This day is a day of Fast (not eating between meals) and Abstinence (not eating meat). If this places a burden on you, then you are invited to excuse yourself.
Yes, I know. This is wrong on at least two counts. Is it really so difficult simply to teach what the Church teaches?
The law of fasting (at least in my Diocese and I think in the entire U.S.A.) is, of course, rather simple and straight forward:
On these two days of fast and abstinence [Ash Wednesday and Good Friday], only one full meatless meal is permitted. Two other meatless meals, sufficient to maintain strength may be taken according to each person's needs, but together these two should not equal a full meal. Eating between meals is not permitted, but liquids (including milk and fruit juices) are allowed.
To disregard completely the law fast and abstinence is seriously sinful.
Simple enough, yes? Yes.
It is not a matter of whether the obligation to fast places "a burden on you." It is supposed to place a burden on you. That's why we call it penance.
The bulletin announcement should have something like, "If this places on great burden on you..." But that is why the two smaller meals "may be taken according to each person's needs."
The idea is not that everyone takes two smaller meals on these days, but only those who need. Indeed, most people should only take one meal (that's a penance).
Take me, for example. The medicine that I take for my arthritis must be taken with food and I take if four times a day by doctor's order: with breakfast, with lunch, with supper and before bed.
Medically, it would not be prudent for me to take the medicine throughout the day and only eat one meal as the medicine - without food - can do horribly things to my stomach (apparently). It would also not be prudent for me not to take the medicine on these days and fast; a great penance that might be, yes, but I might not be able to carry out the duties required of me.
But even in this situation - and many others similar and far more serious - one is never "invited to excuse yourself." Holy Mother Church excuses - we would say dispenses - you.
You can only excuse yourself from something that you say that you will do. You can only ask to be excused from what someone else requires of you. And in this case you don't even have to ask.
I hope that clears things up a bit.