Here's a thread from last month regarding breastfeeding:
You'll find a brief mention of my personal experience with it.
http://community.myfitnesspal.com/en/discussion/10494283/low-carb-while-breastfeeding#latest





From what I've read, the mother's macro percentages are irrelevant. Your body will take from you what it takes to make the milk. Every ounce. The percentage of particular fats will differ slightly, based on your kind of diet (healthy fats vs. unhealthy fats), but your body will produce perfect milk. With too little calorie intake of the mother, supply might be in jeopardy though, in addition to the mother's health if her diet is poor and/or she is nutrient deficient. But as long as your electrolytes are in balance, you are properly hydrated, and you are eating enough calories, the milk will be fine regardless of whether you are eating low or high fat, or low or high carb. They've done studies in 3rd world countries in which nutrition for the mother is sketchy at best, and they show that milk composition is still fine. Nature is smart.

Breastfeeding during the first 6 months is not the time to actively try to lose weight. However, considering your supply is well established, you should have no trouble with that carb level.

I'm pretty sure that my carbs were around 50g. I wasn't really tracking that diligently, so I have no idea what my macros looked like. I never had a supply dip, not even when I was sick. Not even when I was losing weight. I nursed my youngest (the longest any of mine nursed) until he was 21 mo when he decided he was done. He is now a brilliant evil genius who just turned 6.

I suggest you read around on a certain site if you are interested in nerding out on the subject. She's got comprehensive EVERYTHING regarding breastfeeding. http://kellymom.com