It’s a while since I finished all my buildings but I think the only way is to click on any building and see what it can convert to and consider if you can take a break from it.
I also store loads of ham in four tc20s.
Nowadays when I’m short of food I just don’t log in for 36 hours then collect a ton of ham and iron but that doesn’t help you much I guess.
I’m sure someone will be more helpful than me. Good luck
