And so, as with every New Year, we welcome the quinoa-packed saucepans, virtuous jars of coconut oil and the herbal remedies which, we hope, will push out the carbs and caffeine binges of last year. The supermarket queue displays a thousand promises of health, wealth and well-being from slim, smiling models. But in a world where a simple glass of red wine can have a thousand conflicting effects from self-declared health experts, what’s the real secret to longevity? Well, why not take a look …