As-Salāmu `Alaykum (السلام عليكم):
marwen:
A Muslim adhering to a vegan diet is following the laws of Allah. Choosing not to eat meat is a choice. Eating meat is not Fard (Obligatory), an exception is slaughtering and sacrificing meat for Id and distributing it. The availability of Hilal meat is a issue in many non Muslim countries.
Sahih Al Bukhari Volume 7, Book 68, Number 477:
Narrated 'Aisha:
We used to salt some of the meat of sacrifice and present it to the Prophet at Medina. Once he said, "Do not eat (of that meat) for more than three days." That was not a final order, but (that year) he wanted us to feed of it to others, Allah knows better.
Sahih Al Bukhari Volume 7, Book 68, Number 480:
Narrated Salim:
'Abdullah bin 'Umar said, "Allah's Apostle said, "Eat of the meat of sacrifices (of 'Id al Adha) for three days." When 'Abdullah departed from Mina, he used to eat (bread with) oil, lest he should eat of the meat of Hadi (which is regarded as unlawful after the three days of the 'Id).
Note: The evidence above is not advocating that the Prophet Muhammad (SAWS) only ate meat during Id or that eating meat is only lawful during Id and three days after.
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There are foods you don't eat which is a choice.
Surah An'am
6:141 It is He Who produceth gardens, with trellises and without, and dates, and tilth with produce of all kinds, and olives and pomegranates, similar (in kind) and different (in variety): eat of their fruit in their season, but render the dues that are proper on the day that the harvest is gathered. But waste not by excess: for Allah loveth not the wasters. (Y. Ali translation)
Surah Ra'd
13:4 And in the earth are tracts (diverse though) neighbouring, and gardens of vines and fields sown with corn, and palm trees - growing out of single roots or otherwise: watered with the same water, yet some of them We make more excellent than others to eat. Behold, verily in these things there are signs for those who understand! (Y. Ali translation)
Surah Nahl
16:11 With it He produces for you corn, olives, date-palms, grapes and every kind of fruit: verily in this is a sign for those who give thought. (Y. Ali translation)
Surah Waqi'ah
56:29 And clustered plantains (bananas), (Picktall translation)
Surah Baqarah
2:61 And remember ye said: "O Moses! we cannot endure one kind of food (always); so beseech thy Lord for us to produce for us of what the earth groweth, -its pot-herbs, and cucumbers, Its garlic, lentils, and onions." He said: "Will ye exchange the better for the worse? Go ye down to any town, and ye shall find what ye want!" They were covered with humiliation and misery; they drew on themselves the wrath of Allah. This because they went on rejecting the Signs of Allah and slaying His Messengers without just cause. This because they rebelled and went on transgressing. (Y. Ali translation)
The Prophet ate what he liked and he left aside what he didn't like.
This post was submitted with the best intentions. Any positive contribution based on Quran and Sunnah is appreciated.