Below is my weight loss for the last 21 days. The spikes are days that I ate what I wanted and not worry about the diet. You can see how after the spikes my weight dropped back to near my loss level. This seems to work with IFing. My first goal is around 175lbs. I should be there by about day 40+.
I don't stress if I go out and eat not so healthy or too much. I try to keep my eye on the long term goal. For me weighing every day helps me know how to tweak my eating. I can keep a better handle on it that way.
Good luck to others that are trying this type of eating.