And proof means science means R&D.
Last month, Bain, a management consultant, reported that the food industry was becoming an innovation backwater. Food blockbusters were history, the report said. R&D spend as a proportion of sales was less than two-thirds of that of the beauty and personal care industry.
Yet innovation for our industry is more urgent than for almost any other. Other sectors may be picking up the odd media search-light. We are flood-lit.
The evidence and coverage of obesity has turned the media's eyes firmly and long-term to the burning issue of nutrition. In the UK, it has furnished the most talked-about show in town, as chef Jamie Oliver walked millions of viewers through the real content of their children's school dinners. In the US, the first legal actions against food providers seem unlikely to be the last.
And this is no game for sitting out. The cost in lost sales is deterrent enough. At a sectoral level, areas such as crisps and snacks now face forecasts of sales falls of 10 per cent over the next five years. At a corporate level, the financial performance of donut-maker Krispy Kreme speaks clearly to the dangers of products associated with obesity.
But the damage will run deeper than that if not reversed.
In the 1960s, the chemical industry was a bright, young industry that captured the hopes of its age, and inspired sparkly TV programmes - aka the UK's 'Tomorrow's World' - laying out the wonders of the latest plastic or man-made fibre.
By the 1990s, after more than a decade under attack as an environmental polluter, leading figures within the industry argued that it had effectively lost its 'licence to operate'. In the public's view, the chemical industry was an undesirable industry.
Sight had been lost of the industry's worth in supplying the materials, ingredients, and drugs in which our modern life-style - and life-span - are rooted. What was universally perceived was that chemicals was a dirty and even, in the view of many, a morally reprehensible industry.
A swerve in public opinion of this order is as costly as it gets. When it comes to graduate recruitment, industries with a dodgy reputation don't get first pick ahead of the 'good guys'. They don't get good press. They get isolated, and disheartened.
And there isn't any reason to let this happen.
Right now, steam is gathering behind the idea that the food industry delivers poor nutrition and thus ill-health.
At base, it is a widespread presumption that processed foods are inherently, and always, less nutritious than unprocessed foods.
This makes for some real grounds for attacking the value of the processing.
On its back foot, the low-research (by Bain's count) food industry, is tweaking out salt, fat and sugar. But cutting out the bad is not the same as adding something good.
Low-fat snacks aren't selling well either.
But probiotics are.
In dairy, products with added probiotics, cholesterol-lowering plant sterols, and vitamins account for all the sector's growth - sales of probiotic 'little bottles' grew by 52 per cent last year, according to Euromonitor, while sales of plain and natural yoghurts fell almost 2 per cent.
If consumers believed more regularly that purchasing processed food offered real health benefits, the food industry would take on a different hue: most especially in the eyes of an aging populations facing chronic disease for a significant part of its lifetime.
And the door is open.
A law proposed by the European Commission in 2003, and expected to reach its second parliamentary reading next year, will establish a list of approved 'health claims' allowing companies to spell out the good their products do to our bodies, where proven.
"Eating 3g of omega-3 fatty acids weekly, as part of a healthy lifestyle, helps maintain heart health", could be one of these.
Early adopters are already making such claims thanks to the investment of ingredient developers in clinical trials showing the health benefits.
Under the forthcoming regulations, it will also be possible to claim - with the necessary scientific evidence - that foods help reduce the risk of a specific disease, a first for most member states.
Too bad for the legislators if this footwork does nothing to draw mainstream 'wonderfoods' from an industry now earning its laurels as an innovation backwater.