I undertake fast on every Ekadashi and visit the temple. I get the Prasada (Anna Prasada) from the temple but I am in a predicament as to whether to partake of it or not, as on one hand the Lord and His Prasad are no different, and on the other hand, on Ekadashi day, one should abstain from eating rice. What should I do?

You can avoid the predicament by visiting any other Vishnu temple that does not serve ‘anna’ Prasad on Ekadashi day