To measure incidence of conflicts of interest (COI) with food and pharmaceutical industry actors on the advisory committee for the 2020–2025 US Dietary Guidelines for Americans (DGA) and assess the adequacy of current mechanisms to disclose and manage COI among the committee’s members.

We compiled longitudinal data from archival sources on connections between members of the DGA’s advisory committee and actors. We hypothesised that these committee members, who oversee the science for the most influential dietary policy in the USA, might have significant COI that would be relevant to their decision making. Disclosure of COI on this committee was recommended in 2017 by the National Academies of Sciences in order to increase transparency and manage bias, but public disclosure of the committee’s COI does not appear to have taken place.

The committee was composed of twenty experts.

None.

Our analysis found that 95 % of the committee members had COI with the food and/or pharmaceutical industries and that particular actors, including Kellogg, Abbott, Kraft, Mead Johnson, General Mills, Dannon and the International Life Sciences, had connections with multiple members. Research funding and membership of an advisory/executive board jointly accounted for more than 60 % of the total number of COI documented.

Trustworthy dietary guidelines result from a transparent, objective and science-based, process. Our analysis has shown that the significant and widespread COI on the committee prevent the DGA from achieving the recommended standard for transparency without mechanisms in place to make this information publicly available.