Is there a specific word or phrase for the drowsiness one might feel soon after a heavy lunch?

Question

After a lunch, especially a nutritionally dense one, one might drift off into a drowsy state, sort of a "I sure could use a nap" feel, likely due to the breaking down of the foods in the digestive tract.

Is there a specific, common word or phrase for that drowsy feel/condition?

Example of a relatively dense meal:

• First course: artichoke (2 helpings)

• Main course: steam cooked blood sausage (2 helpings); garlic/parsley flavored shiitake mushrooms and potatoes cooked in duck fat (2 helpings)

• A portion of camembert accompanied by a half glass of red wine

• Dessert: a handful of walnuts; a square of dark chocolate

• Hot beverage: green tea to wash down the whole thing

Answer 1

This is sometimes referred to as a 'Postprandial dip'!

In medicine and specifically endocrinology, postprandial dip is a term used to refer to mild hypoglycemia occurring after ingestion of a heavy meal.

www.wikipedia.org

It can also be called the 'afternoon slump' or 'post lunch dip'

Answer 2

The Itis is what it is called!

Postprandial somnolence (colloquially known as a food coma, carb coma, or in the African-American community the itis) is a normal state of drowsiness or lassitude following a meal.

[Wikipedia]

Perhaps derived from the suffix "-itis" which is a suffix largely associated with illness and diseases.

Also, as @jera suggests, food coma seems to be a widely used and recognized term.

a state of sleep or extreme lethargy induced by the consumption of a large amount of food.

[Google Definition]