The value on the x axis is how much you've fed her, the value on the y axis is how far along she is (the value that is shown as % on the save slot in the main menu), y * 10 = current friendship. She needs like 125000 nutrition to get her to the first friendship level, so you probably haven't fed her enough. To speed up the process, you can level your character up and it will give the goddess a bonus for certain types of food depending on which body parts you have leveled up. I would also recommend that you use higher nutrition foods.
