Jean Dreze began his adult life as a Belgian mathematical economist with a fine academic record who could have, if he'd chosen to, joined a rich pharma multinational or an international bank or even the Belgian bureaucracy.

Instead today, at the ripe old age of 44, Dreze has chosen to become an Indian citizen who specialises in action-oriented development economics and has collaborated with Nobel Prize winner Amartya Sen to understand the structure of poverty and famine in India.

He is an honorary professor at the Delhi School of Economics (D-school) and lives with wife Bela (also a non-conformist) sometimes in Delhi but mostly in such glamorous places as Kalahandi and Moradabad.

He travels by bus or train, but also enjoys racing scooters or his preferred mode of transport, a bicycle, as I found out when I met him for lunch at Sharma Restaurant in Delhi's Kamla Nagar.

It took me a year to set up lunch because Dreze is rarely in town. For what it charges — Rs 400 per student per month — D-school is parsimonious with secretarial assistance.

So, messages left for him never reached Dreze. Nothing much has changed in this place, I thought to myself, as I climbed to Dreze's eyrie on the second floor and, panting slightly, picked my way through broken-down desks, chairs and bookshelves, through shafts of dusty sunlight, to his swelteringly hot (and naturally, not air-conditioned) room.

Dreze's room is plain, dusty but meticulously organised. Everything is in its appointed place, from books to paper clips, stacked neatly on a tray.

Dreze himself is thin as a rake and very much the poster boy of some of the girls in D-school. He is a gentle, shy beanpole, an oddity to some but a hero to many students.

Dreze's formal qualifications are impressive which is why his interest in development economics has credibility. He is no airy-fairy NGO-type lapsed economist.

"I finished with the hard part — mathematical economics — first, and was free to address my interest, action-oriented research later," he said with a smile.

After he finished "the hard part" at the University of Essex, faintly dissatisfied with his life as an academic, he decided to come to India to live the development reality first hand.

He joined the Indian Statistical Institute (ISI) for a PhD in Cost Benefit Analysis in 1979, the year India had its worst drought and therefore, the world's biggest Food-for-Work programme. "I wanted to study how India intervened in drought," he said.

In the summer of 1980, he set off on a cycling tour of Jaipur, Ajmer, Kota and Bhopal and saw relief works for himself.

"Amartya Sen's book on poverty and famine had just come out. The book explained why famines happened. But it seemed to me that famine prevention through public intervention also deserved some attention," he said.

"So I wrote to Amartya Sen about famine prevention that I'd seen in India. That's how we began our collaboration" he said.

Dreze finished his PhD in 1983 under the joint supervision of the ISI and Nicholas Stern, a world authority on public finance who was teaching at the University of Warwick.

Meanwhile, India had got its hooks firmly into Dreze. While in Delhi, rather than stay in a hostel, he lived in a slum in Safdarjung. ISI lore has it that he used to deliberately starve himself to understand what it was like to be hungry. "Is this true?" I asked him curiously. He looked sheepish.

"Well, I used to fast," he conceded. "But it didn't really achieve much. So I gave it up — it became boring after a while," he said, shifting in his chair.

I was getting hungry myself, so we decided to repair to Sharma Restaurant, Dreze on his bicycle, kurta flapping in the breeze.

Part of the intoxicating landscape of Delhi University is a dharamshala opposite Sharma Restaurant that has commandeered part of the pavement for its tandoor and dining hall.

So we had "Sharma" food — wholesome "deluxe" vegetarian thalis at Rs 65 each with two veggies, raita, dal and kheer — to the musical accompaniment of the sounds of repeated traffic jams — blaring horns, cursing in Hindi and English and the sound of scraping fenders.

Around us, hostellers were eating with the silent concentration of people who don't know when they will have their next meal.

For a year after his PhD, Dreze lived in a village in Moradabad and published a study on economic development in an Indian village.

"Several studies on Palanpur had been done before. Ours was done as India was going through economic reforms. The lessons we learnt were that reforms had led to growth in income but state inaction and social inequalities were responsible for the breakdown in public facilities. Because of caste, class and gender divisions, collective action did not take place. So there was no reflection of the growth of income on public facilities and institutions," he said.

The high point of the story of his life in the next five years was extensive field work on poverty, hunger and public action. He shuttled between India and England for his book with Sen. I asked him what it was like working with Amartya Sen.

"Writing a book with someone else is hard work, because you have to agree on every single sentence, but in the end it is very rewarding. I learnt a lot," he said.

In between, Dreze decided he just had to work with the peace movement and helped the Gulf Peace Team set up a camp on the border of Iraq and Saudi Arabia, which he and other idealists hoped would prevent Gulf War I from happening.

"Of course we didn't succeed and the camp was evacuated by the Iraqi government and sent to Jordan," he said, "but we studied the effect of sanctions on child mortality and found it had doubled because of sanctions."

Since 1992, he has been in India almost full-time. In 1994, Bela Bhatia and he formalised a long relationship and got married. Two years ago he became an Indian citizen.

"I was amazed that I got citizenship so easily. It was a long wait, but I'd been involved in all kinds of activity and they could have raised questions. But they didn't. To me, this represents the Indian outlook to dissent and toleration. Now there are all kinds of authoritarian tendencies springing up. But the popular attitude to dissent remains basically democratic," he said.

Today, Dreze is at the end of 10 years of research and action and does not regret one moment.

"We are taught that you have to be objective in doing academic research and if you take part in events, you are not objective enough to look at the world from a distance. So to be objective you should not be involved. But while you must recognise facts for what they are, you don't have to jettison your values," he said, summing up a debate that has racked students of research methodology for centuries.

Accordingly, Dreze is associated with a public interest litigation in the Supreme Court on the right to food, helps the Akal Sangharsh Samiti in Rajasthan to formulate tools of economic analysis and research, and has time for any advocacy group that needs his help in evolving survey methods.

"So what do you do when you want to be really degenerate?" I asked. "If you're out in Barmer and you have a craving for... a Hagen-Dazs ice-cream," I floundered. He laughed.

"I don't have those kind of cravings. There are times when I crave privacy. I don't mind crowded trains. But sometimes you just want to be alone," he said. "And holidays?" I asked. "Oh, I go walking," he said with a grin, "in Kalahandi, in Madhya Pradesh... Gandhiji said change of work is holiday."