Large companies in the food industry have significant economic power, and this translates readily into political influence. There is currently a risk that the political influence of the food industry results in public health policies that do not adequately balance public and commercial interests. There is thus a need to increase the transparency and accountability of governments and the food industry in relation to public health policies. Here we present a framework for categorising the corporate political activity of the food industry with respect to public health, and propose an approach to systematically identify and monitor it. The proposed framework includes six strategies used by the food industry to influence public health policies and outcomes: information and messaging; financial incentive; constituency building; legal strategies; policy substitution; opposition fragmentation and destabilisation. We propose that the corporate political activity of the food industry could be identified and monitored through publicly available data sourced from the industry itself, governments, the media and other sources. Steps for country-level monitoring include identification of key food industry actors and related sources of information, followed by systematic data collection and analysis of relevant documents, using the proposed framework as a basis for classification of results. We present initial results from implementing the approach in Australia and Fiji. This is supplemented by results from interviews with key informants in each country that aimed to assess the feasibility and value of the approach.