Sixty-three per cent of UK adults are now considered overweight or obese and many experts think that we are eating far too many of the wrong sort of carbohydrate.

Dr Xand van Tulleken is keen to discover whether they really are a killer, as claimed by many.

He tries a simple test with volunteers to determine how well they tolerate starchy carbs like rice, pasta and bread.

The cracker test and how our bodies cope with carbs is investigated in The Truth About Carbs on 6 June at 20:00 BST on BBC One and after on the BBC iPlayer.