Marvin, there are varying levels of ketosis. Even mild ketosis can allow the fat cells to release their contents.

As for Glenda's 4 hour window IF, that is actually a fairly common one, as is an 8 hour window. I use a 12/12, because that works best for my life right now.

IF is not only taking an entire day off from eating. It's limiting the number of hours that we take in food, during the day.

For MANY people, they start eating when they get up in the morning, and eat more or less constantly till they go to bed, roughly 16 to 17 hours later.

Of course, they're eating high carb foods, so their insulin levels are constantly elevated.