What we forget is that, as omnivores, we are extremely gifted at changing the way we eat to accommodate different environments.

My premise in First Bite is that the question of how we learn to eat - both individually and collectively - is the key to how food, for so many people, has gone so badly wrong. The greatest public health problem of modern times is how to persuade people to make better food choices.

Many people have absorbed the lesson from childhood that vegetables and pleasure - and more generally, healthy food and pleasure - can never go together.

The way we eat is not a question of worthiness but of routine and preference, built over a lifespan.

There are hundreds of millions of individuals who somehow swim against the tide of the dysfunctional modern food supply and feed themselves pretty well.

Dopamine is one of the chemical signals that passes information between neutrons to tell your brain that you are having fun.

A survey of more than three hundred international policymakers found that 90 per cent of them still believed that personal motivation – aka willpower – was a very strong cause of obesity.6 This is absurd.It makes no sense to presume that there has been a sudden collapse in willpower across all ages and ethnic groups and each sex since the 1960s. What has changed most since the sixties is not our collective willpower but the marketing and availability of energy-dense, nutrient-poor foods.

Then I realised the very question I was asking was wrong. The whole point is that in the 1960s, there was no such thing as an average eater across most countries, just lots of specific and wildly divergent patterns of eating. Back then, there were maize eaters in Brazil and sorghum eaters in Sudan. There were steak and kidney pie enthusiasts in Britain and goulash devotees in Hungary. But it made little sense to ponder how a globally average person

The danger of growing up surrounded by these endless sweet and salty industrial concoctions is not that we are innately incapable of resisting them, but that the more frequently we eat them, especially in childhood, the more they train us to expect all food to taste this way.