The Centre for Science in the Public Interest (CSPI) is an independent health advocacy organization with offices in Ottawa and Washington. CSPI's Ottawa advocacy efforts are supported by more than 100,000 subscribers to the Canadian edition of its Nutrition Action Healthletter, which was launched in 1996.

For more than a decade, CSPI has been an important force in stimulating changes to government policies and industry practices to improve the nutritional quality of the Canadian food supply and, most importantly, the health of Canadians. CSPI led a coalition of health and citizens groups in a six-year public advocacy campaign for mandatory nutrition labeling on pre-packaged foods. Regulations requiring such labels were promulgated in December 2002.

Since then, CSPI has urged governments and food companies to improve nutrition standards for schools, reduce the amount of salt and trans fat added to processed foods, limit advertising targeting children, improve nutrition labelling on food packages and restaurant menus, ensure that natural health products are safe and effective, ensure government dietary advice and food tax policy reflect sound health science, not commercially-motivated lobbying. CSPI helped formulate advice to the federal Minister of Health through its membership in both the federal Trans Fat Task Force (2004-2006), and the Sodium Working Group (2008-present).

CSPI does not accept industry or government funding and Nutrition Action does not carry advertisements.