Calories matter, quality of food matters. Eating 100 calories of candy vs 100 calories of broccoli has completely different responses from the body. One will spike insulin, one will have little effect. I’ll let you figure out which is which.
Start with minimal restrictions on what u eat - but make the immediate meal before each fast begins a high-fiber / veggie one so ur hunger can be suppressed longer . As long as u r doing at least 16 hours of fasting then your insulin levels will drift down 12-hours after last meal and you will have a natural fat burn