On Tuesday evening, David’s Bookshop in Letchworth hosted a talk by botanist, writer and broadcaster James Wong on his new bestselling book. As usual James gave a lively and interesting talk in which he demonstrated a broad knowledge of the scientific data behind the ideas in the book. How To Eat Better is a cookbook with a difference. Inspired by scientific data, James discusses how to SELECT, STORE and COOK food in ways which maximise its nutritional value. The recipes are fresh and simple with old favourites like ‘One-Pot Mac and Cheese’ and new ideas such as ‘Blueberry and Chilli Cheese Toastie’ and ‘Double Sweet Potato Pie’. I rate my recipe books based on how many pages display the evidence of the meals I’ve made with them. So far for How To Eat Better it’s looking good – not only has it been fascinating reading outside the kitchen, but at least two pages are now indelibly marked with tomato juice and mustard – not bad for a book I bought this Tuesday!
Coming from a family of scientists (although I sit on the fence with a literary and horticultural background), some of whom work in science communication, I find James’ evidence-based approach to nutrition refreshing in a world where ever-changing sensationalist headlines inform many people’s food choices. Rather than beginning with nutritional rules and then searching for data with which to support these ideas, it seems sensible to start with the data and see what it tells us. I particularly liked the table explaining ‘The Hierarchy Of Nutritional Evidence’ which explores systematic reviews, clinical trials, observational studies, animal studies and test-tube studies considering the methodology of each type of research and the strength of the evidence each provides. This knowledge allows a greater understanding of the ways in which scientists reach conclusions, helping people ‘sift through fact and fantasy in the next nutritional headline’. I was also impressed, although not surprised, by the non-dogmatic approach to the selection, storage and cooking of the foods studied in the book. James explained that the methods suggested should be viewed as ways of ‘tweaking’ what we already do in the kitchen – small, practical changes rather than a radical overhaul of how we view our food.
Choose red chillies and peppers over green and yellow to up carotene and polyphenol levels by up to 5 times
The kids were fascinated by the idea that fruit and vegetables are living organisms which are affected by the chemical changes initiated by different storage and cooking methods. Although this seems like a rather obvious point, we do have a tendency to consider these foods as somehow unaffected by their environment once they are no longer growing on the plant or in the ground. I already keep our tomatoes out of the fridge as this allows the fruit to ripen, become sweeter and develop twice the levels of lycopene, but I wasn’t aware that the shape of a tomato is important in terms of its phytonutrient levels too. These chemicals are largely concentrated in the skin of the fruit, so baby plum tomatoes with their high ratio of skin to flesh, pack a denser phytonutrient punch than beefsteak tomatoes. The book also explains that lycopene levels almost double again upon cooking – another easy way to increase the nutritional value of these popular fruits.
The colour of fruit and vegetables is another interesting topic explored in some detail in the book. I love growing different varieties of colourful crops (‘Green Zebra’ tomatoes, ‘Purple Dragon’ carrots, ‘Kohlibri’ purple kohl rabi), so the fact that most colourful varieties (the book discusses pink grapefruit, purple cauliflower and black rice among others) contain higher levels of nutrients than their white counterparts means that growing these types of fruit and vegetable makes good nutritional sense as well as being engaging for both children and adults.
The darker the carrot, the more polyphenols it contains
Cooking is another area where science offers interesting data about our food and whether nutrient levels are higher (and more available for our bodies to absorb) when fruit and vegetables are eaten raw or cooked in different ways. Broccoli, for example, is better eaten raw if you are after higher levels of beneficial isothiocyanates as cooking destroys the enzyme responsible for producing these chemicals. However, a team at the University of Reading found that adding a tiny amount of powdered mustard seeds can reverse this process as they contain a heat-resistant form of the enzyme which allows the reaction to occur. Magic! And raw broccoli chopped finely and left for a couple of hours contains more isothiocyanates, making it even better for you. Unlike broccoli, evidence suggests that blueberries are more phytonutrient rich when lightly cooked in the microwave for 3 minutes.
Purple Sprouting Broccoli is best as fresh as possible
Some sections of the book confirmed what I already do in the kitchen (like rushing the purple sprouting broccoli in from the garden and lightly steaming it) whilst other information challenged my preconceived ideas about food (that buying local always means fruit and vegetables are better for you). But what is most refreshing about How To Eat Better is that it isn’t an instruction manual on better eating, but a way of transferring ideas based on scientific research into practical advice for the kitchen. To what extent you choose to adopt changes to selecting, storing and cooking food is up to you, but you’ll end the book more knowledgeable about the biology and chemistry behind your food. You’ll have a range of tasty, healthy recipes to inspire you to eat more fruit and vegetables however you decide to select, store or cook them and because James is donating all the royalties from the book to UNICEF, you’ll also have helped fight hunger across the world too.
Green tomatoes like ‘Green Zebra’ contain high levels of tomatine which may inhibit cancer cell growth
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If you’d like to read more of the book reviews in Write Plant, Write Place, you could take a look at the following articles:
Around the World in 80 Plants
The Paper Garden: Mrs Delany [Begins Her Life’s Work] at 72
RHS Plants From Pips and The Little Book Of Hygge