Tim Spector, an epidemiologist and co-founder of the ZOE nutrition study, wants to change the way people think about food. His 2015 book The Diet Myth popularised the idea that each of us has a unique and constantly changing gut microbiome that is crucial to our health. Spoon-Fed, in 2020, exposed diet misinformation. Food for Life, at over 500 pages, overlaps with these but offers more information than ever before. It aims to think about food for “our individual health, the health of our society and the health of our planet”. It’s complex, hard to digest and obviously good for us, like an enormous portion of fibrous vegetables, well balanced with spices.
Once you wrap your head around the microbes in our guts, which need a varied diet themselves in order to process the food that makes us healthy, much of it seems like common sense. Eating a wide range of plants keeps you well – 30 a week is ideal, including seeds, nuts, herbs and spices. “Ultra-processed foods” (UPFs) – a “heady, addictive mix” that makes us “fatter but less nourished”, are bad. Anything that claims to be a “superfood” is probably a con.
Other findings seem counterintuitive, but are often deliciously reassuring. Two cups of Americano coffee provide more fibre than a banana. You can reheat rice; unopened mussels won’t kill you; and eating meat doesn’t give you cancer (though “replacing 30% of traditional burger meat with mushrooms or fungi would be the equivalent of taking 2m cars off the road”). Some sources of nutrition are more beneficial together, like corn with beans, or “a glass of red wine daily with friends”. Replacing sugar, salt, fat and gluten with weird and untested chemicals is usually pointless and probably dangerous, and the 1980s advice to change butter and cream for margarines and vegetable oils was “one of the biggest health scandals ever”.
Appealingly, Spector writes as a food lover. He’s comically keen on kimchi, kombucha and sourdough bread – in fact, fermented foods are manna to our friendly microbes, including the cacao beans in good-quality chocolate. But he’s sometimes frustratingly understated when it comes to the politics – and finances – of food. Our choices are “a puzzle of availability, convenience, taste and education,” he admits, while cheerfully recommending that cheap UPFs and sugary children’s yoghurts “should be avoided”; that people should “choose organic, grass fed and whole milk” and “good honey from your local beekeeper”; and that “the tenfold increase in price” is the way to pick the right extra virgin olive oil.
However, his aim in this book is not to give advice. Our gut microbiomes are so different that, in human studies, there is an “eight- to tenfold variation in individual insulin, blood sugar and blood fat responses to the same meals”, and so every person’s ideal diet is different, and should be based on sensible choices from a position of knowledge.
Food for Life is a feast of that knowledge. It contains so much information that it’s impossible to process by reading it from start to finish, but bullet-pointed tips at the end of each chapter and an appendix of food tables make it a valuable reference book to keep on a kitchen shelf.
• Food for Life by Tim Spector is published by Jonathan Cape (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply.
