A trip to the grocery store seems to require more reading than ever these days: nutrition Facts panels on the back; low-sodium, low-fat, fat-free, dairy-free, no added sugar and more on the front. But even as food producers adapt the “more is more” attitude toward cluttered packaging, little evidence exists to show if consumers improve their eating habits because of food labels.
Summary: An analysis of studies that looked at how labeling on food packaging, point-of-sale materials and restaurant menus prompted consumers to eat fewer calories and fat; reduce their choice of other unhealthy food option; and eat more vegetables.
The study also found that labels prompted food producers to lower the amounts of trans fat and sodium in their offerings.
The study: Researchers sought to determine if the labels changed consumer behavior, prompted industry transformations or affected diet-related health measures.
The findings: Because of labeling, consumers chose food with 6.6 fewer calories and 10.6 percent less total fat. They also selected 13 percent fewer other unhealthy food options such as sugar-sweetened beverages, alcoholic beverages, non-alcoholic caloric beverages, french fries, potatoes, white bread, and foods high in saturated fat, trans fat, added sugars or sodium.
Labels did not seem to alter consumption of carbohydrates, protein, saturated fat, fruits or whole grains.
Alternately, they did not increase consumption of healthy options such as salads, soups, low-fat dairy, lean meat, fish and seafood, and more. However, consumers opted to eat 13.5 percent more vegetables because of food labels.
In addition, labeling has inspired food companies to reduce the amount of sodium by 8.9 percent and trans fat by 64.3 percent in their products.
Study conclusions: Food labels are an effective way to reduce consumers’ consumption of calories and fat, as well as increase their intake of vegetables.
Labeling also prompted manufacturers to reduce the amounts of sodium and trans fat in their products, but manufacturers did not significantly change the amount of calories, saturated fats, dietary fiber or the other healthy and unhealthy food options mentioned above.
Why the research is interesting: A 2017 study, published in the Journal of the American Medical Association, found an association between diet and cardiometabolic deaths. Ten dietary factors combined were associated with 45.4 percent of all cardiometabolic deaths in 2012. Of those, 9.5 percent were related to high consumption of sodium; 8.5 percent to low consumption of nuts and seeds; 8.2 percent to high consumption of processed meats; 7.8 percent to low consumption of seafood or omega-3s; and 7.6 percent to low consumption of vegetables.
Evidence regarding the effectiveness of food labels has been sparse, and some meta-analyses have reported inconsistent findings. This work analyzed more studies, a larger variety of labeling and industry as well as consumer responses. Consequently, this study is able to confirm the effects of labeling on specific dietary options.
However, this study calls for more investigation of other dietary targets or to determine if the labels target certain dietary outcomes. In addition, the study’s authors suggest researching the relationship between food labels and the risk of disease such as cardiometabolic syndrome.
As more countries require the labeling of added sugars in foods, other researchers will have to evaluate if the industry reduces the amount of sugar it adds to food.
Points to consider: The data in this study can easily be applied to the general population because many of the studies were “natural experiments,” not randomized studies. Newer studies regarding this topic were not included in this meta-analysis, as the researchers stopped looking for studies in 2015.
A more recent study—“A systematic review, and meta-analyses, of the impact of health-related claims on dietary choices,” published in the International Journal of Behavioral Nutrition and Physical Activity in 2017—looked at the results of 31 papers that measured whether consumers were more likely to choose a product with a health claim on the label. Twenty of those studies found that health claims increase the purchasing and/or consumption of such products. The authors of this study caution that more research in real-world settings is needed.
Current food label standards: The Food and Drug Administration’s Nutrition Facts panel requires manufacturers to include reasonable serving sizes and, on a per-serving basis, the product’s amount of calories; total fat, saturated fat and trans fat; cholesterol; sodium; total carbohydrate, dietary fiber; total sugars and added sugars; and protein.
The FDA also specifies when foods can make claims regarding sodium, fat, cholesterol and more.
How it was done: Researchers looked at 60 studies that included a total of 2 million observations in 11 countries to determine if food labels change consumer behavior. Labels included the Nutrition Facts panel, calorie information on menus, graphics such as “traffic lights”, logos and nutrition or health claims.
The study did not include labels that included only ingredient information, allergen or safety warnings or marketing pieces.
- Siyi Shangguan, M.D., Peking University, Beijing, China; master’s of public health, Harvard University, Boston, Massachusetts; associated with Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, and Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
- Ashkan Afshin, M.D., Tehran University of Medical Sciences; doctor of science, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts; associated with Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, and Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington.
- Masha Shulkin, bachelor’s of science from University of Michigan; associated with Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, University of Michigan Medical School, Ann Arbor, Michigan, and; T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts.
- Dariush Mozaffarian, M.D., Columbia University, New York, New York; doctor of public health, Harvard University, Boston, Massachusetts; dean of the Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts.
- Also, Wenjie Ma, doctor of science; Daniel Marsden, B.S.; Jessica Smith, Ph.D.; Michael Saheb-Kashaf, master’s of public health; Peilin Shi, Ph.D.; Renata Micha, Ph.D.; and Fumiaki Imamura, Ph.D.
Published: "A meta-analysis of food labeling effects on consumer diet behaviors and industry practices," American Journal of Preventative Medicine, February 2019 (published online Dec. 17, 2018)