Like many nations around the globe, China is facing a rising trend in obesity thanks largely to changes in diet and lifestyle. According to a recent investigation, at least one global food giant seems to be doing more than just supplying surplus calories.

Researchers from Harvard University have teased apart a complex web of institutional, financial, and personal connections to reveal the potential influence Coca-Cola has over China's health policies. While it stops short of claiming conspiracy, all signs point to an all too familiar set of corporate tactics.

The academic-sounding International Life Sciences Institute (ILSI) has been operating as a non-profit science body in the US since it was founded by Coca-Cola executive Alex Malaspina in 1978.

With current membership comprising of various food and beverage organisations, such as Nestlé, McDonalds, and PepsiCo, and historical connections with the tobacco industry, their goal to "provide sciences that improves human health and well-being and safeguards the environment" has long been a controversial one.

Five years ago, anthropologist Susan Greenhalgh conducted dozens of interviews with Beijing-based obesity experts in an effort to understand what was behind a recent jump in body mass of the average Chinese citizen.

The results of her evaluation might not expose the full story, but they're strongly suggestive of ILSI's influence over Chinese health ministry's policies via its branch inside China's own Centre for Disease Control and Prevention.

It's a prime position for anybody with vested interest in the commercial success of a food and beverage business. ILSI provides the government with expert advice through regular conferences and workshops, much of which informs government programs and actions.

While the researchers aren't claiming Coca-Cola is directly responsible for China's response to its rising obesity trend, it sure aligns nicely with Coca-Cola's interests. And Greenhalgh has plenty of circumstantial evidence to back up her suspicions.

Coca-Cola's relationship with Chinese authorities stretches back some 40 years, coinciding with the founding of ILSI in the US. It happened to be the first international company to be permitted to operate in the country following decades of isolation under Mao Tse-tung.

Interviews with the founding president of the Chinese Academy of Preventive Medicine Chen Chunming revealed how Malaspina "was very helpful" in connecting underfunded authorities with health research from the west.

"In putting its massive resources behind only one side of the science, and with no other parties sufficiently resourced to champion more balanced solutions that included regulation of the food industry, the company made China safe for Coke," says Greenhalgh.

It's a safe ground the company desperately needs. US sales have looked increasingly anaemic in recent years, populations in the eastern hemisphere continue to provide rich opportunity for growth. Throw in a generous amount of adoration for Western culture, and it's clear to see why Coke is It in modern China.

The country has become Coca-Cola's third biggest market by volume, making it increasingly likely to play a crucial part in the future health of the company's business.

One major obstacle standing in its way is the notorious relationship between the consumption of high calorie beverages and weight gain.

To avoid the social costs of rising obesity, governments around the globe have funded healthcare campaigns targeting diets, or sought to impose taxes on high-sugar drinks – actions that hit corporations like Coca-Cola in the hip pocket.

Government policies that focus instead on lifestyle factors such as exercise help maintain a clear path for food companies to maximise profits without them appearing to endorse unhealthy lifestyles.

In 2001, just as the US surgeon general was calling attention to the role high sugar drinks play in obesity, Coca-Cola doubled down on branding associated with exercise and an energetic lifestyle.

The sub-text was clear – sugary drinks aren't a problem if you're active.

While the US has maintained more of a balance in promoting both healthy eating and physical activity in the face of Coca-Cola's lobbying and campaigning, Greenhalgh argues ILSI has played a pivotal role in China's reduced focus on the role nutrition plays in weight gain.

Not only have obesity conferences and workshops been heavily weighted with ILSI presentations, an increasing number of which have focussed more on physical activity, but public health programs have echoed trends towards exercise and movement over recent years.

There are plenty of missing pieces to the puzzle we need to keep in mind. As might be expected, Coca-Cola, ILSI-China, and the Chinese health ministry haven't contributed any official responses.

Criticisms of corporate-sourced expertise are also rather thin on the ground. Many Chinese academics and researchers have a benevolent view of commercial contributions. And why wouldn't they, when competition over public funding is so fierce?

An absence of public watchdogs and unfettered media also makes it difficult to interpret non-critical attitudes towards ILSI.

With plenty of caveats in mind, Greenhalgh makes a strong case for vigilance. While exercise is a necessary part of any solution, the relative absence of nutritional guidance is sure to hinder China's efforts to fight obesity.

Almost half of Chinese adults are considered overweight or obese, a figure that was closer to one in five back in 1991. It's a trend that will prove challenging to reverse without well informed policies that take multiple influences into account.

"With no one to complain about – or even see – this corporate biasing of science and policy, the size and consequences of the Chinese obesity epidemic are likely to continue to worsen," Greenhalgh and her colleagues conclude in their report.

The investigation was published in the BMJ.