For years, fibre was the nutritional equivalent of beige short-pile carpet. Practical, but a little bit off-putting, it summoned up visions of stewed prunes, boiled cabbage and the F Plan, a 1980s diet that involved eating your body weight in All-Bran. More recently, nutrition has been about sexier things: superfoods, biohacking and supplement stacks, rather than boring old roughage. If you talked about fibre, you were really talking about poo, about going to the loo regularly.