The study examined two components of consumer understanding of food energy information: understanding the concept of energy and its quantity. Using this new framework, we investigated whether activity-equivalent labels facilitated interpretations of food energy compared with calorie labels and whether an image format would strengthen this facilitative effect compared with text.

We assessed the effect of energy representation and format in a 2 (activity v. calories)×2 (image v. text) between-subjects design. Conceptual understanding of energy was measured in terms of level of understanding and personal engagement. Quantitative understanding was measured in terms of participants’ estimations of a food’s contribution to their recommended daily intake and perceptions of energy values as precise or single-bound interval estimates.

The experiment was conducted online through Qualtrics.

Eight hundred and twelve participants (55 % female, age range 18–74 years) were recruited through a national survey panel in the UK.

Participants were twice more likely to have a stronger conceptual understanding of energy and four times more likely to personally engage with activity labels v. calorie labels. Participants did not differ across labels in their estimations of energy quantities; however, they inferred quantities to mean exactly the stated number of calories, but at least the stated activity duration. There were no added benefits in presenting an image over the text format.

Activity labels can facilitate conceptual understanding of energy, but may be subject to quantitative misinterpretations. Nutrition communication should consider what people infer from quantities represented on labels.