How can I track breastfeeding on this app?

Yeah this is what I would do using the app.

Go to add new exercise.
Then Cardio
Then My Exercises
Then Create a New Exercise

Now, the tricky bit is that what you will use is depending on how much your little one is taking so its really difficult to be exact (unless you express I guess). Anyway, then it might depend on number of feeds as well. But, a little reading suggests you could be using anywhere from 400 - 700 calories per day (wow!). I think it if it was me (ok I know I know), then I would perhaps make the exercise that you create burn an average of 500 cals. Then you could add it at the end of the day and base it one what kind of day you thought you had? If the little one you felt had taken a lot or not as much that day?

I've also read that 1oz is around 20 calories. So if you produced 20oz over a day that would be 400 cals.

Sorry not an exact answer but hopefully gives you an idea.

For some reason when you search breastfeeding and add the negative number it doesn't work anymore. I agree with creating your own exercise!