Why are we so fat? We have not become greedier as a race. We are not, contrary to popular wisdom, less active – a 12-year study, which began in 2000 at Plymouth hospital, measured children’s physical activity and found it the same as 50 years ago. But something has changed: and that something is very simple. It’s the food we eat. More specifically, the sheer amount of sugar in that food, sugar we’re often unaware of.