Alex Renton imagines what two families - one rich, the other hard-up - might be eating in the future.
Predicting what we will eat in Britain in 2035 comes down to how gloomy you are about the future. Will stagnant growth have pushed us down the list of rich nations so far that we can't import any foods any more? Or will new energy sources and acceptance of food bio-tech mean that 3-D food printers will be pumping out nutritionally enriched burgers and sushi in all our homes? Will climate change mean land in Britain has to be devoted to crops, not meat, to keep 70 million of us fed?
The hard-up family
We're growing as much food as we can in the back garden. Food costs are using nearly half the family income, compared with just 12% for our grandparents, so we throw away very little indeed.
The Food Ministry has decreed that refining flour wastes too many vitamins and minerals and has banned white bread (as Britain did in the Second World War). Wheat flour prices rocketed with the collapse of arable farming in India, southern Russia and the US, so Britain no longer imports any.
Dad won't eat "Frankensteaks" - he'd rather have a farmed locust fry-up - but the rest of the family eat "algae-farmed" bio-reactor-grown meats (we don't like the stuff made from proteins recovered from sewage).
It's spuds every day of the week: even the pasta's made from potato flour. Potatoes are the staple carbohydrate, though experts worry about our dependence on this one crop - reliance on potato alone led to the Irish famine that killed a million people. GM delivered a potato that resisted blight, but new diseases keep appearing and none of the old varieties survive.
The richest part of the world - south and east Asia - eats all the rice they produce, so importing is expensive and attempts to grow rice in the new wetlands of the Thames estuary haven't paid off. The rice we buy is made from reconstituted potato or barley. By law, all brands contain nano-sized capsules of vitamins and nutrients.
Cheese and butter
There's little animal farming in Britain, except for dairy. Cows are an efficient way of turning vegetable matter into animal fats, so long as there's enough water. Our city street has its own small herd of GM cows, co-operatively managed in the pasture made by knocking through the gardens. Like our medieval ancestors, we now get most of our necessary fat and protein from milk, cheese and butter.
Carnivorous fish are a rare treat. Even the most advanced GM salmon in the farms still need to consume three grammes of other fish to produce one of its own. So we eat vegetarian fish, grown in solar-heated, aquafarm sheds - developed from tropical varieties such as tilapia and catfish, and modified with lemon, tomato or herb genes to cover their basic muddy flavour. By law, all have Omega-3 added to their diet.
Nano-encapsulated food is mostly for rich people but the government subsidises programmable fruit for children. Data from the monthly blood test all citizens are required to undergo feeds straight to the fridge, whose computer chooses and triggers molecule-sized capsules containing different vitamins and minerals. You can choose what flavour the fruit comes in.
Coffee and tea
Real tea and coffee are Christmas treats. But the synthetic flavours are so convincing now - the adverts say they use the actual chemicals that were in the beans and leaves.
The well-off family
Some of the rich have turned the art of eating over to technology, allowing their diet computer to programme their nutrition using results from blood, faecal and serotonin-level tests. Liquids and solids for ingestion are automatically manufactured through 3-D printing in what used to be the kitchen. But imported, real food - whether it's genuine wheat pasta, chocolate, pulses, or fruit and veg ripened in the sun - are popular. "Wild" foods, such as tuna, can only be had on the black market .
The smart fridge
Not only does our fridge tell the supermarket what needs to be delivered, it's continually monitoring the state of the food, and tending it. Nano-level additives (chemical machines at sub-molecular level) monitor bacteria and viruses in the food. They can alert the kitchen computer when food needs to be eaten and act to neutralise anything harmful.
Packaging lets us know what's going on inside the food trays, but even "fresh" food is lasting far longer than it did in our ancestors' days, because nano-clay films prevent all oxygen reaching foods. Nano-technology attaches beacons to bacteria, and they glow to warn you that they're in the food.
We won't touch artificial meat. But a carnivorous habit is wildly expensive and some of our friends find it distasteful: "Imagine killing a lamb!" they say. Our teenage son complains that our meat habit is "responsible for more greenhouse gases than the transport system". So when we do enjoy our hand-reared, real sirloin of Aberdeen Angus beef at £300 a kilo, we do it with friends who understand.
We worry about our weight and health, so most of the food we eat is designed to give us the illusion of having eaten more than we have. The old-fashioned system delivers fast-expanding fibre in capsules straight to the stomach, making you feel full. But when we are on diets, we can eat our fill of fatty foods because the oils that make them are specially adapted to be made largely of water. Some foods even come able to deliver the hormones that signal to the brain's pleasure centres that enough has been eaten - we can pre-programme our strawberry gateau so we feel full to bursting after just one slice.
The new de-toxed wines are a great boon. Encapsulation of chemicals means we can programme our wine to release agents that will neutralise the alcohol in our bloodstream at a specific time. So a drinker can go from tipsy to sober in a few minutes and go back to work or drive home safely. Plus, if you ask them to, you can programme the drinks to release sugars and analgesics to deal with the hangover before you've even noticed it.
Chocolate, coffee and tea
The countries that produced these crucial luxuries are those that climate change has hit hardest. Wars over water resources in India and West Africa have all but destroyed the tea and cocoa business and only the very rich can still afford them. A genetically modified coffee has been produced on Bodmin Moor, but production is limited. And no one actually likes the taste.
What will we be cooking up in the future? Photograph: Hill Photographers/Getty