How many Diet Cokes are too many Diet Cokes? And if you sell too many, should you get an ESG downgrade or have a health offset of some kind? A nutri-credit perhaps? It would be bought from, say, the National Health Service in the UK or a gut-health education group.

That’s not as ridiculous as it sounds, particularly if you are a big company going after a top ESG rating. These days you can mitigate all manner of the ills you cause to society by stumping up a part of your profits for feel-good points: Airlines can buy carbon credits; builders can use biodiversity credits to offset their damage in woodlands and wetlands. So why not nutri-credits too?

The harm done by ultra-processed food  — and by extension those who produce it — to the health of the world is increasingly obvious. The last few months have seen a spate of books on the matter — think Ultra-Processed People: Why Do We All Eat Stuff That Isn’t Food… and Why Can’t We Stop? by Chris van Tulleken. Most nutritionists and doctors are firmly on the same page.

The message? UPF isn’t just a little bit bad for you. It’s terrible for you. It messes with your head, drives you to overeat and makes you fat; it contributes to our soaring rates of cancer, diabetes, heart disease and strokes — to early death all round.

A bottle of soda is photographed in Washington Thursday, Jan. 23, 2014. On Thursday, July 13, the International Agency for Research on Cancer, the cancer research arm of the World Health Organization, deemed aspartame, the world’s most widely used artificial sweetener, to be “possibly carcinogenic” to humans. Separately, a U.N. expert group assessing the same evidence said their guidance regarding safe consumption of the sweetener remained unchanged. AP Photo/J. David Ake, File

We have started eating substances that “can’t really even be called food,” says van Tulleken — “emulsifiers, low-calorie sweeteners, stabilizing gums, humectants, flavor compounds, dyes, color stabilizers, carbonating agents, firming agents and bulking — and anti-bulking — agents” just for starters. Yuck. You might think this is a matter for government; in the UK, diabetes alone now takes up 10% of the total NHS budget.

But if you are interested in ESG investing, you might also think that a full-on health crisis partly caused by the firms that are top holdings in almost all global portfolios would also be a matter for the vast sustainability teams now employed by all fund managers, particularly given the inbuilt regulatory risk. It doesn’t seem to be.

There is much emphasis on the E in ESG when it comes to food companies: carbon emissions (everyone has a net-zero pathway), much on biodiversity, pollution and, of course, the integrity of supply chains. Various subjects are also listed under the S — health and safety, diversity and inclusion and so on.

But sustainable food is not just about where it’s grown and who grows it. It’s also about what the final product does to the consumer. And you’d be hard-pushed to find a commonly used metric anywhere that measures the production of the kind of food that degrades health, overloads health services and cuts the productivity potential of nations (the rising number of people on NHS waiting lists is hardly helping the UK get ahead).

This is a very important S. There are some hints that the financial industry is getting it. A few UK fund managers have, as part of the Investor Coalition on UK Food Policy, complained about the government’s failure to create league tables of companies producing the most foods with the nastiest ingredients.

Activist group ShareAction has been having a go at the likes of Unilever Plc via its Long-term Investors in People’s Health engagement program. And at the Tokyo Nutrition for Growth (N4G) Summit in 2021, a group of investors asked that food and beverage companies develop a nutrient-profiling system to define what is and is not healthy.

So far this is very much all hat and no cattle. ESG investors need to tick boxes, and there is no consensus yet as to what those boxes might be — no harmonized, evidence-based ESG-nutrition metrics, and certainly none that the big food companies all use and disclose. Those that attempt measurement don’t do quite what we want.

The Access to Nutrition Initiative ATNI Global Index scores the top 25 manufacturers around the world, for example. But only 35% of the score comes from the products themselves (the rest is governance, labeling, marketing, etc). Nestle SA comes top, even after a 2021 report that more than 60% of its products don’t meet a “recognized definition of health.” Fat and fed-up consumers might have ideas about how to do this better.

We might say, for example, that having a certain percentage of sales from products with more than four ingredients; a shelf life of more than a month; or packaging that might upset the gut microbiome should be a bad box tick. In 2022, Nestle was rated AA by MSCI ESG Research. If what its products do to people rather than just the environment mattered as much to MSCI, then there would have been no “A’s” involved (unless an awful lot of nutri-credits were purchased, of course).

Consumers do care about these things. Searches for “Is Aspartame in Coke Zero?” rose by 4900% in the wake of the World Health Organization report suggesting the artificial sweetener is carcinogenic; an increasing number of fund managers insist they care too. So it’s time to think about all this properly — and to push for standardized mandatory disclosure from food companies. It is all very well (and obviously worthy) to devote time and effort to saving the planet. But if the companies you invest in are also responsible for the long-term decline in the health of the global population, who exactly are you saving it for?

Merryn Somerset Webb is a senior columnist for Bloomberg Opinion, covering personal finance and investment, and host of the Merryn Talks Money podcast.