In the “Human Health and Welfare” section under The College, David Kennedy, director of Leaf for Life, points out one of the great anomalies of many and perhaps most modern diets – and of diets for the past many centuries: humanity’s extraordinary neglect of green leaves. In the fast-food restaurants that are taking over the world leaves typically feature at best as decoration. Even in smarter restaurants and most pubs their presence is token (and they are commonly over-trimmed and over-cooked). Yet whatever side of the divide we are on – over-nourished or under-nourished – leaves should be key players in our diet.
Thus in the 1970s and ‘80s the great N W (Bill) Pirie of Rothamsted (then still enjoying the last magnificent years of its independent, unprivatized intellectual freedom) promoted leaf pulp, not simply as a source of micronutrients, but of protein. For leaves in general provide more protein per unit of land than any other form of vegetation, and much more of course than any livestock. The protein in cereals and pulses – the prime source of protein for human beings, by far – is created in the leaves. Cattle and sheep don’t create the protein that’s in their flesh; they process it from the proteins in the grass and browse.
Of course there are snags. Human beings don’t digest plant fibre in the way that dedicated microbe-assisted herbivores are able to do — which of course is why Pirie advocated pulping. On the other hand, westerners would benefit from foods with higher concentrations of micronutrients but with far lower concentrations of calories. Either side of the nutritional fence, appropriate leaves appropriately treated are very good news. Many of them, too, are among the supreme gastronomic delights. So they should be right at the heart of all cuisines – as they surely were for our ancient ancestors. But on the whole they aren’t.
The message from Leaf for Life needs to be heeded. If we took leaves seriously, we could shift the whole balance of agriculture — notably, towards horticulture. The implications — social and economic, as well as the nutritional — are enormous, and are almost all to the good.