 Rival supermarkets are using different labelling methods |
The labels show percentages of guideline daily amounts (GDA) of sugar, salt, fat and calories in each serving.
Other firms use red, amber and green labels - where green is good and red warns not to consume too much - approved by the Food Standards Agency.
But the 21 firms and retailers using the GDA system say people will not buy products with red labels on them.
The GDA campaign - supported by a coalition of the UK's biggest food and drink manufacturers as well as supermarkets Tesco, Somerfield and Morrison - begins on Monday with TV and print adverts.
Members of the GDA group say consumers will find the percentages of GDAs easier to understand than the FSA's "traffic light" system.
Source: BBC News