There are few subjects more emotive, and dare I say political, than food and diet. Just reflect upon the billions spent in advertising all manner of food and beverages, mainly of the non-nutritious variety – chocolate, sugary breakfast cereals, crisps, cakes, coffee, tea, alcohol, as well as beauty products such as shampoos, face creams and deodorants containing nutrients like vitamins, or herbs such as aloe vera or jojoba oil.