I think Floyd Mantis used to opt for the 3-day-fasting technique in order to hit race weight in the run up to grand tours. No pissing about with protracted diets.
I'd imagine all you can do for exercise is pootle along at 12mph/on the turbo, right at the bottom end of your fat-burning zone. TBH, I'd definitely not do it on the road, as I doubt my mental faculties would be all there.
i doubt my mental faculties at the best of times...
i doubt my mental faculties at the best of times...