"Tell me what you eat," said the French gastronome Jean Anthelme Brillat-Savarin in 1825, "and I'll tell you what you are." Things were so much easier then. Judging by what we put on our plates today, we have become a mightily confused bunch of people.
The central question of Hamburgers In Paradise is this: would Eve, were she around today, tempt Adam with a hamburger, an apple from a genetically modified tree, or a fair trade banana for which she had cycled to the stall and carried home in a paper bag? Today, all but a very few foods are seen as sinful.
Eating, says Louise O. Fresco, former assistant-director general at the Food and Agriculture Organisation of the UN, has turned into an ethical minefield.
Should we serve beef when cows emit greenhouse gasses of the worst kind? Is it immoral to buy jet-set fruit and vegetables? Should sugar be banned? Should sugar be taxed? Might genetically modified crops be a good thing? Should we eat beetles? (Apparently we already do.) How much should the state interfere with our larders?
The questions are endless, and if you are hungry for bite-sized answers, then Hamburgers In Paradise, the product of decades of research into the foods we eat and why, is not the book for you.
Understanding what we eat, suggests Fresco, is about making connections. Behind every bite lies a chain of supply linking consumers back through retailers and manufacturers to farmers. But what we eat also connects to climate change, big business, agriculture, biodiversity, GMOs, deforestation, cheap labour, social class, population growth, religion - everything, really. Jews are asking whether products made with transgenic crops are kosher. Catholics are still waiting for the Vatican to adopt a firm position on biotechnology. As far as Muslims are concerned, if genetically modified food meets the halal requirements, it need not be rejected on religious grounds.
In this painstaking study, Fresco has piled her plate high, with weighty and sometimes unwieldy chapters ranging from ecosystems and aquaculture to allotments in Amsterdam and the symbolism of bread.
"This is the kind of book that can never really be finished," she explains in her introduction; it should really "have an endless bibliography"; each chapter "could have grown into a book in its own right".
Because Fresco does nothing to contain or control the endlessness of her subject, Hamburgers In Paradise is hard work for the reader. So, too, is her decision, in the interests of fairness, to consider every issue from every angle rather than to pursue a single line of argument.
Take hamburgers, to which she returns throughout. On the one hand they are "ideological evidence of Western domination", "a symbol of greed" and of "everything that causes friction". On the other, they are a sign of social and cultural unity: we bond over burgers, reliable and changeless. But they are also the food of the lonely: burgers are eaten by people by themselves, in haste and on the road, away from the warmth and sociability of the family table.
As well as the continuation of traditional values, burgers also represent their breakdown.
Following Fresco's thought is like playing both sides in a ping-pong match, and the occasions on which she states an opinion, or reveals her own dietary decisions, come as a blessed relief.
In the chapter on meat, we learn that she eats meat and fish only in socially unavoidable situations, because respecting human relations is as important as respecting animals, and has a yoghurt every day because it sustains the dairy industry.
Although in the past 50 years we have destroyed tropical forests, entire plant species and large parts of the polar regions, we have also brought to an end centuries of food scarcity, for some people at least. We have reason, Fresco concludes, to be optimistic about feeding forthcoming generations in a sustainable and healthy way: even hamburgers have become healthier, with reduced fat and salt.
"Eve's paradise," she hopes, will be a world in which courage and curiosity combine with "a desire for knowledge" and "social responsibility" about our food.
The chances, some might say, look slim.
Hamburgers In Paradise
by Louise O. Fresco
(Princeton university press, US$39.50)
- Canvas, Telegraph