The easy way to describe epigenetics is to say it is about what switches our genes on and off. Circumstances in our life can cause genes to be silenced (switched off) or expressed (switched on). Some of the things that do this relate to what we eat, how much we sleep, where we live, and how much exercise we take. It has been suggested that there is an epigenetic switch for obesity. Interest in the future will be on what triggers the switch and how can it be turned off.