Kids are the key to understanding obesity. But we need more of their genes...

We can unravel the role that bodyweight plays in disease, but we need a bigger, more diverse, sample of genetic material to do so

- Prof Giles Yeo

When I was a young postdoctoral researcher at Cambridge in 2002, a colleague took me to a fancy dinner at Peterhouse College, the oldest of Cambridge's colleges. It was a six-course affair, and, rather ridiculously, you had to change seats (and hence dinner companions) for each new course. During the first course, an older, bearded professor sitting opposite me asked, "So young man, what do you do?"

I told him I was working on the genetics of childhood obesity.

"Ha! Do you know what your problem is?” he replied. "You give fat people an excuse."

The disgust in his tone threw me, and as I mobilised all my diplomatic nous to gently push back, I was saved by a literal bell, signalling that we had to switch seats for course number two.