Fair enough, but to be straight with you, I would always prefer to read Bahauallah, the fundamental source.
Was Abdul Baha a vegetarian?
OK. From the pen of Baha'u'llah:
"
He should show kindness to animals, how much more unto his fellow man, to him who is endowed with the power of utterance."
Baha'u'llah, "The Kitb-i-Iqan" (Book of Certitude), p. 194.
"Burden not an animal with more than it can bear. We, truly, have prohibited such treatment through a most binding interdiction in the Book. Be ye the embodiments of justice and fairness amidst all creation."
Baha'u'llah, "The Kitb-i-Aqdas" (Most Holy Book), 187, p. 87
I don't know if Abdu'l-Baha was a vegetarian and he wouldn't have been required to be:
"`Abdu'l-Baha has indicated that in the future human beings will be vegetarians, but abstention from eating meat is not a law of this Dispensation."
The Universal House of Justice, Dec 16, 1998
This statement was probably based on the following writing from Abdu'l-Baha:
As humanity progresses, meat will be used less and less, for the teeth of man are not carnivorous … The human teeth, the molars, are formed to grind grain. The front teeth, the incisors, are for fruits, etc. It is therefore quite apparent, according to the implements for eating, man's food is intended to be grain and not meat. When mankind is more fully developed the eating of meat will gradually cease."
'Abdu'l-Bahá, from "Star of the West", Vol.III, No.10, p29.