Why do we chant Om?

Om is one of the most chanted sound symbols in India. It has a profound effect on the body and mind of the one who chants and also on the surroundings. Most mantras and vedic prayers start with Om.
All auspicious actions begin with Om. It is even used as a greeting - Om, Hari Om etc. It is repeated as a mantra or meditated upon. Its form is worshipped, contemplated upon or used as an auspicious sign.
Om is the universal name of the Lord. It is made up of the letters A (phonetically as in "around"), U (phonetically as in "put") and M (phonetically as in "mum"). The sound emerging from the vocal chords starts from the base of the throat as "A". With the coming together of the lips, "U" is formed and when the lips are closed, all sounds end in "M".
The three letters symbolize the three states (waking, dream and deep sleep), the three deities (Brahma, Vishnu and Shiva), the three Vedas (Rig, Yajur and Sama) the three worlds (Bhuh, Bhuvah, Suvah) etc. The Lord is all these and beyond.
The formless, attributeless Lord (Brahman) is represented by the silence between two Om Chants. Om is also called pranava that means, "that (symbol or sound) by which the Lord is praised". The entire essence of the Vedas is enshrined in the word Om. It is said that the Lord started creating the world after chanting Om and atha. Hence its sound is considered to create an auspicious beginning for any task that we undertake. The Om chant should have the resounding sound of a bell (aaooommm).
Om is written in different ways in different places. The most common form symbolizes Lord Ganesha’s. The upper curve is the head; the lower large one, the stomach; the side one, the trunk; and the semi-circular mark with the dot, the sweetmeat ball (modaka) in Lord Ganesha's hand. Thus Om symbolizes everything - the means and the goal of life, the world and the Truth behind it, the material and the Sacred, all form and the Formless.Om is one of the most chanted sound symbols in India. It has a profound effect on the body and mind of the one who chants and also on the surroundings. Most mantras and vedic prayers start with Om.
All auspicious actions begin with Om. It is even used as a greeting - Om, Hari Om etc. It is repeated as a mantra or meditated upon. Its form is worshipped, contemplated upon or used as an auspicious sign.
Om is the universal name of the Lord. It is made up of the letters A (phonetically as in "around"), U (phonetically as in "put") and M (phonetically as in "mum"). The sound emerging from the vocal chords starts from the base of the throat as "A". With the coming together of the lips, "U" is formed and when the lips are closed, all sounds end in "M".
The three letters symbolize the three states (waking, dream and deep sleep), the three deities (Brahma, Vishnu and Shiva), the three Vedas (Rig, Yajur and Sama) the three worlds (Bhuh, Bhuvah, Suvah) etc. The Lord is all these and beyond.
The formless, attributeless Lord (Brahman) is represented by the silence between two Om Chants. Om is also called pranava that means, "that (symbol or sound) by which the Lord is praised". The entire essence of the Vedas is enshrined in the word Om. It is said that the Lord started creating the world after chanting Om and atha. Hence its sound is considered to create an auspicious beginning for any task that we undertake. The Om chant should have the resounding sound of a bell (aaooommm).
Om is written in different ways in different places. The most common form symbolizes Lord Ganesha’s. The upper curve is the head; the lower large one, the stomach; the side one, the trunk; and the semi-circular mark with the dot, the sweetmeat ball (modaka) in Lord Ganesha's hand. Thus Om symbolizes everything - the means and the goal of life, the world and the Truth behind it, the material and the Sacred, all form and the Formless.

Why do we fast?

Most devout Indians fast regularly or on special occasions like festivals. On such days they do not eat at all, eat once or make do with fruits or a special diet of simple food.
Fasting in Sanskrit is called upavaasa. Upa means "near" + vaasa means "to stay". Upavaasa therefore means staying near (the Lord), meaning the attainment of close mental proximity with the Lord. Then what has upavaasa to do with food?
A lot of our time and energy is spent in procuring food items, preparing, cooking, eating and digesting food. Certain food types make our minds dull and agitated. Hence on certain days man decides to save time and conserve his energy by eating either simple, light food or totally abstaining from eating so that his mind becomes alert and pure. The mind, otherwise pre-occupied by the thought of food, now entertains noble thoughts and stays with the Lord. Since it is a self-imposed form of discipline it is usually adhered to with joy
Also every system needs a break and an overhaul to work at its best. Rest and a change of diet during fasting is very good for the digestive system and the entire body.
The more you indulge the senses, the more they make their demands. Fasting helps us to cultivate control over our senses, sublimate our desires and guide our minds to be poised and at peace.
Fasting should not make us weak, irritable or create an urge to indulge later. This happens when there is no noble goal behind fasting.
The Bhagavad-Gita urges us to eat appropriately - neither too less nor too much - yukta-aahaara and to eat simple, pure and healthy food (a saatvik diet) even when not fasting.