Calorie labeling doesn't deter shoppers from purchasing high-calorie foods: JAMA

Massachusetts: In a longitudinal study of supermarkets, it was found that calorie labeling of prepared foods was associated with small to moderate decreases in calories purchased by the customers without evidence of substitution for packaged substitutes. The study article was published in the JAMA Internal Medicine.

A calorie is a unit to measure the energy a food provides to the body. Calorie consumption that is too low or too high will eventually lead to health problems. The number of calories in food tells us how much potential energy they contain. It is not only calories that are important, but also the substance from which the calories are taken.

The 2010 Affordable Care Act requires chain retail food establishments, including supermarkets, to post calorie information for prepared (i.e., ready-to-eat) foods. In India, the FSSAI (Food Safety and Standards Authority of India) is the authority that mandates the food labeling (nutritional value) norms. The number of calories listed on the label shows how many calories are present in one serving. Large evaluations in restaurants suggest small declines in purchases of prepared foods after labeling, but to the authors' knowledge, no studies have examined how this policy influences supermarket purchases.

Joshua Petimar, Harvard Medical School & Harvard Pilgrim Health Care Institute, Massachusetts, and colleagues conducted a study to estimate changes in calories purchased from prepared foods and potential packaged substitutes compared with control foods after calorie labeling of prepared foods in supermarkets.

Researchers analyzed data from 173 supermarkets from one chain. They compared sales 2 years before labeling implementation with sales 7 months after labeling implementation. Purchased items were classified as prepared foods, potential packaged substitutes for prepared foods, or all other (ie, control) foods. The primary outcome was mean weekly calories per transaction purchased from prepared foods, and the secondary outcome was mean weekly calories per transaction purchased from similarly packaged items (for substitution analyses). Analyses of prepared and packaged foods were stratified by food category (bakery, entrées and sides, or deli meats and cheeses).

Key findings of the study,

• calories purchased from prepared bakery items declined by 5.1% after labeling, and calories purchased from prepared deli items declined by 11.0% after labeling, adjusted for pre-labeling trends and changes in control foods; no changes were observed among prepared entrées and sides.

• Labelling was associated with decreased calories per transaction purchased from packaged bakery items, packaged entrées and sides, and packaged deli items.

The authors conclude that labels containing calorie information on prepared food items led to small to moderate decreases in calories purchased from the prepared bakery and deli items. Studies showed that calories purchased from similarly packaged items did not increase after labeling.

Reference:

Petimar J, Grummon AH, Zhang F, et al. Assessment of Calories Purchased After Calorie Labeling of Prepared Foods in a Large Supermarket Chain. JAMA Intern Med. Published online August 01, 2022. doi:10.1001/jamainternmed.2022.3065