Consumer Understanding of Calorie Amounts and Serving Size: Implications for Nutritional Labelling

Objective: Increased consumption of sugar-sweetened beverages has contributed to rising obesity levels. Under Canadian law, calories for prepackaged foods and beverages are presented by serving size; however, serving sizes differ across products and even for the same product in different containers. This study examined consumer understanding of calorie amounts for government nutrition labels and industry labelling schemes. Methods: A national sample of 687 Canadian adults completed an online survey. Participants were randomized to view images of Coke (R) bottles that displayed different serving sizes and calorie amounts. Participants viewed either the regulated nutrition information on the back of containers, or the voluntary calorie symbols displayed on the front of Coke (R) products. Participants were asked to determine how many calories the bottle contained. Results: Across all conditions, 54.2% of participants correctly identified the number of calories in the beverage. Participants who viewed government-mandated nutrition information were more likely to answer correctly (59.0%) than those who saw industry labelling (49.1%) (OR=5.3, 95% CI: 2.6-10.6). Only 11.8% who viewed the Coke (R) bottle with calorie amounts per serving correctly identified the calorie amount, compared to 91.8% who saw calorie amounts per container, regardless of whether information was presented in the Nutrition Facts Table or the front-of-pack symbol (OR=242.9, 95% CI: 112.1-526.2). Conclusions: Few individuals can use nutrition labels to correctly identify calorie content when presented per serving or using industry labelling schemes. The findings highlight the importance of revising labelling standards and indicate that industry labelling initiatives warrant greater scrutiny.