Nairobi (AFP) - President Barack Obama's Kenyan grandmother, known as Mama Sarah, vowed Friday to cook a traditional meal for her grandson when he visits the East African nation, the birthplace of his father, later this month. "With regards to what food I will prepare for Barack on his visit, I will prepare all the traditional food available," she said, speaking her Luo language through a translator on a visit to Nairobi. She tempted him with the offer of dishes including fish, chicken and maize porridge.