It takes longer to tame than the timer says because the cool down on the veggie cake is 30 sec and for that time it's like there is no food in it's inventory. It loses about 1% of progress each time it eats because of the cool down.
If you are considering breeding these, go slam your hand in a car door a few times. It will be much less painful. Literally one veggie cake per percent of growth....and it grows slow.. Digests roughly one point of food per second, so feed a cake about one for every 7 mins (during event boost) and it will gain one percent of growth.