(Interestingly, note that Portuguese wine drinkers consume nearly twice as much as neighboring Spain!)
A fascinating science journal article looking at wine consumption in Portugal reports that the Portuguese mostly drink wine with meals, and in equal measure with lunch and dinner. The research also points out that they tend to drink the same amount whether it’s on weekdays or weekends.
So you can imagine, for newly arrived Americans, wine is wall-to-wall ubiquitous. And with its cheap prices and fine quality, it’s quite seductive. It flows so smoothly; at restaurants, the wine bottles are wrapped in cooler sleeves so you can’t see the amount in the bottle, hence it’s easy to keep pouring (or the wait staff pouring) and before you know it, the bottle is emptied by the end of the meal.