Magic Porridge Before bed, mix 1 sachet of plain OatsoSimple or similar with a fat free yoghurt - I use Mullerlight and change the flavours. Leave it in the fridge overnight - the porridge doubles in size! You can mix this with fresh fruits or just eat it as it is. This is a healthy extra B choice on Slimming World, great for a summer day when you don't want hot porridge!