Next month, the UN hosts the second International Conference on Nutrition in Rome. The first ICN was back in 1992, and a lot has happened since then. The world’s got fatter. soft drinks and fatty, salty, sugary, unnecessarily processed foods have spread globally.

These are signs of rising incomes in previously poor countries, say supporters, who go silent over food’s impact on Health. Which developing country can afford to pay the costs of type 2 diabetes? We are horrified at Ebola exposing weak public health infrastructure and cultures but, sad to say, diet’s impact is vast compared with Ebola.

Evidence of diet’s environmental impact has also grown since 1992. More meat and dairy are consumed as people get richer. Intensive agriculture is the world’s major water user.

“There are now more people obese in the world than hungry”

ICN2 thus meets when evidence suggests public health advice needs to be integrated into environmental advice. Above all, we need new cultural advice. Brazil is showing the way. Its Ministry of Health guidelines call for simpler diets and ask consumers to be wary of any food being advertised.

Food industries need to realise that the 20th-century experiment with endless eating is running out of road - and wise heads in food industries know this. They know unless consumers change, food’s negative impact will rise not fall. So who will tackle the runaway food culture?

These questions send policymakers diving for cover. Consumers are the new gods, and efficiency is whatever helps supply chains bow before them.

One might think ICN2 would be an occasion where such issues are discussed and new, appropriate courses charted. But the signs are that sustainable diets are not on the agenda; the focus is on under-consumption and how agriculture must intensify still further, as though demand is fixed. A familiar drama thus unfolds: disappointed scientists and NGOs, weary government officials, bruising big battalions, and rhetoric about food poverty.

In truth, there are now more people obese and overweight in the world than hungry. And waste continues. These problems are signs of the clear need for more sophisticated policy frameworks.

Tim Lang is professor of food policy at City University, London