As a former marathon, and ultra marathon, runner I tried, seemingly, every diet plan known to human kind: three day hot dog diet, four day ice cream diet, five day potato diet, fasting, seven day soup diet to name a few and I hated them all by the last day of their period. The one diet that worked the best, and every time, was the Mayo Clinic diet which guaranteed a loss of twenty pounds in two weeks. I was pretty streamlined from all of my running so I did not think that twenty pounds was possible. In twenty five years of running I was able to lose twenty pounds before each race and the diet was reasonable (didn't starve me). I remember that every breakfast was half a grapefruit, piece of toast and a cup of coffee/tea, lunches were some what sparse, and dinners were all you can eat of different proteins every night (steal, fish, pork, hamburger, etc).