being purchased means more revenues for those selling food. i ll talk more about that later but the just to feed the excess weight of america is probably about $50 billion a year. childhood obesity is also epidemic and childhood obesity has tripled in just a generation. we know that our genes haven t changed this fast. we know that our preferences have changed that fast. we are hardwired to like sweet and salty food. what has changed is our environment and if we are to make a change in the obesity epidemic we re going to have to change the environment again in order to gain control. obesity affects virtually every body system from the lungs, cardiovascular disease, fatty liver, stroke, cat and various lung cancers so the health implications of obesity are major and this really represents a dramatic change in the nature of society. as depicted in the next slide. [laughter] now, thinking about how we can address this epidemic we think about how we address any public healt