The OP is incorrect. Protein takes longer to digest than vegetables, fat takes longer to process than sugars. God didn't give us food discretely separated by digestion time.
Our bodies are quite able to process the foods we eat... in combination. What we call "fruits" and "vegetables" is all mixed anyway. Many so-called "vegetables" are actually fruits - tomatoes, peppers, cucumbers, squashes: all technically "fruit".
I'm certainly not going to pick the bits of spinach out of my pasta sauce to eat separately from the pureed tomato and pepper chunks.