Something is suspicious here. He lost 125kg of which roughly a third might be fat and two thirds water. A gram of fat burns into 9 kcal. He fasted 382 days. This means that he burned about 980 kcal per day which sounds very low even for someone that is not doing any exercise
I think the fat cells in your body have a ratio skewed much more towards fat, and are an exception to the "your body is 2/3rds water" rule-of-thumb.
I suspect this is the answer.