13/08/2015 09:55 BST | Updated 13/08/2016 06:59 BST

Why Is Coca Cola Trying to Bambooze the Public Over the Causes of the Obesity Crisis?

The soft drinks giant has seen a growing movement around the world against consumption of sugary beverages and is now recruiting prominent scientists as part of its fight back. Their message is that obesity is not caused by the foods or drinks we are consuming, it is caused by our failure to balance those foods with exercise. This is a transparent attempt to confuse people about the real drivers of the obesity epidemic.

According to a report in the New York Times, Coca Cola has provided funding and logistical support for a new organisation, the Global Energy Balance Network, whose launch was announced in the British Journal of Sports Medicine last March. The Network claims to have the support of almost 150 experts in 18 countries on six continents and its website describes its mission as: "Healthier living through energy balance."

In the launch editorial three US experts argued that the public and many scientists have largely overlooked physical inactivity as a cause of obesity and said the Network was being created to raise awareness "about both sides of the energy balance".

The New York Times reported that Coca Cola invested $1.5 million last year in the new organisation, and has also provided almost $4 million in funding for various projects to two of the organisation's founding members since 2008. The network's website, which is registered to Coca Cola headquarters in Atlanta, says there is "strong evidence" that the key to preventing weight gain is not eating less but "maintaining an active lifestyle and eating more calories." This claim is backed with links to two research papers, both supported by Coca Cola.

These assertions are at best misleading, at worst irresponsible. The rise in obesity, and the diabetes it causes, is one of the greatest health challenges the world faces. In May, the World Health Organization warned that by 2030, three quarters of men and two thirds of women will be overweight in the UK.

Of course we know that obesity occurs when the calories consumed in the shape of food and drink exceed the calories expended in energy. But we also know that exercise, though vital for health, has a minimal impact on weight. A 350 ml can of Coca Cola contains almost 10 teaspoons of sugar, equivalent to 139 calories, and takes 40 minutes of brisk walking to burn off for a person weighing ten stone.

Consuming extra calories is much easier than expending them. That is why the vast majority of scientists recognise that the focus should be on curbing calorie intake.

This is especially true of sugary drinks which are now recognised as major contributors to the global obesity epidemic. There have been moves worldwide to tax soft drinks, remove them from schools and stop companies from advertising them to children. In the US, consumption of full-calorie fizzy drinks has fallen by a quarter in the last 20 years.

Coca Cola is desperate to stop the slide. Its attempt to harness scientists in its support recalls the efforts of the tobacco industry. It too funded scientists to become "merchants of doubt" about the dangers of smoking. Similar efforts have been made by fossil fuel industries in the battle over climate change.

Funding by industry is not unusual in scientific research. As a researcher myself, I know how difficult it can be to attract grants. But the dangers of accepting money from the industry whose products you are studying is well known.

A review of soft drinks research published in the journal PLOS Medicine found those funded by Coca Cola, PepsiCo, the American Beverage Association and the sugar industry were five times more likely to find no link between sugary drinks and weight gain as those whose authors reported no financial conflicts.

Sugar is one commodity of which the world is not short. Indeed, its excess is killing us in our millions. Science, and scientists, are diminished when they are recruited to muddy the evidence in defence of the indefensible.

Lord Darzi is a surgeon and director of the Institute of Global Health Innovation at Imperial College London. He was a Labour health minister from 2007-9.