I have heard you can be less strict with yourself if you IF and still gain many of the same health improvements as just being super strict but not IFing. Maybe even additional health improvements since you get the longevity benefits as well. But I don't think you'll get as many health improvements if your feasts are junk food. Mostly you can relax the carb restriction more if you IF.
I also think it's not right to compare the weight changes of men vs women in your above scenario as a sign of anything. Try it with two men and see if you see a similar pattern.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Current squat: 170 x 3. Current Deadlift: 220 x 3