The trypto is only part of it. Chances are you ate a large amount of carbs in you spuds and veggies and maybe even a glass of wine as a toast.
Both your insaline and shit I can't remember the word are spiked both are trying to digest the meal at the same time. this will cause you to crash.
That's why if you have a protein meal with very low carbs the body will process it much quicker and you don't crash.