I'm not breastfeeding anymore, but as a general nutritional guide, you're often hungry because your body is craving nutrients. That's why people can be hungry shortly after eating something junky, it didn't give the body anything that it was looking for, so it keeps on looking, hence you continue on being hungry.
I find this true with bouts of sleepyness too. I find that I'm often dragging mid-day and if I eat something very nutritious I pick right up. That's evidence to me that my body was calling for what it needed.
I cook a lot, at least two meals a day -- so we have lots of nutritional leftovers around. Honestly, cooking a lot, and cooking healthy is the only sure-fire way I know to keep weight at a stable and healthy average.
