They did a Lenten fast once a week, which is not usually the same as abstaining from food. From the article, it sounds like they were eating but not eating meat. However, note that fish is not considered meat for the purposes of Lenten fasting.
It is the same today... Catholics in my pueblo do not eat carne on Fridays (during Lent) which is to say no air breathing animal. Tuna fish salad is a very popular meal on Fridays if you have a house full of Catholics during Lent.