I want to make sure I do it right, as I read alternate day IF caused resistant visceral fat, but wasn’t sure if 20:4 would cause the same resistance.
No.
Changing your metabolism, despite what the pop media says, is actually really hard. You might go into “starvation mode” if you don’t eat for days… not for a few hours a day. We are persistance hunters and scavengers… we evolved to go a long time without food and then feast.
Keeping your metabolism high is fairly easy. Do anything physical. This doesn’t have to be a 2-hour Crossfit routine, just taking a walk is enough to keep your metabolism up.
As far as I understand it, as long as your insulin levels are low, your body will take from its stores to use what it needs.
If your insulin levels are high due to eating a carb heavy diet, your body doesn’t have the ability to access its stores and therefor, has to gear back it’s metabolism after a period of time.