Christopher Gardner
Allen & Unwin (UK), 15 October Simon Element (US), 13 October
If you are one of the tens of millions of people who watched the award-winning Netflix documentary series , you’re already somewhat familiar with Christopher Gardner’s work. The show followed four pairs of identical twins as they participated in an experiment – a , not a TV one – to test the health effects of switching from a standard US diet to a vegan one. Unsurprisingly, the twins who went vegan for eight weeks saw health improvements across the board.
So far, so vanilla. That’s what nutrition scientists do – they run experiments on the health benefits (or otherwise) of diets, foods and individual nutrients. But Gardner isn’t a cookie-cutter nutrition scientist. Yes, he is a at Stanford University in California, which certainly qualifies him to write a book like . But he brings other things to the table, too. He started his academic life as a philosophy major, worked in restaurants for six years and is an accomplished chef. This peripatetic CV gives him a refreshingly different take on the question in the subtitle of his book: What to eat and why.
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Gardner found that food-adjacent issues were actually strong motivators of positive dietary change
If you’re expecting a prescriptive answer to that question, you won’t find it here. Gardner’s stated aim is to teach us how to think about food, not tell us what to eat. That obviously includes understanding which foods and diets are healthy, but also the other factors that drive our food choices: pleasure, values and culture. The result is a holistic picture that goes above and beyond the narrow questions that dominate nutrition science.
Out of methodological necessity, scientists ask constrained questions such as “does consuming X at a dose of Y for a duration Z help this specific population to improve A or B?” X might be a nutrient such as sugar, or a specific food such as red meat.
But that isn’t how humans eat in the real world. We don’t just consume nutrients and specific foods in isolation; we eat meals and snacks, and choose what to eat and what not to eat for a variety of shifting reasons. We indulge sometimes, and generally find it hard to stick to diets.
In any case, people’s food choices are rarely dictated by discoveries about health harms or benefits. Gardner recounts in his book how, early in his career, he took the orthodox approach to nutrition science, studying single nutrients, foodstuffs and diets and the health effects of eating them. He dutifully published his findings in journals and presented them at conferences, but the real-world impact of his discoveries was negligible. Almost nobody – not even the people involved in the study – changed their dietary habits as a result of his work.
What was he doing wrong? In 2004, he accidentally discovered the answer. He and a colleague started teaching a class at Stanford focusing on food-adjacent issues such as the environment, animal welfare and social justice. He found these were much stronger motivators of positive dietary change than any amount of health-oriented nutritional advice.
Students who didn’t care about the negative health impacts of, say, red meat, often decided to cut down on beef or give it up entirely for other reasons, such as its impact on the environment, its poor animal-welfare record or the working conditions on farms and in slaughterhouses. The fact that these values-driven changes also align with healthier choices is just a happy accident. Gardner calls this “stealth nutrition”.
That’s not to say that there is no useful health advice in the book. Gardner explains that, despite the impression of endless controversies and U-turns, there is actually a high level of consensus in nutrition science about what constitutes an optimal diet. He boils this down to the “big four” and the “solid six”. The four are near-universally agreed principles for healthy eating: include vegetables and whole foods in your diet, and limit or avoid added sugars and refined grains (such as white rice and products made with white flour). The solid six are food groups that a large majority of nutrition scientists agree are key to healthy eating, though all have a handful of detractors: legumes, fruits, nuts, eggs, fish and yogurt.
In the second part of the book, Gardner sets the record straight on 11 nutrients and foods that are currently rife with confusion, hype and mis- or disinformation. These include protein, cholesterol, seed oils, plant-based meats, sugar and ultra-processed foods. On protein, for example, he says you are almost certainly getting more than enough even if an influencer is telling you to eat more. I didn’t expect to learn a lot here, but I did.
For his final act, Gardner serves up a recipe for what he calls “the philosopher-scientist’s kitchen”. It’s essentially a cookbook explaining how to apply the lessons of the preceding chapters. Everything sounds tasty, especially his guide to turning salad into a meal. Take a leafy green base and add crunchy vegetables, pulses, nuts, olives, avocado and a dressing. As he says, “unapologetically delicious, and infinitely variable”. There is also a helpful appendix explaining the various scientific methodologies employed by nutrition scientists. Mission accomplished: this is how to think about food and nutrition.
What not to eat
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Another new big-picture take on the matter is provided by , director of the Food is Medicine Institute at Tufts University in Massachusetts. In Mozaffarian similarly argues that we have fundamentally misunderstood what healthy eating is. The food system has spent decades striving to make unhealthy processed food slightly less unhealthy, when it should, he writes, have focused on making minimally processed and nutrient-rich food the easiest, cheapest and most desirable choice. It’s a somewhat predictable conclusion, but the book’s strength is explaining how we painted ourselves into this corner, and how to get out of it.
Both of these books will change how you think about what you buy, cook and eat, and liberate you to enjoy a rich, healthy and delicious future.
Three more great reads on how to eat healthily
A classic from 2008 in which journalist and activist Pollan cuts through the crap of what he calls “nutritionism” to deliver a simple and oft-cited rule of thumb for a healthy diet: “Eat food. Not too much. Mostly plants.”
Lieberman, an evolutionary biologist, examines popular diets and concludes that there is no such thing as a universal optimal eating pattern, apart from the four pillars of good nutrition, as Gardner writes (see main review).
The Salad Bowl by Nicola Graimes
This is a recipe book, not a science book, but I recommend it to anyone who wants to eat more delicious, nutritious whole foods. As Gardner says in his book, salad is a meal!
Graham Lawton is a former Â鶹´«Ă˝ staff writer
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