There are three kinds of food a human being needs to be alive:
- Ordinary food (i.e. all that is edible such as vegetables, meat, etc.)
- Impressions (i.e. all that you perceive internally and externally)
The title of this post is "Onion and garlic" because these two kinds of "ordinary food" are of a rajasic ("rājasa" in right Sanskrit) nature. Since Rajas (a quality of Nature) is passion, activity and the like, if one eats onions and/or garlic, he will develop passion, anxiety, etc. This is the theory at least, and it might be true indeed. Well, the problem is that the benefits of eating onion and garlic exceeds the possible inconveniences. The onions are extremely disinfecting and garlic lowers your blood pressure. That is why the latter is recommended for people suffering from high-blood pressure.
Anyway, even if you neither need disinfect your body nor lower your blood pressure, and decide not to eat onion and garlic so that passion, anxiety, etc. stay away from you, remember the following:
It is a waste of time to avoid onion, garlic and in fact any other rajasic food, and afterward to go out on a spree or watch porno movies on the TV, etc. Your behavior should be consistent with your diet, or the latter is useless. Why? Because the third food (impressions) is the most important. If you allow "anything" to enter your senses and mind, your system will be troubled whether or not you are meticulous about your diet. So, one should be careful with the impressions in the first place. For that reason, scriptures insist on having good company, that is, the company of people who are helpful in your sādhanā or spiritual practice, specially when you are a beginner in Yoga or any other path. A good company is "good impressions", while a bad company is "bad impressions". A bad company will hurt much more than 100,000 onions and 100,000 garlics, no doubt about it.
The quality of air you breathe and the way you do it comes in the second place. Still, you must learn how to change this with the help of a proficient master. If you do not have good knowledge about it, you will harm the system. So, if you do not have any master for now, let your breath alone, please. The intelligence controlling the physical body will regulate your breathing for you.
Finally, my own experience:
I have noted that people who is too meticulous about avoiding onion and garlic, for example, are extremely negligent about avoiding bad impressions. They are mostly maniac and violent. Why? Because one becomes what he rejects. The more you reject something, the more you become like that. Therefore, one should be careful but not extremist, got it? There is an interesting well-known story of a guy and a donkey, which carried a tremendously heavy burden of logs on its back. To alleviate the donkey, the guy made the decision to remove two little sticks. He said: "Well, this should do the trick". It is stupid, isn’t it? Likewise, if you are too meticulous about what is insignificant in itself and neglect what is very important, you will be behaving like that foolish fellow.
I personally do not pay too much attention to "ordinary food" in my life, at least from an intellectual viewpoint. My body knows what to eat and what not to eat, and informs me about it quickly. Everybody has this capacity but they maybe do not know it. Do this: Bring the food near your mouth and nose, and "feel". If it will be harmful, your body will clearly tell you. It is generally better for you to trust what your body tells you. All theories about what one should or not eat come from the intellect and are useless for the most part. A confession: I eat onion, garlic, meat, eggs, etc. In fact, my best translations have been published after eating a good hot-dog, and I am not joking. Knowledge, Liberation, etc. have nothing to do with avoiding onion, garlic and so on. The importance of ordinary food regarding Knowledge, Liberation and so on is like that of the two little sticks in the story I told you before.
Thus, make sure that your "impressions" are of high quality (good company, good thoughts, good emotions, etc.), and the body will do the rest for you. And if you stumble upon an expert guru who teaches you how to breathe adequately, much better. But, please, forget about diets during your sādhanā. Yes, a lot of people will not agree with me as they have probably devoted their lives to avoid onion and garlic, hehe, or maybe because they are selling a special diet or something, you know, but this is their problem not mine. Well, my hot-dog is waiting for me, see you!