Nestle, the world's biggest packaged food group, is doubling spending on its restructuring this year to up to 1 billion Swiss francs ($1 billion) to cope with its weakest sales growth in more than two decades.

Europe's largest company by market value is under pressure to improve returns from activist investor Daniel Loeb, whose Third Point hedge fund revealed a $3.5 billion stake in June.

Organic sales rose 3.1 percent in the third quarter, up from 2.4 percent in the second and the performance was helped by improved trading in Europe and Asia. The sources from the company cautioned that Europe and Asia might not be able to repeat the good performance over the final three months.

Yet its overall forecast for restructuring costs of 2.5 billion francs between 2016 and 2020 remained unchanged.