All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Distributing sweets amongst your colleagues at work is permissible in itself and there is nothing wrong with it as long as there is no external factor that renders it prohibited. However, distributing sweets does not substitute the Islamic Waleemah (i.e. marriage banquet) which is a confirmed Sunnah for the one who is able to do it, for the Prophet, sallallaahu ‘alayhi wa sallam, said: “Give a Waleemah even if it is with just one sheep.”
For more benefit, kindly refer to Fataawa 85394 and 82622.
It is worth noting here that there is nothing wrong with giving food to the non-Muslims and that a man should be cautious in dealing with non-Mahram women. It is not permissible to mix with them at work or in any other place if this leads to something prohibited such as looking at women who do not abide by Hijab or being in seclusion with them or speaking with them without a real need to do that.
Allaah Knows best.