Jacques Peretti investigates how the concept of 'supersizing' changed our eating habits forever. How did we - once a nation of moderate eaters - start to want more?Speaking to Mike Donahue, former McDonalds Vice President, Peretti explores the history behind the idea of supersizing. 40 years ago, McDonalds hired David Wallerstein, a former cinema manager who had introduced the idea of selling larger popcorn servings in his Chicago cinema. Wallerstein realised that people would eat more but they did not like the idea of appearing gluttonous by going back for seconds. By increasing the portion sizes and the cost, he could sell more food. In 1972, he introduced the idea to McDonalds and their first large fries went on sale.