No need to clarify man, I don't mind such questions
For a number of reasons, mainly to remind us of the poor that some times can't even eat for whole days. It is even followed by an compulsory charity called Zakat Al Fitr, one half of the Zakat, (roughly translated to fast breaking alms) that those capable pay in a modest amount but if combined with all other people's it would be grand.
And btw, only the healthy adults are obliged to fast. Those with legit excuses either drop it completely, like children, of make up for it once they become able to, like women in their special day of the month.