We manipulated the presence and spatial location of calorie labels on menus while tracking eye movements. A novel "lab-in-the-field" experimental design allowed eye movements to be recorded while participants chose lunch from a menu, unaware that their choice was part of a study. Participants exposed to calorie information ordered 93 fewer calories (11%) relative to a control group who saw no calorie labels. The difference in number of calories consumed was greater still. The impact was strongest when calorie information was displayed just to the right of the price, in an equivalent font. The effects were mediated by knowledge of the amount of calories in the meal, implying that calorie posting led to more informed decision-making. There was no impact on enjoyment of the meal. The eye-tracking data suggested that the spatial arrangement altered individuals' search strategies while viewing the menu. This research suggests that the spatial location of calories on menus may be an important consideration when designing calorie posting legislation and policy. Copyright © 2019 Elsevier Ltd. All rights reserved.