It should help. 18:6 would work a little faster.
Not a doctor but…
If you’re breastfeeding you may want to wait or be conservative on how long you fast. Fasting can signal to your body that it needs to stop production. And if you can, you probably should breastfeed. It’s better for baby (research backs this up) and much cheaper than formula, especially if you find you need specialty stuff like nutramigen. Added bonus is it can help bring your weight down too, it takes a lot of calories to produce.