eMark colours are designed to tell you how quickly the energy in a food or drink is converted to glucose and released into the bloodstream, ready for the body to use as fuel. This is called the Relative Glycaemic Impact of the food.
Energy release or relative glycaemic impact is defined in three categories, represented by the following eMark colours:
- blue for foods that release energy slowly, giving you long-lasting or sustained energy
- green for foods that will sustain you for a medium length of time
- yellow for foods that will give you a fast burst of energy but won’t sustain you for very long
Blue foods are mainly composed of fat, protein, complex carbohydrates, and/or fibre, which are slowly broken down in the body and provide long-lasting energy.
Yellow foods are high in sugar and/or simple carbohydrates. They are quickly digested and converted to glucose, making energy rapidly available – but the energy will also be used very quickly.
Green foods fall in between these two extremes, and signify a medium energy release.
Energy release values are determined using scientific tests which measure the rate at which energy is released from foods. Tests are still being established for some food groups, so at this stage any products which cannot be tested for their energy release rate will be coloured grey.