The disadvantages are that every day at lunch time you'll feel guilty for not working out, unless you are working out, in which case you'll feel good about yourself... except when you are hungry, or startling yourself by seeing your own fat, naked self in passing in front of the mirror in the locker room.
I'm sorry if that conjured up any images of flabby, pasty, naked, balding middle managers. But not so sorry that I won't help the image along with a little bonus verbage ("hey, I used the words 'pasty' and 'naked' in the same sentence!")
The point of this little ramble is that I got so sick of passing pasty, flabby naked men in the mirror that I decided to diet. If the next few entrys sound grumpy, it's because I'm not getting enough Nestlé Quik (now "Nesquik" for reasons beyond the ken of mere middle managers [or cartoonists]) in my bloodstream each afternoon.