I cannot comment on fat fast. But what works for me is this:

Dinner: 1. eat early.. 7PM
2. eat low/no-carb( 10G or less)
3. Low protien/no cheese stuff..
4. 2 Tbsp of olive oil ( 250 cal there)
Make your dinner 90% fat..
Next day morning, for sure I'm lighter..

neeam