Niyah (Intention) to please Allah (swt) is very important for a person who Fasts and all other deeds!

Narrated 'Umar bin Al-Khattab: I heard Allah's Apostle (Sallallähu Alaihi Wa sallam) saying, "The reward of deeds depends upon the Intentions and every person will get the reward according to what he has intended. So whoever emigrated for worldly benefits or for a woman to marry, his emigration was for what he emigrated for."
(Sahih Bukhari, Book #1, Hadith #1)

Ramadhan A Date With Dr Zakiir.