When my morbid fascination with eating and obesity started - seven years ago - nearly 400 million people were obese. That really is a huge amount of people. And by 2015 it will apparently be more like 700 million.

Many people still think obesity results from a weak character, but to suggest that 10% of the world spontaneously lost its balls in the last few years? Well it's starting to sound like a pretty weak argument.

As a psychologist specializing in appetite and obesity I've been devouring all the weight-related research I can digest for an extra-large portion of my life - and I think it's about time to start offloading some of the extra pounds.

Can you inherit obesity if your family has ‘fat genes'? Why is it easier to binge on some foods than others? Why do people eat more popcorn when it's in a super-size packet? Does losing weight really make you happy? Why do we eat when we're not actually hungry? Why is it so hard to stick to a diet? What effect does our ethnic background have on how we eat? If a child is obese, are indulgent or neglectful parents to blame? Can we train ourselves to eat better? Are obese people biologically different from everybody else? And why do only some of us get fat, while others find it exasperatingly easy to stay skinny as rakes?