Why didn't the irish eat beans?

They ate their enemies.

Lady Darko

I guarantee, Irish people eat beans.  We eat as healthy a diet as we can.  Anything that will keep your insides clean and give you energy for rough work is well in order.

About the one thing you DON'T want is too much meat or not enough fat, hopefully lard or bacon fat used in cooking.  Mexican rancheros learned that lesson very quickly and we follow suit.  It is just the smart thing to do.

We'll start the day with 2-3 eggs, beans, fruit juice, a little bit of milk, and loads of buttered corn tortillas.  Your system will synthesize just about everything you need from that.  Breakfast is the big meal.  Pile on the calories and then kick back about ten minutes before you start work to get your stomach empty and everything into your intestines.  Then hit the latrine.

Lunch might be the same but only half as much food and three times as much water.  Then a short nap. 

Dinner might be the same as lunch.  Spare the tequila, pour the cervesa.

You'd be surprised how many tough Scotch-Irish there are in the rodeo.  We eat what we should. 

It's just personal habit.Maybe you just see someone don't but some do.

You say, "why didn't"   Do you mean in the early days of Irish History?  If so, the answer could be that they did not grow them or could not grow them.