Apart from adhering to the numerous other injunctions regarding nutrition (such as moderation, eating according to Sunnah etiquette, eating only Halaal, etc.), Islam also enjoins the importance of a good, balanced diet.
Analysis of various verses from the Holy Qur'an clearly show that the foods spoken about in it, will fulfil one's daily protein, carbohydrate, fat and vitamin requirements. Qur'anic verses speak about the importance of, among other things:
Other than Qur'anic verses, we have the authentic Sunnah of Rasulullah (sallallahu-alaihi-wasallam) which also testifies to the importance of a balanced diet. The fact that Nabi (alayhis-salaam) would at times eat cucumber together with dates in order to balance the opposing hot and cold effects in these foods is a proof of this. Many other examples can be cited here as well. For greater information, the detailed works of Hadith such as Shama'il-Tirmidhi can be consulted.
Suffice it to say that extremes in diet were not the practice of our noble Rasul (sallallahu-alaihi-wasallam) and are not recommended in Islam. It is amply clear then that clinging to vegetarianism or only some foods as a diet pattern to the exclusion of other important foods should not be the practice of a Muslim. This is the practice of other nations, not Muslims. Abstaining from some of Allah's favours (for no valid reason) is like turning away from all of His favours! This is a serious thing. In fact, Allah (swt) warns us in the Qur'anic verse: "O ye who believe! Make not unlawful the good things which Allah has made lawful for you...."
At another juncture, He says: "Why should you not eat of meats on which Allah's name has been pronounced, when He has explained to you in detail what is forbidden for you..."
Islam itself is a balanced way of life that is pure from all forms of excesses. A balanced diet fits beautifully into the balanced teachings of Islam. It is a natural corollary to Islam. The Islamic way of life is a natural lifestyle suited to the temperament of mankind at large. Islam is opposed to extremes in the physical as well as spiritual matters of life. Islam always promotes the middle path and this Ummah has been declared in the Holy Qur'an as being 'the nation of the middle path'. So long as Muslims adhere to this general principle of Islam in every matter of their lives, they can look forward to not only good physical health but even an excellent mental, psychological and spiritual state of well being, by the Will of Allah.
Let all believers in the Qur'an endeavour to introduce all of the above mentioned foods into their daily diet patterns. After all, there has to be some very special importance in these foods if Allah (swt) chose to mention them in His Holy Book or they are to be found in the Hadith of Rasulullah (sallallahu-alayhi-wasallam)!
These will, Insha-Allah prove to be the key to a good, healthy life. Let Muslims adopt these and encourage their children to adopt these as a lifelong diet pattern, Insha-Allah!