Vegetarianism (Vegetarian diet as the food habit) is not at all a hindrance to gain health and intelligence. Nowadays it is scientifically proven too.
"Without eating meat, fish, seafood, how can you be healthy? How can you get all the necessary balanced diet?" are the general questions asked by most of the Westerners especially to the Indian vegetarians, when they come to know that there exist the people who don't eat meat, fish, eggs, etc., but only eat food based on green leaves, vegetables and fruits, pulses and grains, some being lacto-vegetarians and some others being pure vegans.
Not specifically referring to India's problems today, most of which have arisen in the recent decades due to the lost real Indian Vedic culture, India, being culturally and spiritually sophisticated since its ancient past, has such a tradition that today, though there is a majority of population who occasionally eat meat, seafood, fish etc, the same people, abstain from eating meat during some auspicious days of the year.
This is the indirect evidence that all those meat eating Hindus consider it as a sin somewhere deep in their minds though they eat meat often, but refrain from doing it at least on auspicious days like Durga Navarathri, Diwali, Krishnashtami, etc. And many more people observe the abstinence from eating meat during some days of the week as a matter of habit or due to their vows to a particular deity. However in some other religions and tribal cults, people eat more meat especially during their festivals.
Taking into account the ratio of 'meat content to vegetarian food' of different countries (both developed & developing countries), India has the figure which shows that the per capita meat consumption is very less compared to the developed countries of the West. One may raise the issue of India's poverty and try to correlate the same for the low per capita meat consumption. This may be partly correct but is not the complete answer. Indian culture plays an important role for many Indians' choice to remain vegetarian for most part of their time.
Without sound health, you don't have a sound body and sound mind. Without a sound mind, you can’t be happy and can’t lead or perform things in life.
“Do you think today that most of the Indians today are unhealthy and non-performing, because they don't eat so much meat in comparison to the other developed countries, and so are not intelligent?”
Many of us know the answer to this question. A large number of Indians are employed in almost all the developed countries in their world famous companies, these countries need the Indians to work for their companies. Why? Because they are hard working and intelligent. That means they are physically fit and so mentally fit. And many of them are Brahmins (referred here only to drive the point that there are people who never eat meat). If they are physically fit, that means they are healthy and are eating the right food.
So eating meat makes no difference to the performance of the people.
Another fact is that there are some sects of Brahmins who remained lacto-vegetarians for centuries together and even today we find a lot of them practising the lacto-vegetarianism. In the current Indian scenario average Brahmins are not so rich, but are generally intelligent and will raise to higher positions in the society or in their respective fields because of the intellect, spiritual knowledge and the emotional control they possess over the way they lead their lives. This is partly attributed to vegetarianism, and mostly to Vedic tradition, again according to which vegetarianism is a part of a Brahmin's daily practices.
This proves the fact that 'meat eating' is not at all related to the gaining of health or of the intelligence. In fact improvement of health and intelligence is directly related to vegetarianism and is inversely related to meat consumption.
The Indian Vedic Mathematics was developed during the Vedic times and the ancient Indians invented Zero and the decimal numerals system when America hasn’t existed and when the Europeans were nomadic dwellers who were eating raw flesh as uncivilized people.
The eminent scientist Albert Einstein had, in one of his statements, complimented the Indians about their contributions to Mathematics. Max Muller had developed a great interest in Indian literature, and he was a patron of Sanskrit literature and his studies included the Vedas along with the other Indian Epics. The Great personalities like Swamy Vivekananda had mesmerized the western scholars by his intelligence, wisdom and public speaking capabilities which made Swamy Vivekananda, a modern face of Hinduism.
Poverty, Corruption, large population, environment pollution are some of the causes or challenges that are faced by India today due to which there are some dreadful diseases still affecting the people and are causing devastating effects on people's health and hygiene. This is not at all attributable to vegetarianism as a food habit.
Another problem is that some Indians who are getting rich today tend to lose Indian culture by simply copying the western culture, consuming meat and alcohol to show off their elevated status, assuming that as the 'real development'.
Real Development is not the materialistic development alone but it includes the intellectual, spiritual development as well. However all of these above said problems can be controlled and these should not become the deciding factors while discussing the benefits of 'Vegetarianism' and the ill-effects of meat consumption.