Ideally, I’d love to be able to shout the content of this book from the rooftops, but then nobody would buy it. Instead, here is a review and a peek at some of the seventy nutrition myths that Martijn Katan thoroughly and humorously debunks in his new book Voedingsmythes – Over valse hoop en nodeloze vrees (Nutrition myths – About false hope and unnecessary fear). It comes out today.
Myth 2: If you eat too little, your body goes into famine mode. Myth 14: You have to eat slow carbohydrates; rapid carbohydrates are unhealthy. Myth 61: Healthy food is expensive. This is just a small selection from the seventy often-heard statements that Emeritus Professor in nutrition, Martijn Katan, debunks in his new book. The myths each have their own chapter and are grouped into eight topical sections: – Weight loss
– Dairy and eggs
– Poison and cancer
– Fruit and vegetables
– Health out of a jar
– Natural and healthy
It’s about not doing certain things
Each chapter has an overarching conclusion that comes down to the idea that most of what you read or hear about nutrition can best be disregarded. Broadly speaking, the ‘boring’ advice remains true: eat a variety of foods in moderation; in other words, not too much, and not too fatty, sweet or salty. From the age of fifty, take a vitamin D tablet daily, and other than that, the advice is mainly not to do things, such as smoke or drink alcohol. But on a detailed level, Katan provides a huge number of fun facts as well as background information that helps you to separate the wheat from the chaff. For example, what the story is with milk, organic food, the Paleo diet, coconut oil, E numbers, etc.
Katan thinks differently about vegetables
In the introduction, Katan says: ‘Most of what I’m here to tell you has been long known in the scientific world and is not controversial. It’s only about fruit and vegetables that I differ from my colleagues in my views. In my opinion, there is insufficient proof to suggest that fruit and vegetables decrease the risk of cardiopulmonary disease and cancer.’
‘Scientists can sometimes find it difficult to accept when they find no discernible effect caused by a supposedly healthy substance’
Katan believes that the many health claims about fruit and vegetables are exaggerated – they allegedly help to prevent cardiopulmonary disease, overweight and cancer. In myth 38, Nothing is as important as vegetables, he delivers a nice insight into how science works and what its limitations are. It is true that people who eat a lot of vegetables are eating more healthily than those who don’t, ‘but they are also more highly educated, richer, slimmer, eat less meat, smoke less, exercise more and faithfully show up for cancer screening.’ How are you supposed to establish precisely what it is that keeps them healthy? To answer this question would require running experiments in which tens of thousands of people ate either little or a lot of vegetables over a number of years. That is unlikely to happen. In addition, scientists can sometimes find it difficult to accept that they can find no effects of, for example, the supposedly healthy orange substance, beta carotene. They keep looking, claiming that the outcomes aren’t correct for one reason or another. Can you skip your fruit and vegetables in the future? Katan: ‘Vegetables also have undeniable advantages over meat and cheese: no animals have to be slaughtered, and plant-based foods are better for the environment. So keep eating them. But other things are just as important for your health.’
Healthy mayonnaise and unhealthy frankfurters As a scientist, Katan always remains critical, including where his own work is concerned. In an NRC column at the end of 2013, he cast doubt on his own previous bestseller Wat is nu gezond (2008, now in its 21st printing, 60,000 copies sold and a very useful reference). He noted in the column that nutrition science is temporarily in a state of upheaval due to a paradigm shift. Take mayonnaise, for example: in itself, a healthy product with many healthy fatty acids, little salt and harmless additives. But it makes your unhealthy frankfurter much more delicious, and because of that, you eat more of it. ‘We shouldn’t only measure the health effects of a product by the nutrients it contains, but also look whether you get fat from eating it. (…) We have to measure and tabulate the seductive power of ultra-processed food so that the government, parents and schools can take measures, but I don’t know how we should go about that. How do you turn calories, mouthfeel, odour, portion size, packaging and a hundred other factors into one weight gain score?
Cheap and healthy chilli con carne
To my knowledge, that problem has not yet been solved, but in his new book, Katan gives the best tips currently available for staying slim and healthy. Is there really nothing the book lacks? Well yes, in the recipe for a cheap and healthy chilli con carne (myth 61 Healthy food is expensive), to the tin of beans, tomatoes, tomato puree, onions, mince and chilli I would also add a scoop of cumin powder for the authentic Mexican flavour. And all those tins make me think about the hormone-disrupting substance BPA in the tin coating, but that also turns out to be a myth, according to Chapter 35 Bisphenol A (BPA) is dangerous for babies. Not so, and it also poses no risk to chilli eaters. It is a great book, upon which I feasted responsibly.
> Nutrition myths –About false hope and unnecessary fear by Martijn Katan appears 14 April 2016. 319 pages, € 19.95, Publisher: Prometheus & Bert Bakker.
Myth 56: Natural food is always the best
‘Natural’ and ‘healthy’ seem synonymous. But are they?
The National Poisons Information Centre receives calls from four or five GPs daily because a child has eaten ivy, yew, grape hyacinths or other poisonous plants. People can also fall victim to certain mushrooms. Plants contain toxins for good reason: they don’t want to be eaten. This is why their most delicious parts are full of poisonous substances. Take beans, for example. They form the most nutritious part of a plant and animals like to eat them. People learned early on that some of the toxins in beans could be deal with using fire. Raw soya beans contain lectins that damage our intestines, but cooking the beans properly puts the lectins out of action. Another way to deal with the toxins in the plants is to change their DNA by breeding or refining. Wild lima beans contain so much cyanide that one spoonful could kill you, but breeders have genetically altered the plant so much that there is no longer any cyanide in cultivated lima beans. Those are the lima beans we buy at the organic farmer’s market.
For tens of thousands of years, farmers, and nowadays expert breeders, have tried to rid plants of the ability to make toxins. Sometimes they succeed with the edible portion but not with the rest of the plant. For example, the leaves of the potato, tomato and aubergine plants are still full of toxic alkaloids.