The second in a new Horizon trilogy of documentaries on the nation's weight and health.
As the search goes on to find drugs with the power to cut down appetite by resetting control mechanisms in the brain, new research uncovers the powerful food ingredients that could win the slimming war.
See today's choices.
(Digital widescreen)
BBC video and book: Fighting Fat, Fighting Fit video, £10.99, and book including health advice and recipes, £5.99