Breastfeeding and running

Can't answer the breast feeding part.

However - take a look at the foods you are eating - do you use low fat/low calorie versions? I find a lot of people with this comaont are eating low fat yogurt, skim milk, Etc. If so switched them out for full fat.
Other options are adding nuts and nut butters and avocado - nutrient dense and calorie dense.
Adding olive oil can also bump up calories.
You can also try different cuts of meat that aren't as lean and eat salmon instead of white fish.

Healthy doesn't necessary mean low calorie but a lot of people tend to lean that way when dieting. And having treats to meet your calorie goal isn't a bad thing, especially if the rest of your food is nutrient dense.

I do not run but I do other cardio and I am breastfeeding. I am trying to lose weight though, but I have to eat back my exercise calories and eat more than usual to keep up milk supply. I have supply issues though from bad latch. I eat lots of nut butters, oils, and butter to up my calories.

Wow how do you pump 60 oz a day!! I'm happy when I find the time to pump 6 oz!!

I'm exclusively pumping because my baby has a posterior tongue tie and I didn't want to get it clipped. I had to pump with my last baby as well, who had an overly strong tongue thrust reflex. I developed an over supply quickly last time from pumping every two hours. Eventually I was up to 60oz. This time it only took me a week and a half to get to that point. It's just what happens to me, I don't really understand how or why. With my first baby I had almost no milk at all.

Yes it's possible. I breastfed my daughter for a year and ran a marathon when she was 6 months, so I was training that whole time. As long as you stay hydrated and eat enough calories, supply shouldn't be an issue. Good high calorie foods to eat would be nuts, nut butters, avacado, dried fruit, granola, cheese, quinoa. Good luck!