This research addresses the spread of fake news on social networks and the growing concern about food. The objective is to analyze the role of leading Spanish nutritionists as fact-checkers on Instagram. Using the web scraping technique, 2,100 posts were extracted, between January 1 and June 30, 2019. They were then classified using an unsupervised semantic analysis and, later, the comments related to falsehoods (3.9%) were selected. The results show that these food influencers performing a fact-checking role on Instagram is a low profile one, they do not take advantage of the audiovisual features of the medium. Nonetheless, such a performance allows them to enhance a role independent from the food industry and, at the same time, to build community with their followers.