Is there a Bad Side to Eating Healthy?

As a breastfeeding mom, I am really trying to focus in on my nutrition. I have been making a habit of reaching for junk food and telling myself "it is ok, because I need the extra calories for milk production." While my milk supply has been pretty good, I have also been feeling the effects of eating low nutrient foods. 
I am ready to get back to eating whole foods, but that looks a little different for the stage of life I am currently in. I talk about how I plan to get back on track and some of the effects someone may experience when deciding to have a healthier diet. Eating healthy is wonderful, but they may be a few weeks where you might not feel too great, at the beginning.