Self-tracking technologies have created new conditions for self-management and self-control. Research has shown how these technologies and their design are shaped by ideological assumptions and norms, particularly in their interactions with users. However, less attention has been given to the interplay between interface design, user interaction, and meaning making, especially in the context of food and health. This article uses multimodal critical discourse analysis to explore how the interface design of a commercial calorie-tracking app, along with the actions it enables, constructs and reinforces health and healthy eating as scientific practices. It also highlights how healthy eating is framed as something the user must choose, control, adapt, take responsibility for, and improve. Through interface design choices, commercial actors can sustain and reproduce ideas and ideologies linked to nutritionism, wellness and neoliberalism, while simultaneously benefiting from them.