I checked this article, and it provides some data on breast milk volume and composition. (scienceofmom.com)
These symptoms are caused by a sudden increase in breast milk volume as well as an increase of blood and other fluids entering the breast ducts to assist the glands with making milk. (justbreastfeeding.com)
Breast milk volume almost doubled in the date - eating group as compared to the control group. (lactationlab.com)