“三十里的莜面， 四十里的糕， 二十里的饸饹饿断腰。”
This is what I heard of in Yu County, Zhangjiakou last week when I took my students there to do the public welfare activities. It took several times to repeat before I could catch the very exact character because people speak with their own strong Yu County accent.
What does it mean? I raised my question for the further and better understanding.I got the rough meaning:
“After having a big bowl of oat noodles, you could cover fifteen kilometres without feeling hungry.”
“Take a big block of millet pastry, and you can travel a particular distance of twenty kilometres.”
“If you have enough buckwheat noodles, you starve to death after ten kilometres.”
The above talks about the special hard plants living in Zhangjiakou. And they make it slow to digest, keeping you feeling full longer.