While 75% of us know that we should be eating 5 portions of fruit and veg daily, only one third of us follow through. Philip Boucher-Hayes meets the people of Cloughjordan Eco Village who grow their own food, tests schoolchildren on their knowledge of fruit and vegetables, puts the squeeze on the current craze for juicing, and finds out why our aversion to bitter tastes is narrowing the range of fruit and veg on supermarket shelves