Halp pls

I have a bet with my dad: in 8 weeks I have to have less bodyfat (from about 23% down to 15%) than he's got. I am already going full ketosis, what else can I do?
If I loose, I'll have to eat some super disgusting shit from our local asian food store.

Do a couple of week long water fasts

look up pro-ana diets mook

Sounds like typical dead bants to me, asian food dog meat dead sort of thing

Do 2 water fasts of approx. 4 weeks each.

Kill your father and assume the role of dominant male in your household.

I wanted to do that for the last 3 days.

I need him for income though...
will I loose muscle in the process?

3 days is for chumps do a week long fast on week 3 and maybe week 7 if you're not at your goal by then

Isn't that a pretty unhealthy thing combined with low carb?