If we make a realistic examination of vegetarianism, forgetting for the time being that south Indian brahmins as a community are traditionally inclined towards vegetarianism:
1.) All brahmins are not vegetarians (in our definition of the word), and if I remember correctly, somebody had already pointed this out on this forum. I can at best put only 60% of brahmins in India as vegetarians by tradition, not to speak of those brahmins who do not adhere to their tradition vis a vis their eating habits.
2.) Vegetarian diet, provided it contains all food supplements in adequate quantities, is as rich as non-vegetarian diet. But please do not mistake the miserly diet which some of us take (my sub-sect is legendary for surviving on "chaaru", i.e., rasam, and "chinthakaya pacchadi", i.e., tamarind pickle, though I have deviated from this pattern), as being equivalent to a fullsome non-vegetarian diet. If you observe the food habits of strict vegetarians in north-India, you would find the use of ample proportions of diary products, i.e., panneer, butter, milk & desi-ghee, and also preparations made from a variety of pulses (Rajma, Mattar, Urd, Mung), and plant-protein products such as Soya-beans, Tofu, Makhana, apart from the protein they get from wheat. I generally do not find this emphasis on protein-diet in southern India, though we do consume "paruppu" or "pappu" as one of the food items. According to me, south Indian brahmins should not hesitate to consume some of these "north-Indian" items in thier diet. Give them to your children, particularly if they are below 18, and are in the growing age. Protein supplements can even be taken separately in the form of protein-biscuits (Threptin etc.), Spirulina, Carrigeenin etc. If you are using cow-ghee, do not cut down on ghee intake as a "modern health precaution". After all, the animal fat you are consuming this way is nothing compared to what a regular non-vegetarian consumes. However, avoid all the trans-fats / unsaturated fats (Dalda, Vanaspathi etc.) which are nothing but junk. Also, consume pumpkin curry when it is available, pumpkin being the only source of Omega fatty acids required for brain-functioning in case of vegetarians (the other source being fish).
Any doctor would tell you, and it is proven beyond any doubt, that in the end high protein-diet determines many things apart from muscle mass, such as:
(a) Mental growth & mental health, including IQ. A sound body is generally useful to cultivate a sound mind. Physique is an important part of one's personality. Your mind is influenced by your hormones, which are the products of your body (a famous scientist once said, "give me the hormonal constitution of a person, and I will tell what he is").
(b) Physical stature, general health, immunity, ageing, and average life-expectancy. Without proper protein intake, it is proven that over generations, the average height, weight, and life-expectancy of individuals in a community diminishes ( eg:- studies made over malnurished populations of Bangladesh.)
(c) Stamina to do physical work, and calisthenic skills (sports & games etc.). According to me, every brahmin must cultivate enough physical strength to be in some kind of sport. Brahmin parents should make it a point, that their children pick-up atleast one art (let it be Indian or Western music, Bhrarathanatyam or hip-hop, ceramics or carving & sculpting ; it need not necessarily be a "classical" art form), and one sport (it can be anything, from a martial-sport such as Judo, to cricket or tennis) which they can continue later as a matter of choice, which can be a very fulfilling experience to them, and surely would improve their self-esteem.
(d) Onset of puberty in girls & their reproductive health. There was once a comparative study done by the University of Patiala, Deptt. of Physical Anthropology on the average age for the onset of puberty & reproductive health between girls of Delhi (who get higher protein intake), and girls of few selected villages of Punjab (who are discriminated against in diet matters by their families), vis a vis their average protein intake. We all know about the mishaps the protein-deficient and malnutrient housewives and mothers suffer. They suffer physical and mental damage, fall sick, and die young. We would not want this amongst brahmin women, because the health of their progeny depends upon their health. Our girl children should be healthy and strong. They should also be vocal and assertive! They are surely capable of verbally and physically defending themselves against the kind of comments some of the forum members were mentioning about. Incidentally, I have a daughter who is taller and stronger than many girls of her age (and as a matter of fact, stronger than some boys of her age). She is a strict vegetarian by choice, and not because of my goading, and I am happy about it. She goes to hip-hop classes, and her mother (my wife) has of late taken to Salsa (which she finds very entertaining). After some thinking (and pulling my hair as to whether this would have any "corrupting" influence on their brahmin identity), I have decided not to restrain them in their pursuits.
3.) As for famous personalities who are lacto-vegetarians or vegans, persona such as Carl Lewis, Martina Navratilova, Edwin Moses etc., had converted to vegetarianism in their adulthood on ethical considerations, i.e., they had their share of non-vegetarian diet including beef in their growing ages. Needless to say, they did take lot of care about finding out proper vegetarian substitutes to keep in shape once they became vegetarians. So perhaps comparing ourselves, without proper dietary habits, with those famous vegetarian sports-personnel, would not be proper. This said, there are several strict vegetarian sports personnel whom I am aware of, who have an intimidating physical presence, and can give their non-vegetarian counterparts a run for their money. There exist brahmin communities who do hard physical labour (for example Sankethis) despite their vegetarian diet. But in general, maintaining good physical shape with a vegetarian diet requires more attention and care than to do the same with a non-vegetarian diet. In general, I feel very happy when I see a tall and strong brahmin boy or girl, speaking knowledgibly and assertively, and making a point. There are many of those among my freinds' families, who have done well in sports and studies.
4.) From my personal experimentation, I found that it is generally easy to fall prey to food-contamination (and the resultant sickness) by consuming a non-vegetarian diet than a vegetarian diet. I also found that non-vegetarian diet generally requires heavy masalas to mask the smell of the flesh, and one's body-odours change and become stronger (I am not psychologically prejudiced against non-veg, but speaking from a real experience) when one consumes non-vegetarian diet on regular basis. I do not know the reasons for this, but it is known that meat contains many more toxins than vegetarian diet. It can also be due to all those hormones pumped into animals before slaughtering them. To me, there is also no doubt that temperament changes when one shifts from a vegetarian diet to a non-vegetarian diet, and vice-versa. This may or may not have anything to do with one's physical strength.
5.) To me, maintaining calm under grave provocation is a great skill (and in certain professions people are especially trained for this), and not a weakness. Once upon a time I used to be a very hot-headed young man, and get in to fights easily (to the extent of beating or getting beaten often). That never used to take me anywhere! On the other hand, later in life, there were extreme situations from which I could successfully come out unscathed, just by maintaining a cool-head, and understanding human-psychology a bit. That said, I can understand, and am deeply moved, when one of this forum members, Vijay, says that he has sufferred depression due to the derision he faced in the college. All I can say is that if you "appear" to be "affected" by the ridicule, it is likely to increase. On the other hand, if you train yourself to maintain calm, the people who do this would eventually get frustrated and humiliated.