“Nutritionists don't stop there, because they can't: they have to manufacture complication, to justify the existence of their profession. These new nutritionists have a major commercial problem with the evidence. There's nothing very professional or proprietary about 'Eat your greens,' so they have had to push things further. But unfortunately for them, the technical, confusing, overcomplicated, tinkering interventions that they promote - the enzymes, the exotic berries - are very frequently not supported by convincing evidence.”

“Two large trials of antioxidants were set up after Peto’s paper (which rather gives the lie to nutritionists’ claims that vitamins are never studied because they cannot be patented: in fact there have been a great many such trials, although the food supplement industry, estimated by one report to be worth over $50 billion globally, rarely deigns to fund them). One was in Finland, where 30,000 participants at high risk of lung cancer were recruited, and randomised to receive either ß-carotene, vitamin E, or both, or neither. Not only were there more lung cancers among the people receiving the supposedly protective ß-carotene supplements, compared with placebo, but this vitamin group also had more deaths overall, from both lung cancer and heart disease. The results of the other trial were almost worse. It was called the ‘Carotene and Retinol Efficacy Trial’, or ‘CARET’, in honour of the high p-carotene content of carrots. It’s interesting to note, while we’re here, that carrots were the source of one of the great disinformation coups of World War II, when the Germans couldn’t understand how our pilots could see their planes coming from huge distances, even in the dark. To stop them trying to work out if we’d invented anything clever like radar (which we had), the British instead started an elaborate and entirely made-up nutritionist rumour. Carotenes in carrots, they explained, are transported to the eye and converted to retinal, which is the molecule that detects light in the eye (this is basically true, and is a plausible mechanism, like those we’ve already dealt with): so, went the story, doubtless with much chortling behind their excellent RAF moustaches, we have been feeding our chaps huge plates of carrots, to jolly good effect. Anyway. Two groups of people at high risk of lung cancer were studied: smokers, and people who had been exposed to asbestos at work. Half were given 3-carotene and vitamin A, while the other half got placebo. Eighteen thousand participants were due to be recruited throughout its course, and the intention was that they would be followed up for an average of six years; but in fact the trial was terminated early, because it was considered unethical to continue it. Why? The people having the antioxidant tablets were 46 per cent more likely to die from lung cancer, and 17 per cent more likely to die of any cause,* than the people taking placebo pills. This is not news, hot off the presses: it happened well over a decade ago.”

“What can you do? There's the rub. The most important take-home message with diet and health is that anyone who ever expresses anything with certainty is basically wrong, because the evidence for cause and effect in this area is almost always weak and circumstantial, and changing an individual person's diet may not even be where the action is.”

“If I was writing a lifestyle book it would have the same advice on every page, and you’d know it all already. Eat lots of fruit and vegetables, and live your whole life in every way as well as you can: exercise regularly as part of your daily routine, avoid obesity, don’t drink too much, don’t smoke, and don’t get distracted from the real, basic, simple causes of ill health. But as we will see, even these things are hard to do on your own, and in reality require wholesale social and political changes.”

“Homeopathy pills are, after all, empty little sugar pills which seem to work, and so they embody [..] how we can be misled into thinking that any intervention is more effective than it really is.”

“Randomisation is not a new idea. It was first proposed in the seventeenth century by John Baptista van Helmont, a Belgian radical who challenged the academics of his day to test their treatments like blood-letting and purging (based on ‘theory’) against his own, which he said were based more on clinical experience: ‘Let us take out of the hospitals, out of the Camps, or from elsewhere, two hundred, or five hundred poor People, that have Fevers, Pleurisies, etc. Let us divide them into half, let us cast lots, that one half of them may fall to my share, and the other to yours … We shall see how many funerals both of us shall have.”

“As it is a major component of blood, water is vital for transporting oxygen to the brain. Heaven forbid that your blood should dry out.”