NEW DELHI (NYTIMES) - Mr Rahul Verma's son was born gravely ill with digestive problems, but over years of visits to the boy's endocrinologist, Mr Verma saw the doctor grow increasingly alarmed about a different problem, one threatening healthy children.

Junk food, the doctor warned, was especially dangerous to Indians, who are far more prone to diabetes than people from other parts of the world.

One day in the doctor's waiting room, Mr Verma noticed a girl who had become fat by compulsively eating potato chips. He decided he had to do something.

"On one side you have children like my son, who are born with problems, and on the other side you have children who are healthy and everything is fine and you are damaging them giving them unhealthy food," he said.

Mr Verma, who had no legal training, sat late into the nights with his wife, Tullika, drafting a petition in their tiny apartment. He filed the public interest lawsuit in Delhi High Court in 2010, seeking a ban on the sale of junk food and soft drinks in and around schools across India.

The case has propelled court-ordered regulations of the food industry to the doorstep of the Indian government, where they have languished. They have outsized importance in India, population 1.3 billion, because its people are far more likely to develop diabetes - which can lead to heart disease, kidney failure, blindness and amputations - as they gain weight than people from other regions, according to health experts.

'SITTING ON A VOLCANO'

Since 1990, the percentage of children and adults in India who are overweight or obese has almost tripled to 18.8 per cent from 6.4 per cent, according to data from the Institute for Health Metrics and Evaluation at the University of Washington.

The International Diabetes Federation projects that the number of Indians with diabetes will soar to 123 million by 2040 as diets rich in carbohydrates and fat spread to less affluent rural areas.

"We are sitting on a volcano," said Dr Anoop Misra, chairman of a diabetes hospital at Fortis Healthcare, one of India's biggest private hospital chains.

In the years since the court ordered the government to develop guidelines to regulate junk food, the case has encountered ferocious opposition from the All India Food Processors Association, which counts Coca-Cola India, PepsiCo India and Nestlé India as members, as well as hundreds of other companies.

President of the association Subodh Jindal said in an interview that junk food was unfairly blamed for diabetes and obesity. It was overeating, not the food itself, that has caused the problem, he said.

The government this year (2017) took a significant step that public health experts believe will help combat the rise of obesity. It partially implemented a tax on sugar sweetened beverages, instituting a 40 per cent tax on such drinks that are carbonated, though not on juices made with added sugars that many children drink.

But so far, the regulations to ban sales near schools sought by the court in Mr Verma's case have led to naught.

Mr Jagat Prakash Nadda, India's Minister of Health and Family Welfare, did not respond to repeated requests for comment, but Mr Pawan Agarwal, chief executive of the Food Safety Standards Authority of India, the body in the ministry responsible for such regulations, insisted that the government's efforts have been sincere.

"This may appear to be typical of India. When you have an issue, you set up so many committees and confuse the whole issue," he said. "People are concerned. They want to do something about it. Therefore everyone is setting up committees."

As the case has played out on Twitter and in newspapers, some schools have voluntarily stopped serving junk food.

Mr Verma, 42, quit his job as a corporate marketing executive after his son's birth in 2006 and set up a foundation in 2007 to help families like his with sick children. At one point, though, Mr Verma begged the judge to let him withdraw the petition.

But Chief Justice Dipak Misra refused. Instead, spotting a senior advocate Neeraj Kishan Kaul in the courtroom, the judge ordered him to act as the pro bono lawyer for Mr Verma's case.

As Mr Kaul, 54, approached the bench, he recalled, he joked to the judge, "You've got the wrong guy. I like junk food."

AN INCREASED RISK

Scientists searched for genes that predisposed Indians to diabetes, but did not find them. Instead, a growing body of research suggests that Indians' body type - one that is smaller but with more abdominal fat - may be responsible.

Being born to a malnourished woman, a common phenomenon in India, may also increase the odds of developing diabetes.

Dr Chittaranjan Yajnik, a diabetes specialist, and professor of nutrition Barry Popkin at the University of North Carolina, are among the researchers exploring a theory that Indians evolved what Dr Yajnik has called "a thin-fat" body type over millenniums as a way to survive famines when monsoons failed.

In the 1990s, Dr Yajnik began following the pregnancies of hundreds of women in villages outside Pune, a city in western India, and tested their offspring as they grew up.

Compared with infants in Britain, Indian newborns were about 1.5 pounds (680 grams) lighter but had more abdominal fat and higher levels of certain hormones in their cord blood, he found, suggesting a predisposition to diabetes.

Dr Yajnik said he believes Indians' susceptibility to diabetes may have emerged as their diets changed with rising affluence - and that their bodies, attuned to scarcity, could not handle an overload of food.

Although obesity and overweight are far less prevalent in India (24 per cent last year) than in Canada (about 60 per cent), for example, adults there are just as likely to develop diabetes as in Canada, a New York Times analysis of data from the Institute for Health Metrics and Evaluation found.

In the years since Mr Verma filed his suit, sales of packaged foods have increased 138 per cent; fast food 83 per cent; and carbonated drinks 58 per cent, according to Euromonitor International, the market research firm.

Coca-Cola's chief executive James Quincey, in an interview with Indian media earlier this year, said that he expected the Indian market to eventually become the company's third largest in sales, up from sixth.

Coca-Cola and PepsiCo have announced plans to invest billions of dollars in the Indian market. They have also said they plan to increase their offerings of drinks with less sugar and more fruit.

Mr Sanjay Khajuria, a Nestlé India spokesman, said the food processors association, which opposed Mr Verma's case, had "taken into account inputs received by the association from its members", and declined further comment. He also noted that the company has joined other companies in India to restrict advertising directed at children younger than 12 to products with a certain level of nutrients.

A Coca-Cola spokesman referred questions on the lawsuit to the food association. PepsiCo India's vice-president of sales Harsh K. Rai also declined to comment on the lawsuit. He said the company has stopped advertising to children 12 and younger.

FUTURE OF THE FIGHT

In early 2015, the food authority in the Health Ministry finally recommended regulations to the court, including some limitations on the sale of junk food around schools. The judge ordered the recommendations carried out within three months. Instead, the food authority appointed yet another committee.

Mr Agarwal, chief executive of the food authority, insisted his agency is finally ready to start adopting new rules early next year for labelling healthy food with a green light and those high in fat, sugar and salt with a red light.

But he said taxing junk food and banning it around schools were long-term goals.

"There is no point in confronting industry on these issues," he said.

Mr Verma was emphatic that someone needs to continue the fight; he is just not sure that someone is him. He is convinced the unending legal battle gave him high blood pressure.

His former partner on the case, pro bono lawyer Mr Kaul, said India needs more than Mr Verma to make change happen.

"You need a movement to fight the inertia of the system," he said, sipping a can of Coke.