy at 20% bodyfat.

20% of 200lb = 40 lbs of fat

So the 200lb guy has 40lb of bodyfat.

If he wanted to get to 10% bodyfat, would he simply have to lose 20 lbs ( 20%=40lb so 10%=20lb)

So if he cut from 200 to around 180...then he should have gone from 20%bf to 10%bf

Please help me understand this

if he is 20% BFat as measured then from his approx 140lb of weight that isnt bone etc..he is holding 28lb of fat.

to get to 10% bfat he needs to be holding 14lb of fat- in total.

so the target weight would be 186lb.

not 180lb.

[bodybuilder1234]

10% is the lowest I ever reached and even that was a nightmare