Why? How?

I read David Dust's blog this morning (as I do every morning) and he was complaining (bitching) about his weight (post here). It is funny because I had been mouthing the same words to myself when I weighed in this morning. How is it possible that I have gained back almost all of the weight that I lost in the last few months? And why does it seem so difficult to lose the weight but gaining it back is a breeze. I am frustrated with myself, my body, my age and hell even my husband at this point.