My husband posed this question to me today ….and I said ‘presumably when you go to the toilet’?
But it’s not so….mostly its by ….breathing out …
The sad news is that you can’t lose weight only by breathing out (I got all excited for a few minutes at that possibility)
You have to actually burn off the fat first….so its off my bum and into the Nikes…oh dear
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Healthy Harriet 
Well, you just answered one of my big life questions–and here I’ve been trying to poop it out like crazy! 🙂
lol!