Calories, Work, Fat, and Mt Dew

T

Trevor

Registered Member
I'm not a chemist, and I am not exactly sure how energy is stored in ATP and fat.

Here's my thoughts.

If you lift a 1kg object 1 m, the work done is

W=f*d=mgh=9.8 joules

1 calorie = 4.18 joules, so
1 can of mountain dew = 170 calories, but i recall that these are actually kilocalories (right?),
so 1 can of mountain dew = 170*1000 = 170,000 real calories, or 710600 joules/dew.

9.8 joules/lift,

710600/9.8 = 72,510 lifts per dew.

So I would have to lift 1 kg 1 meter in the air 72,510 times to burn off the calories from 1 can of dew?

That seems a little off. Am I missing something? I wonder how inefficiency figures into this.

On to biology, which I am less familiar with:
ATP stores energy for our muscles. At what point is fat tapped for energy, to be transferred to ATP?
It seems like the core of a fat-burning work-out is to deplete the supplies of ATP such that fat reserves are used.


Can some more knowledgeable person set me straight on this subject?
 
ATP is more of a unit of energy, rather than storage. It is how energy is transferred from place to place, due to the high energy in the bond between the secong and third phosphate (they are both negative, and are side-by-side). Energy is mostly stored as glycogen, which is a polymer of glucose, in the liver and skeletal muscle tissue. However, you can only store so much energy there, and then it's on to fat, which actually stores more energy per molecule than glycogen. However, it is a resource that is harder to retrieve.

So, once you have used up all your glycogen stores, you begin to break down fat, which releases a lot of energy. Then it's on to breaking down muscle tissue, but once you're at this point, it's likely a little too late, and you will starve to death.
 
Originally posted by Idle Mind
ATP is more of a unit of energy, rather than storage. It is how energy is transferred from place to place, due to the high energy in the bond between the secong and third phosphate (they are both negative, and are side-by-side). Energy is mostly stored as glycogen, which is a polymer of glucose, in the liver and skeletal muscle tissue. However, you can only store so much energy there, and then it's on to fat, which actually stores more energy per molecule than glycogen. However, it is a resource that is harder to retrieve.

So, once you have used up all your glycogen stores, you begin to break down fat, which releases a lot of energy. Then it's on to breaking down muscle tissue, but once you're at this point, it's likely a little too late, and you will starve to death.
Click to expand...

Is it a sudden transition where I start burning fat, right when I pretty much run out of glycogen?

Is there a way to tell I am at this point? How long does it take to reach this point?

What is the best way to reach this point where the glygogen is depleated? Just doing work? Cardiovascular work outs or muscle weight-lifting work outs?
 
I'm not exactly sure of the kinetics of it, but I would imagine there is a lag between the glycogen burning and the fat breakdown. You will breakdown the glycogen releasing energy. Once the energy from that catabolism is used, or low, you will begin to breakdown fat.

There really isn't a way to tell, since you are using energy in both cases. How long it takes will depend on your glycogen stores, and the amount of work you are doing.

I would say that the best way to reach that point is cardiovascular related exercise.
 
I think the problem here is that your not taking into account the server mechanical and biological inefficiencies in doing physical work.
 
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