Is too much urbanization a bad thing?

Recently my capital Lombardy has become the biggest city in Europe and a big urban hub, and I've had a bunch of extra cash so my other cities have been growing fast too. I'm a bit worried though that there won't be enough food soon, since I've seen some posts about famine getting really bad. Already like 60 to 70 of extra food has been used. Should I slow down urban growth?