i quite often get tired after eating, and i have for a long time, i was told it was something to do with the vegel nerve that runs up somewhere nr the stomach, it affects some ppl that way. it definately through eating too much with me, as if i even eat a teaspoon too much, i am actually ill. im lucky in that i dont work so have the luxury of lying down for a while after ive eaten, but when i was working i found it hard, and ive only ever eaten small portions, all my meals used to be eaten out of a small pasta bowl.