I keep hearing about foods having 'empty calories'. What are they and what's so bad about them?
Aaron Piggott, by email

Nutritionist Dr Sarah Schenker replies: Empty calories is the term used for foods that provide energy in the form of calories but contain very little other nutrients, particularly vitamins and minerals. Sugar and sugary foods and drinks tend to fall into this category. For instance, a handful of jelly beans will give you instant energy from the sugar, but they contain no other nutrients, whereas a kiwi fruit gives you the same amount of energy (from natural fruit sugars) but also provides vitamin C, folate, potassisum and fibre.