Body fat and weighting.

[Kim]

I'm not quite sure where to put this so I'll start here.

To my delight I have started to lose a bit of the excess weight that I've put on since moving to Japan. So far I've lost 5 kilos but that will probably become quite a bit more over the next few weeks. Does anyone have any indication as to whether this will effect the amount of lead I need on my belt?

 

[Derek S]

I'm no expert, but I do know that fat floats more easily than muscle, so it would beg to reason that the leaner you are, the less lead you'd need.

 

[H2Andy]

hmmm... yes... muscle does weight more than fat... but do you have more of it
per square inch?

remember, it's how much water it displaces that matters, not how much it weights

(a battleship floats, but a stone sinks)

i'm just thinking outloud here. i think i agree with you, Derek

 

[Kim]

I'm no expert, but I do know that fat floats more easily than muscle, so it would beg to reason that the leaner you are, the less lead you'd need.

That's what I'm thinking too. Fat probably has more volume - therefore displacement. On the other hand losing 5 kilo in weight already means that your total weight in body + gear has already been reduced by the 5 - so I'm wondering if that would cancel it out or if further adjustments are in order. I'm curious if others that have lost weight have any comments from their experiences. (or if there is a body of knowledge on the subject)

 

[kent_1848]

I actually started working out, and lost a lot of fat, but gained muscle and weigh more this year than last. I'll let you know if I use more or less weight now. I was going to go diving next weekend, but now I have to wait until the 14th of May.

 

[spectrum]

remember, it's how much water it displaces that matters, not how much it weights

I thnk they both matter but are on opposite sides of the equation.

Loosing weight with an exercise program could result in smaller volume or less displacement.

Loosing weight with an exercise program that builds muscle will increase density, and reduce buoyancy per unit of water displaced.


Pete

 

[freediver]

Fat has a lower specific gravity than water. Muscle, bone and blood have higher a specific gravity than water. Therefore the fat has a tendency to float and the others tend to sink. So if the 5 kilos you have lost are fat loss and not muscle or fluid loss then, yes, you will require less lead on your belt. In fact a strength training program would be ideal since it promotes muscle gain and fat loss.

 

[neil]

Fat has a specific gravity of about .90 . That means, if I figure correctly (I am math-impaired), that for every ten lbs. (4.5 kilos) of fat you lose you get to drop about a pound off your weight belt. Not all that impressive for all the work it takes to lose it!

 

[immersed]

Your buoyancy is determined by two things: your weight and the volume of water you displace. Without knowing what the change in volume is, you can't definitively determine the effect of the weight loss.

For example, if after the 5 kilos the only outward change is a little thinning of your face, but no change in your waist, stomach, arms and legs, you'll likely actually have to add lead, because the displacement is essentially the same.

If the loss of the 5 kilos resulted in your losing 8 cm around your stomach, you'd be displacing significantly less water, meaning that the overall weight required would diminish as well. However, it could easily be a wash if the difference in the volume of water weighs around 5 kilos.

If you replaced the 5 kilos of fat with 5 kilos of muscle, you'd probably end up removing lead since the 5 kilos of muscle would displace less volume - however, it still depends on where the distribution is - if the fat didn't result in loss of centimeters somewhere, but the muscle increase caused cm gain (in your legs or arms, for example), you'd be displacing more volume and it could still be a wash.

So basically, three divers could lose 5 kilos of fat and one wind up adding lead, one end up remaining the same, and one could lose some lead.

Big congratulations, though - I'd love to lose 5 kilos!

 

[markfm]

If you lose 5 kg, hopefully there's more than just a bit of thinning in the face