Before anyone leaves the comment, "Luther's was a diet worms" I've stolen your thunder.
This one has popped up on two discussion boards (here and here), and also is enshrined in this link: Veg World, For all things Vegetarian and Vegan. Also this power point presentation mentions it.
Vegetarians in History
If you were to list every famous vegetarian, you would fill a large city's phone book. Here are a few particularly notable ones.
1483 – 1546
German church reformer; founder of Protestantism
This is probably a confusion between Martin Luther and Martin Luther King. The usual charge of course is that Luther was a glutton, eating and drinking to excess. Now he's a vegetarian! But Luther does say:
You see also what sort of food He provides for us, namely, herbs and fruits of the trees. Hence I believe that our bodies would have been far more durable if the practice of eating all sorts of food—particularly, however, the consumption of meat—had not been introduced after the Deluge. Even though the earth was cursed after Adam’s sin and later on, at the time of the Deluge, had also become very corrupt, nevertheless a diet of herbs rather than of meat would be far finer today. Indeed, it is clear that at the beginning of the world herbs served as food and were created for this use, that they might be food for man.[LW 1:36]
after men were permitted to eat meat, they became weaker, and that they began to beget children as well as to die at an earlier age. Having originally brought on our death by eating the fruit, we hasten our death by the variety of our food and by our gluttony. If we used plain foods, without foreign spices, which stimulate the appetite, we would undoubtedly enjoy a longer life. [LW 11:231]
However, note the following:
Let us proceed and speak of the eating of meats and what our attitude should be in this matter. It is true that we are free to eat any kind of food, meats, fish, eggs, or butter. This no one can deny. God has given us this liberty; this is true. Nevertheless, we must know how to use our liberty, and in this matter treat the weak brother quite differently from the stubborn. Observe, then, how you ought to use this liberty.
First, if you cannot abstain from meat without harm to yourself, or if you are sick, you may eat whatever you like, and if anyone takes offense, let him be offended. Even if the whole world took offense, you are not committing a sin, for God can approve it in view of the liberty he has so graciously bestowed upon you and of the necessities of your health, which would be endangered by your abstinence. Secondly, if you should be pressed to eat fish instead of meat on Friday, and to eat fish and abstain from eggs and butter during Lent, etc., as the pope has done with his fool’s laws, then you must in no wise allow yourself to be drawn away from the liberty in which God has placed you, but do just the contrary to spite him, and say: Because you forbid me to eat meat and presume to turn my liberty into law, I will eat meat in spite of you. And thus you must do in all other things which are matters of liberty. To give you an example: if the pope, or anyone else were to force me to wear a cowl, just as he prescribes it, I would take off the cowl just to spite him. But since it is left to my own free choice, I wear it or take it off, according to my pleasure. [LW 51:186]
Here's a time when I don't mind quoting Luther's Table Talk:
“In the year 1523 I finally laid aside my habit to the glory of God and the confusion of Satan, and many approved of my act for the sake of liberty. If I had not myself taken off my cowl, eaten meat [on fast days], and taken a wife, all the papists would have protested that my teaching isn’t true because I act otherwise than I teach. I couldn’t secure permission anywhere to get rid of the dreadful vestment. It was hard for me to do [but I got rid of it], not because my conscience drove me but for the sake of others to whom I desired to be of service.” [LW 54:338]
Moses seems to be making a difference between the seeds and the green herbage, perhaps because the latter were to serve for the use of the beasts, the former for that of man. I have no doubt that the seeds we use for food today were far more excellent then than they are now. Moreover, Adam would not have eaten the various kinds of meat, as the less delightful food, in preference to the delightful fruits of the earth, whereas for us nothing is more delicious than meat. From the use of these fruits there would not have resulted that leprous obesity, but physical beauty and health and a sound state of the humors. But now people do not content themselves with meats, with vegetables, or with grain; and rather often, because of unsuitable food, we face dangers of health. I am saying nothing about those increasingly widespread sins of overindulgence in food and drink which are worse than brutish. The curse which followed because of sin is apparent. It is also likely that only then were the accursed and pernicious insects produced out of the earth, which was cursed because of man’s sin. But here comes the question of how the granting to Adam of the enjoyment of all the trees of the field harmonizes with the later assignment to him of a single portion of the earth for tilling, the portion called Paradise. It is also asked whether the whole earth is called Paradise, etc. But we shall put off these matters to the second chapter. [LW 1:72]
And you, pope, presume to make it a sin if I do not wear a cowl. But the more persistent the pope is with this demand, the more resolutely must I defy him. They make bold to declare it a sin if I marry a nonvirgin, and they declare me qualified for the ministry if I marry a pure virgin. I suppose I could abstain from meat if free choice were accorded me in the matter. But if the eating of meat is to be stamped as sin, I shall not abstain. If they tell me: “You owe the church obedience, and this is forbidden by the church!” I reply: “I refuse to fast, just because you demand it; for so I have been commanded, or I forfeit eternal bliss.” In such an event I must insist on my Christian liberty.[LW 22:451]