Gandhi's philosophy and his ideologies of satya (truth) and ahimsa (non-violence) were influenced by the Bhagavad Gita and Hindu beliefs, the Jain religion and the pacifist Christian teachings of Leo Tolstoy. The concept of ‘ahimsa’ (non-violence) has a long history in Indian religious thought and has had many revivals in Hindu, Buddhist and Jain contexts. Gandhi explains his philosophy and way of life in his autobiography ‘The Story of my Experiments with Truth’.

In applying these principles, Gandhi did not balk from taking them to their most logical extremes. In 1940, when invasion of the British Isles by the armed forces of Nazi Germany looked imminent, Gandhi offered the following advice to the British people:

“I would like you to lay down the arms you have as being useless for saving you or humanity. You will invite Herr Hitler and Signor Mussolini to take what they want of the countries you call your possessions.... If these gentlemen choose to occupy your homes, you will vacate them. If they do not give you free passage out, you will allow yourselves, man, woman, and child, to be slaughtered, but you will refuse to owe allegiance to them.” (Non-Violence in Peace and War)

Although he experimented with eating meat upon first leaving India, he later became a strict vegetarian. He wrote books on the subject while in London, having met vegetarian campaigner Henry Salt at gatherings of the Vegetarian Society. The idea of vegetarianism is deeply ingrained in Hindu and Jain traditions in India, and, in his native land of Gujarat, most Hindus were vegetarian. He experimented with various diets and concluded that a vegetarian diet should be enough to satisfy the minimum requirements of the body. He abstained from eating for long periods, using fasting as a political weapon.

Gandhi gave up sexual intercourse at the age of 36, becoming totally celibate while still married. This decision was deeply influenced by the Hindu idea of brahmacharya—spiritual and practical purity—largely associated with celibacy. He announced this to his wife, rather than discussing it with her.

Gandhi spent one day of each week in silence. He believed that abstaining from speaking brought him inner peace. This influence was drawn from the Hindu principles of mouna (silence) and shanti (peace). On such days he communicated with others by writing on paper. For three and a half years, from the age of 37, Gandhi refused to read newspapers, claiming that the tumultuous state of world affairs caused him more confusion than his own inner unrest.

Returning to India from South Africa, where he had enjoyed a successful legal practice, he gave up wearing Western-style clothing, which he associated with wealth and success. He dressed to be accepted by the poorest person in India. He advocated the use of homespun cloth (khadi). Gandhi and his followers adopted the practice of weaving their own clothes from thread they themselves spun, and encouraged others to do so. This was a threat to the British establishment. While Indian workers were often idle due to unemployment, they had always bought their clothing from English industrial manufacturers. If Indians made their own clothes, it would deal a harsh blow to British industry. The spinning wheel was later incorporated into the flag of the Indian National Congress.