Breathe in, breathe out, and drop the Coke

If David Cameron wishes to take fresh advice on how to increase happiness, now that the American psychologist who inspired his well-being index has admitted that the theory needs some adjustment, he might find it fruitful to study a new book by Sulak Sivaraksa.

The 78-year-old Thai Buddhist, twice nominated for the Nobel Peace Prize and a winner of the Right Livelihood Award (considered the "alternative Nobel"), has been called "one of Asia's leading social thinkers" by Burma's Aung San Suu Kyi. It is possible, however, that if the Prime Minister were to leaf through The Wisdom of Sustainability: Buddhist Economics for the 21st Century, some of Sivaraksa's conclusions might strike Cameron as a little strong.

"Globalisation," he writes, "is a demonic religion imposing materialistic values," and "a new form of colonialism". If Cameron is fond of the odd cola on the beach, he'd better stop. "To drink Coca-Cola or Pepsi-Cola in Siam is not just to ingest junk food, but to support exploitative values." Economic crises such as those that hit the West in 2008 and East Asia a decade earlier are "heavenly messengers" to "encourage us to seek alternative" models – as Sivaraksa told a no doubt startled James Wolfensohn, the former president of the World Bank.

These may be tough words, but Sivaraksa is not one for thinking great thoughts from a monastic seclusion that means he never has to try them out in practice. Over four decades, he has set up numerous NGOs in Thailand, taught at universities across the world and advised the government of Bhutan on how to implement its famed concept of Gross National Happiness. His efforts have been recognised with numerous awards, the latest of which is the Niwano Peace Prize, which comes with a cheque for around £150,000. (The ceremony was due to take place in Tokyo this month but has been delayed because of the tsunami.)

He also had to go into exile twice, when his forthrightness about the coups that occur frequently in his country led to threats on his life. "The first time was accidental," he tells me in his leafy garden, which is a miraculous hidden oasis amid the concrete chaos of Bangkok. "I was in London, and found out from the newspaper that I had been arrested in absentia. They burnt all my books. They would have burnt me alive too, so, like a brave man, I stayed away. The second time, the coup leader was very angry with me. He would have done anything." The School of Oriental and African Studies in London and Cornell University in New York provided a safe haven on each occasion.

Sivaraksa's outspokenness originally stemmed from a desire to bring Western-style freedoms to his country. He was educated in the late 1950s at what is now the University of Wales, Lampeter, where he was one of very few foreigners: "Once, in Carmarthen, two ladies saw me. One said to the other: 'Black man!' I turned to her and said, 'Not quite, madam.'" When he returned to Thailand, he thought he had "the Western answer": "We, the elite can change the world. The plebs will follow us." However, after working with the poor he began to follow their example instead. "I learnt from those who suffer."

Sivaraksa's view is that true happiness is not to be found in material gains or in the constant pursuit of unlimited growth, but starts with the search for inner calm. "You in the West have been indoctrinated by the Cartesian concept of thinking: I think, therefore I am. But the ego, the 'I' – it's not real. We are all inter-related." His path is not "cogito ergo sum" but "I breathe, therefore I am".

"We breathe all the time, yet we are not taught how to. Are we so arrogant that we ignore the most important element in life? Once you learn how to breathe properly, respect the air, cultivate peace within, that is the beginning of Gross National Happiness."

It also means doing away with what he considers the West's "mania for success": "Real success is not to conquer others, not to have more cars and money, but to appreciate what you have, how to share with others."

He admits that what he proposes may strike some as "Eastern garbage". Neither would all find it easy, or even desirable, to follow one example he gives of a friend in America: "He noticed that when a man he knew missed a bus, he would say, 'Wonderful! I have more time to contemplate.' The same when the train was late. My friend asked how he had this attitude, and he said: 'I'm a Buddhist.'"

Instead, Sivaraksa stresses that the West has its own traditions that he thinks we should revisit. "You need to go back into your spiritual past, to those such as Francis of Assisi. In my opinion, that's very close to the Buddhist approach." For Sivaraksa, a rationalism that only accepts what can be proven scientifically has led us to ignore riches from our own culture. "The West took Plato, Socrates and Aristotle only on the intellectual level. Plato's the man! Everything else is footnotes. But in Plato, there is also mysticism – being in the cave, talking to the gods. You dismissed all that."

Sivaraksa suggests that the West should open itself up to "cognitive diversity", to truths from different cultures. "As Gandhi said, 'Any wind coming through.'" Or, as Sivaraksa puts it in his new book: "We uncritically accept 'established knowledge' ... It is time for us to question the fundamentals of the Enlightenment in order to become truly enlightened."

How, though, I ask him, can governments incorporate these ideas into practice? "You don't persuade a whole society to become humble," he responds. "That is a very Western approach. With GNH you have to start with personal happiness, with helping others and the feeling that others are more important than us. You have to ask yourself, how will this tree be happy? When people change, then the governments will change."

If we do not turn to a less I-driven future, Sivaraska says, we will reap the consequences. "Even nature suffers because of our arrogance. We think we can control it. But look at Japan, at Chernobyl, and Bhopal. If we don't bring a spiritual essence into our lives ... bang, we're finished."

He is pleased that in Europe, less materialist notions of well-being are being considered more seriously, with Richard Layard, Geoff Mulgan and Anthony Seldon setting up their Action for Happiness group, and the Nobel laureate economists Amartya Sen and Joseph Stiglitz advising the French on how to look beyond GDP. Still, Sivaraksa cautions that "the West needs to be more qualitative than quantitative". We have a long way to go, he thinks. "Stiglitz is a very nice man," he says, "but I'm afraid even he has not learnt how to breathe properly yet."

The Wisdom of Sustainability: Buddhist Economics for the 21st Century by Sulak Sivaraksa (Souvenir Press £10)

"Capitalism brainwashes us through advertising and the skewing of priorities .... We need economies that promote human values, seek to limit suffering, and are committed to democratic principles, rather than ones dependent on global trade and a blind commitment to neo-liberal economic policies."