Have heard that for certain tithi-s partaking of rice is prohibited during day times and on certain tithi-s it is prohibited during night times. On days when rice is prohibited during day times, can we partake rice at night times? Some say these regulations are applicable only during Krishna Paksham. Are there any details on this?

Partaking food is prohibited during daytimes on Krishna Paksha Ashtami and Caturdashi days; food is prohibited during night times on Paurnami and Amavasyai days; this is an authoritative orthodoxy; some follow this even to this day; while following this practice, for Krishna Paksha Ashtami and Caturdashi observances, if there are no other malefic influences for those tithi-s, one can partake food during night times on these days.