This article considers the role of consumers in the regulation of nanotechnology. The principal regulatory response to nanotechnology to date has been to require the disclosure of information. One such mechanism currently under negotiation in the food sector is the mandatory labelling of nanomaterial ingredients, commonly justified on the ground that consumers have the right to know what they eat. Not only does this provide a vehicle for free market choice but it also offers one of the few routes to citizen engagement in the policy debate. The potential benefits of nano labelling are substantial. As this article seeks to show, however, the demands placed on nano labelling may be difficult to meet because of a range of limiting factors. By highlighting an expectation-capacity gap, this article points to the need for developing a richer choice environment and for scrutinising difficulties not fully addressed in the policy discourse.