Srila Visnupriya Devi was the wife of Lord Caitanya before He took sannyasa. After His sannyasa, she lived a life of severe austerity. Every day, she would set aside one grain of rice for every round of the Hare Krsna mantra she chanted. At the end of the day she would cook and offer these few grains to Lord Caitanya, and that would be her meal. She is a manifestation of the internal energy of the Lord. (See the Bhaktivedanta purport to Srimad-Bhagavatam 4.23.20.)