杏吧原创

NOW, I realise my lifelong fascination with how the crops that sustain humanity today were domesticated in the ancient past isn鈥檛 shared by everyone. So I was excited to see some classic examples of before and after pictures of familiar fruit and veg popping up on my Twitter feed a few years ago. These showed the sometimes stark differences between the supermarket staples that are familiar today with the wild relatives they were originally derived from.

Imagine my surprise when these photographs 鈥� normally confined to ethnobotanical textbooks 鈥� started to appear on other social media platforms, then blogs and eventually newspapers, used to support a claim that today鈥檚 crops are inherently lower in nutrition, and even dangerous to our health.

According to this argument, today鈥檚 crops 鈥� from carrots to bananas 鈥� have been altered so far beyond their natural state that they are now essentially bags of sugar, with a similar effect on our bodies. These images are enough to emphatically demonstrate this, according to proponents. But is a plant鈥檚 appearance a reliable guide to its nutritional value over the centuries? Let鈥檚 walk through the evidence together.

Perhaps the most striking visual used to illustrate this claim is that of an Italian Renaissance painting containing a watermelon by Giovanni Stanchi. With swirls of white in its light pink flesh, it does look rather different to the typical bright crimson varieties popular today. Yet, the reality is that even today, watermelons come in many colours, from canary yellow to the palest white, many of us are just most familiar with the red kind.

Indeed, if you are a fan of Italian Renaissance art, or, like me, simply have access to a search engine, you will see that there is also a famous painting of a red watermelon from the exact same period by another Giovanni (Battista Ruoppolo), which is rather a fly in the ointment of this argument.

鈥淲e should be investigating what happened to all the unicorns that mysteriously aren鈥檛 around anymore鈥�

The image comparison requires carefully selecting a single historical image and using it as a universal benchmark for 鈥渂efore鈥� and setting it off against a similarly selected image from the present, which isn鈥檛 very scientific.

Can colour even be a guide to the nutritional value of a fruit in the first place? In terms of sugar, fibre, most vitamins and minerals, the short answer is no. However, when it comes to phytonutrients, which are often pigments, the answer is yes, maybe.

For example, watermelons are given their red hue by antioxidants like lycopene and beta-carotene. This ironically means that all this before and after comparison really suggests is that the white and pink Renaissance fruit was probably lower in these beneficial compounds than the modern red form.

Last but not least, are artworks from the past an accurate enough vision of reality to be used for scientific comparison? We don鈥檛 know, for example, that Stanchi鈥檚 painting was of a ripe watermelon. These fruits start out life having pale flesh that only gradually turns red upon ripening.

Even if it was ripe, it is presumably possible that the colours of the painting we see today aren鈥檛 those the artist used, as pigments in paint can degrade over time.

But perhaps most simply, if we are using depiction in Renaissance paintings as a foolproof barometer for reality, as opposed to artistic impression, I don鈥檛 know why we are wasting time talking about fruit and veg when we should be investigating what happened to all the unicorns that mysteriously aren鈥檛 around anymore.

What non-botanists may not know is that while crops like today鈥檚 carrots, bananas 鈥� even watermelons 鈥� may be rather different from their wild ancestors, this is by no means universally true for all crops.

If you put the wild ancestors of apples or blueberries in crates at a farmer鈥檚 market, I doubt anyone would notice. The same would be true with some of the most ancient cultivars of dates and grapes 鈥� which happen to also be some of the fruit with the highest sugar content. Their appearances really haven鈥檛 changed that much in millennia.

The examples we see of radical transformations are used to illustrate enormous changes that breeding can create, but show extreme examples, not typical ones.

Does it frustrate me that extracts from botanical textbooks are being used to justify populist diet narratives with little basis in scientific reality? Yes and no.

Of course, the claim that fruit and vegetables are the same as sugar is as inaccurate as it is irresponsible. But without the viral popularity of these myths, would we have an opportunity to address people鈥檚 concerns and talk to them about the history of crop domestication? Perhaps not.