The donut as a symbol consists of two circles. 

The outer one describes on nine fields the planetary boundaries that humanity must not exceed, for example ocean acidification, biodiversity or global warming. The inner circle defines the social needs that every human being has for a successful life: clean water, education, social and political participation. Raworth calls the area in between the „sweet spot“ (anyone who has ever eaten a donut knows: they are usually sweet). In the sweet spot, each person can flourish in a safe and equitable space without living at the expense of others.

Donut Theorie Diagramm