What exactly is meant by food coma?

Tryptophans in turkey can bring on "food coma," as well, which is why I think Diane mentioned Thanksgiving, LOL!

Ah, yes. The food coma.

It's that listless, slightly uncomfortable, too-full feeling that comes when we've eaten too much food. It's often accompanied by the urgent need to unbutton our waistband and lie on the couch, napping in front of The Masters golf tournament, until some of our food is digested and we feel close to normal again.

(And if you substitute NFL for the Masters, we could be talking about Thanksgiving as well.)

What happens to cause all this?

One primary thing: You've eaten more food than usual -- a lot of it on the carbohydrate side of the scale -- and in order to digest it all, your blood, hormonal and amino acid systems all must respond. If you ate too many carbs, your meal ended up being high on the glycemic index, and your blood sugar reacts accordingly. There's an actual big official name for a food coma: Postprandial Somnolence.

I imagine that at brunch, your sister-in-law was trying to eating smaller portions and trying to balance the amount of protein and carbs. She might also have avoided wine or dessert. Am I close?

And more importantly, did she succeed?