Does internal gas affect your weight?

17 January 2010


Cartoon bottom farting



What volume of gas does a person has to have to affect their own weight. Does having gas make you weigh more or less?


Diana - Well we have had a bit of a discussion about this and I think what it comes down to is what your farts are composed of! 

Of course, there is some hydrogen sulphide in there and occasionally some methane. I think it depends what kind of bacteria you have in your gut, but I think it was about five out of seven people will have methane produced in their farts. And, of course, methane is lighter than general gas (air) and therefore, you would think, if you have that in your gut, then it would make you a bit lighter.

But, of course, there's a question of pressure. So, if you have a lot of gas in your body that's under pressure, it would actually be denser than air and actually make you heavier. What do you think Dave?

Dave - Yeah. The things which could be in the gas, one is hydrogen which is one of the lightest gases we know of and that can be up to 50% of your flatulence, so if it's made mostly of hydrogen then it's going to be much less dense and the pressure change is going to be very, very small. So when you expel the gas, it could even make you heavier, because the hydrogen could've been acting a bit like a helium balloon in floating you ever so slightly.

Diana - I don't know if you could do a test by seeing if that gives a squeaky pop with a lighted splint?

Chris - Maybe Kitchen Science for the future!


thank you

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