There is a concept in Christianity that I think the West has forgotten to the point that it makes no sense to do it anymore: the concept of the Lenten Fast. For those of us who follow the traditional Christian calendar, there is a season of Lent once a year that leads up to the joy of Easter. This is usually a seasonal of austerity and penitence so as to give Easter more meaning when it arrives.
There are three elements that need to be considered, the fast, the abstinence, and the disciple. I think people confuse these. What sort of rankles me these days is people giving up something (chocolate, booze, whatever) and calling it a fast. The reasoning they say is "because Sundays are not fast days, so on Sunday I can indulge." I hate to burst your bubble, folks, but that is not a fast. That is just abstaining for 6 days a week. In fact, you are missing the entire point if you think that is what a fast is. Dare I even say that you are wasting your time.
A fast is in a way a switch. You give up something, say dinner, and during the time you would normally be eating, you pray or do something like work in a food pantry or what not. You seek God through the fast, its not just abstaining from something.
And about this notion of Sundays are not a fast day. Well, that is true, but since you are not really fasting, you are giving something up, usually something you should not be into anyway. Since it is not a fast, Sundays do count. Giving something up is more like a discipline, something you are doing for yourself. Its like the Alleuias. We don't not say them 6 days a week and then on Sunday say them because Sundays are not a part of Lent. Gorging yourself on Sundays for something that is not a fast is not what Lent is about, folks.