I have seen men lose kilos just from doing this alone! Butter and marg are more than 80% fat. One slice of bread spread generously has the same kilojoules as 2 naked slices – it’s not rocket science working out which will fill you up more!
A good alternative is Philadelphia extra light cream cheese (5% fat and not to be confused with “light” cream cheese at around 15% fat). Otherwise try hummus, a thin spread of mashed avocado, mustard or relish. You will save lots of kilojules and the chances are you will soon not miss the more traditional spreads!