I spent a week in my early 20s eating nothing but doughnuts to spite my aunt who had ranted about how it was "impossible" eat doughnuts and lose weight. I was limited to 4-5 doughnuts a day to keep the calories low enough to noticably lose weight over the week. And I let myself have black coffee when I started to feel hungry. I had spite and youth to keep me going, I cannot imagine voluntarily doing this diet unless you're an alcoholic who refuses to cut back on your bottle-a-day habit and you need to lose a bunch of weight fast.