We examine the relationship between BMI and food purchase behavior using a unique dataset that links individual-level food purchases to health data. We find that individuals with higher BMI are significantly more sensitive to price changes in vice categories but do not show similar sensitivity in comparable nonvice categories. We rely on past literature that defines and identifies vice categories as those that are tempting and purchased impulsively. We explore the effectiveness of a 10% price increase on vice food categories, a hypothetical policy similar in spirit to a fat tax or sugar tax. We predict that such a tax would substantially reduce consumption of these foods, and would be particularly effective in reducing consumption by individuals with higher BMI.

This paper provides a commentary on Lacy-Nichols and Williams\' analysis of the emerging tactics of the ultraprocessed food transnational corporations (TNCs). Our paper provides an overview of the growth in power and influence of TNCs in the past three decades and considers how this change impacts on health and health equity. We examine how wealth inequities have increased dramatically and how many of the health harms are externalised to governments or individuals. We argue that human interests and corporate interests differ. The article concludes with a consideration of alternative ways of organising an economy that are more human centred and health promoting. We suggest five changes are required: improved measurement of economic outputs beyond gross domestic product (GDP); improved regulation of finance and TNCs; development of localised economic models including cooperatives; reversal of privatisations; making the reduction of economic inequalities a goal of financial policy. We consider the barriers to these changes happening.