GDA = „Guideline Daily Amount“ 

These values are based on the CIAA’s (Confederation of the Food and Drink
Industries of the EU) recommendations. They refer to the recommended daily
intake of a middle-aged woman with an average level of physical activity, and
can therefore vary for each person according to their sex, age and physical
activity level.

Example:

This means that 300 kcal/62 kcal equal 20%/3% of the total number of kcal
required each day by a middle-aged woman whose level of physical activity
is average.

Below are the basic data used for calculating GDAs: 

  Source: http://gda.ciaa.eu/asp/welcome.asp