Grace, welcome!
I know it well. You start the day off right, but by mid-afternoon, you're tired and a little cranky, and the easiest solution seems to be to eat.
Why don't you try "being good to yourself" around that time. Have some healthy snacks on hand (ie: some precut veggies and a nice dip. Maybe some protein... a spoonful of peanut butter to charge your batteries...), and take a little time for yourself. Curl up with a book or a magazine... even if it's only for 20 minutes. Do something for YOU.
I love your quote, by the way... it's one of my favourites.