Ideally you need something edible that contains high and low gycemic Index sources. The answer is the ingredients pictured. Oats for slow release of energy, peanut butter for medium and the mars bars for fast release. To make them simply put all the ingredients into a microwaveable bowl and blitz until it is a melted gooey mess and stir together. Then place into a square Tupperware bowl and let it cool down in the fridge overnight. Cut into blocks and wrap in cling film. Sorted.