Filmed over three years at Columbia University Medical Center in New York, Naturally Obsessed follows a trio of students as they search for the trigger for human appetite.

This could make for a dry academic documentary but Richard and Carole Rifkind take a human interest in the students, struggling towards their PhDs under their mentor Dr Lawrence Shapiro. There is much at stake but also many laughs along the way in a documentary hailed by The Washington Post as a "funny, lively, thoroughly absorbing and deeply affecting". The students must master x-ray crystallography in an attempt to map the structure of the protein AMPK which controls the burning and storage of fat. Knowing how AMPK works could enable scientists to regulate its activity, leading to treatments for obesity and diabetes.

For one student, the course ends in success and viewers will see the AMPK structure revealed. For the other two, there is the crushing realisation that, after all their efforts, the real prize has slipped through their fingers.