In the competition, I lost 19 percent of my body weight
I Lost 50 Pounds on a 5:2 Fasting Diet
Dave Wentworth
5274

Strange KPI here, Dave. 
Usually you want to preserve lean mass, and get rid off FAT stored in bad places. Thus, you measure (or estimate) your “%bodyfat” and work on lowering it to healthy standards. What do you think?