In order to achieve all the perks, you will need to feed 164 times in total. I found that the civil war questline gave me a lot of enemies to feed on. NOTE: Only humanoids can be fed on until the Savage Feeding Perk is unlocked
A break down of the number of feedings per perk
Perk 1: 5 feedings
Perk 2: 6 more feedings
Perk 3: 9 more feedings
Perk 4: 11 more feedings
Perk 5: 13 more feedings
Perk 6: 15 more feedings
Perk 7: 17 more feedings
Perk 8: 19 more feedings
Perk 9: 21 more feedings
Perk 10: 23 more feedings
Perk 11: 25 more feedings