Soft drink giants Coca-Cola and PepsiCo are locked in a neck-and-neck battle to become new best friends of public health. It’s what you do, apparently, when your industry is facing flak as an enemy of public health.

Coca-Cola recently became the first company to join the American Academy of Family Physicians new corporate membership program, enabling it to help “educate consumers about the role their products can play in a healthy, active lifestyle”.

Under the deal, Coca-Cola is providing a hefty grant to the AAFP to develop consumer education content on drinks and sweeteners for the academy’s consumer health website, FamilyDoctor.org.

Prominent US public health nutritionist Professor Marion Nestle has canned the deal, saying it puts the academy in an “embarrassing conflict of interest” when the first piece of advice that family doctors should give overweight people is to drop soft drinks.

Meanwhile, a senior PepsiCo executive, Dr Derek Yach, was visiting Australian research and health organisations last week and participated in a debate at the University of Sydney with the prominent nutritionist and public health advocate Dr Rosemary Stanton.

The gig was well attended, partly because Yach was a respected advocate for tobacco control in a former life at the WHO. You can read more about his illustrious academic career in the announcement of his 2007 appointment as the director of global health policy for PepsiCo.

Stanton argued for a multifaceted approach to obesity, including a tax on the carbon and water footprint of all food and drinks, while Yach stressed that PepsiCo and other food companies are making changes and responding to global concerns about obesity. “The eloquence and the clarity of the argument had been heard by companies and investors, he said.

But Yach also slipped in a few strategic distractions, suggesting that alcohol’s contribution to obesity was being overlooked and that the problems of hunger should not be forgotten.

He also stressed his close connections with many public health luminaries, and that schools of public health should partner with business schools to develop innovative solutions rather than engage in “unnecessary battles”.

The debaters were a study in contrasts — Yach is clearly used to wielding heavyweight institutional and corporate power, while Stanton has the moral authority of a no-strings-attached public advocate who is unafraid to speak her mind.

It left me wondering who is best placed to effect change for health — those on the inside or outside.

Many in the audience weren’t at all convinced that Yach is having much luck in achieving meaningful change within his company. “Corporate capture” and “this is more PR than anything else” were among the comments heard afterwards (you can read more of the reaction at Croakey).

Yach’s credibility took a dive for many in the audience when he rejected suggestions for a tax on junk foods as a “blunt instrument”. After all, it was precisely this sort of blunt instrument that proved so effective in his former field, of tobacco control.

While trying to win over the public health crowd, Yach may have inadvertently helped make an argument that public health should be wary of friends bearing pseudo-sweet gifts.

He also helped answer my question about the relative merits of insider and outsider power. At the end of the day, real change will come only when governments are prepared to use their power to combat public health problems such as obesity.