I had known it since my school days and the below mentioned controversy is actually a bit late in the day. Its a historically validated fact that the early vedic preachers were non-vegetarians who even offered the NV stuff to the gods and that they used to even eat cows and buffalos. You can actually dig into the early vedic upanishads and vedas and you can dig out the stuff. Harappan material offers evidence that beef was eaten and so will some of the early texts.
However it was only in the later vedic period and the early brahmanical period that things changed and you had a community of vegetarians and a community of non-vegetarians.
Many things changed remarkably in the later vedic period. Indra was regaled to the background, women were restricted etc. etc. The later vedic period saw the trinity coming to the fore and women taking a back burner. The Gargis, Maitreyis, Arundathis etc. were all closeted.
Read on this article. Also the attached pic was shot by me at the team outing:
Aryans were beefeaters: NCERT
Monday May 29 2006 00:30 IST
NEW DELHI: Refusing to delete objectionable content from the school books, the National Council for Educational Research and Training has submitted before the Delhi High Court that the Aryans, including the ‘Brahmins’, were beefeaters in the ancient days.
Appearing before a Division Bench headed by Justice M.K.Sharma, NCERT counsel Prashant Bhushan said, ‘‘The three-member expert committee opined that Aryans were beefeaters and the Council could not distort historical facts by deleting the paragraphs.’’
The Arya Mahasabha and Brahman Samaj opposed the submission by the NCERT and sought the direction of the court for the deletion of the remarks, saying it had bad impact on the students. ‘‘Cows are worshipped by the Aryans and Hindus since the vedic period,’’ said Arya Mahasabha.
Life.. 
