Is it true a person loses a measurable amount of weight at point of death?

I have heard that supposedly people lose 21 grams at death. Some people believe that must be the weight of a human soul. I'm sure if I believe that or not.

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Answer:
A lot of people sh!t themselves right before entering the light.

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Answer:
How can that happen. I have seen a lot of people die in front of me (I'm a nurse not a hit man), I have never seen any loss of weight. Perhaps this appears so due to muscle relaxation and gravity effect on fluids

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Answer:
It's true that a lot of people defecate when they do die due to loss of muscle control, etc. Now, I don't really know how much (is any) weight is lost at point of death, though.