In case the whole angle of this blog series isn’t totally clear from its title, Zero-a-day, let me start off by underscoring once again the basic premise: humans have no requirement for dietary carbohydrate.
So I’ve looked at fruit and fructose, and now I’ll have a quick look at vegetables, although – spoiler alert! – you now know I’m going to conclude that there’s no more need to eat vegetables than there is to eat fruit.
Tell me if you ever see a broccoli plant scampering up a tree in order to escape its natural predators. Or a lettuce. (Although broccoli didn’t even exist until it was bred about 2,500 years ago, a mere pulse in the human timeline). While plants and trees want animals to eat their fruit, if they bear any, in order to propagate their seeds, they don’t want animals to freely eat their bodies, because death of species.
Most plants, therefore, are to a greater or lesser extent toxic. Many humans, for example, react badly* (*need to let their bowels explode into the nearest porcelain receptacle) to members of the nightshade family – peppers and aubergines, mainly. Many vegetables require cooking to destroy the toxins – potatoes, for example. (I’m not going to talk about legumes today, peas, beans, lentils etc, which are not veggies; that’ll be for another blog, as will grains).
Let’s be charitable though, and accept that humans have eaten vegetables in some form for probably tens of thousands of years, and today cooked vegetables have low or negligible toxin levels. Since they are relatively filling (lots of fibre) and low in carbs, they must be ok mustn’t they? They stop us getting cancer and heart disease and stuff don’t they? After all that is the whole basis of this 5-a-day thing, isn’t it (and nothing at all to do with selling more produce).
Dietary expert Dr Georgia Edes looked at the 762 studies on vegetables available via PubMed and found just 38 that attempted to evaluate whether vegetables had beneficial effects on our health (most of the others worked from the assumption that vegetables were necessary and focused on getting people to eat more of them). 31 of those 38 clinical studies, unfortunately, were not able to provide evidence of any health benefits from eating vegetables because they all failed to exclude other factors: some looked at eating fruit and veg; some made changes to several lifestyle elements as well as vegetable consumption, such as reducing refined carbs or smoking. Hang on, then what about the seven other studies? Six of them came up ‘negative’ – ie the hypothesised benefit of the study failed to materialise. Edes concludes that, while there may be no harmful effects from eating veggies, there is no scientific evidence – yet – that they have any positive effect.
This is by necessity a brief overview to keep the zero-carb message pumping out into the blogosphere, but in my next instalment I’ll look at whether the touted ‘good’ content of veggies, like fibre, antioxidants and vitamins, make them worth eating. Until then, grill some bacon (streaky, for the extra fat), fry some eggs and enjoy.