Food Label Evidence

Article

Can people actually read a nutrition label?

Whether a label changes what people buy is a different question from whether people understand what it says. A large body of research asks the second question directly, and the answer is: often not very well, and not evenly across the population.

Updated 4 min read 19 citations

Nutrition Facts panel showing 94 percent of the daily value for saturated fat
Percentage daily values only make sense once the serving size at the top is checked. B137 · CC0 · Wikimedia Commons

The comprehension gap is old news, and still true

A 2005 systematic review of consumer understanding and use of nutrition labelling already documented the core problem two decades ago: presence of a label is not the same as comprehension of it, and comprehension is not the same as behaviour change [3]. That three-way gap — presence, comprehension, use — is the frame the rest of this field still works within, and it is the frame most "does labelling work" coverage collapses into one question.

A 2017 scoping review on health literacy, literacy, numeracy and nutrition label understanding sharpened this further: general literacy and health literacy predict label comprehension, but numeracy — the ability to actually work with percentages and per-100g comparisons — is the stronger and more specific predictor [15]. A label full of numbers is, unsurprisingly, a numeracy task before it is a nutrition task.

Format changes what people can extract, not just what they notice

Label formatWhat comprehension research shows
Plain numeric panel (text only)Lowest comprehension for at-a-glance judgements; requires numeracy and time
Traffic-light (red/amber/green)Faster, more accurate at-a-glance categorisation in comparative trials
Single-letter score (e.g. Nutri-Score)Fast categorisation; can misfire on the specific edge cases the underlying algorithm handles per-100g
Warning labels (e.g. octagon/stop-sign)High immediate recognition; effects on purchase intention studied separately from comprehension

A randomised trial investigating the one-week effect of traffic-light nutrition labelling on diet selection among Japanese university students is a useful data point here specifically because it isolates format rather than just measuring "labelling versus none [4]." A separate Brazilian randomised experiment comparing two front-of-package label designs found that design choice measurably changes how quickly and accurately people extract the intended information — not just whether they glance at the label at all [7].

Numeracy and time pressure matter more than motivation

A study of time preference and nutrition label use, using data from China, found that how much weight people give to future health outcomes versus immediate gratification predicts whether they engage with a label at all — a reminder that comprehension research keeps finding that motivation to read carefully is not the bottleneck for a meaningful share of shoppers [18]. Time pressure at the shelf compounds this: a label that requires arithmetic to interpret is a label most people will not do arithmetic for, however literate they are in principle.

This is the empirical case for simplified, colour- or letter-coded systems over the plain numeric panel: they move the interpretive work from the shopper's numeracy to the label designer's algorithm. It is also the empirical case against assuming a redesigned label alone fixes anything — an Italian randomised controlled trial testing different front-of-pack nutrition label formats, and a French randomised trial testing the effect of displaying Nutri-Score in food advertising specifically, both found format-dependent differences in comprehension and stated purchase intention, not uniform gains from any label existing [5][10].

Comprehension does not automatically produce behaviour change

A 2018 meta-analysis on the effect of nutrition labels on dietary quality among college students, and a review on the influence of front-of-package nutrition labelling on consumer behaviour and product reformulation, both point to the same asymmetry covered on our Nutri-Score page: comprehension effects are larger and more consistent than purchasing effects [2][14]. People can correctly interpret a label and still buy the less healthy option for reasons the label was never going to address — price, taste preference, habit, what is actually in the cupboard. A French randomised controlled trial on the impact of the Nutri-Score front-of-pack label found purchasing-intention effects that were real but consistently smaller than the comprehension gains reported in the same literature [8].

What this means practically

Comprehension research supports three narrow, defensible conclusions rather than one sweeping one. First, format matters independently of content — the same information presented as a letter grade, a colour code, or a numeric panel is not equally usable by the average shopper. Second, numeracy is the more specific bottleneck compared with general literacy, so simplified formats disproportionately help lower-numeracy shoppers rather than everyone equally. Third, and most important for policy debates: solving comprehension is a necessary but not sufficient step toward changing what ends up in the trolley.

Common questions

Do most people actually understand nutrition labels?
Comprehension is inconsistent and correlates more with numeracy than with general education. A classic systematic review documented this gap, and later scoping review work confirmed numeracy as the sharper predictor.
Is a traffic-light label easier to understand than a numeric panel?
Comparative research, including a Japanese randomised trial, supports faster and more accurate at-a-glance interpretation for colour-coded formats over plain numeric panels.
If I understand a label, will I actually buy the healthier option?
Not necessarily. Comprehension and purchasing behaviour are measured separately in this literature, and the comprehension effect is consistently the larger of the two.
Does label design affect different label formats differently across countries?
Yes — Brazilian and Italian randomised trials of different front-of-pack designs both found comprehension differences tied to specific format choices, not a single universal effect of "having a label."
Close view of a printed ingredient list on food packaging
Chenspec · CC BY-SA 4.0 · Wikimedia Commons
The evidence behind this page A stacked bar showing the composition of the 19 publications cited on this page by study type. 31042meta-analysis (3)randomised trial (10)review (4)other (2)
19 publications, 2005–2024. That is a mix with both trials and syntheses in it, which is the position from which a claim about cause is reasonable. Source: this page’s own citation list, below.

References

Every citation below links to the original peer-reviewed record on PubMed or via DOI. Nothing here is a substitute for medical advice.

  1. Effect of front-of-package nutrition labeling on food purchases: a systematic review An R, Shi Y, Shen J, et al. · Public health · 2021 · Systematic review DOIPubMed 33517247
  2. Effect of nutrition labels on dietary quality among college students: a systematic review and meta-analysis Christoph MJ, An R · Nutrition reviews · 2018 · Meta-analysis DOIPubMed 29373747
  3. Consumer understanding and use of nutrition labelling: a systematic review Cowburn G, Stockley L · Public health nutrition · 2005 · Systematic review DOIPubMed 15705241
  4. Investigation of the 1-week effect of traffic light nutrition labeling on diet selection among Japanese university students: a randomized controlled trial Wakui N, Matsuoka R, Ichikawa K, et al. · BMC public health · 2024 · Randomised controlled trial DOIPubMed 38317163Full text
  5. A randomized controlled trial to test the effects of displaying the Nutri-Score in food advertising on consumer perceptions and intentions to purchase and consume Courbet D, Jacquemier L, Hercberg S, et al. · The international journal of behavioral nutrition and physical activity · 2024 · Randomised controlled trial DOIPubMed 38622707Full text
  6. Effectiveness of a Sodium-Reduction Smartphone App and Reduced-Sodium Salt to Lower Sodium Intake in Adults With Hypertension: Findings From the Salt Alternatives Randomized Controlled Trial Eyles H, Grey J, Jiang Y, et al. · JMIR mHealth and uHealth · 2023 · Randomised controlled trial DOIPubMed 36892914Full text
  7. A comparative assessment of two different front-of-package nutrition label designs: A randomized experiment in Brazil Khandpur N, Amaral Mais L, Bortoletto Martins AP · PloS one · 2022 · Randomised controlled trial DOIPubMed 35385504Full text
  8. The impact of the Nutri-Score front-of-pack nutrition label on purchasing intentions of unprocessed and processed foods: post-hoc analyses from three randomized controlled trials Egnell M, Galan P, Fialon M, et al. · The international journal of behavioral nutrition and physical activity · 2021 · Randomised controlled trial DOIPubMed 33731145Full text
  9. Nutri-Score: The Most Efficient Front-of-Pack Nutrition Label to Inform Portuguese Consumers on the Nutritional Quality of Foods and Help Them Identify Healthier Options in Purchasing Situations Goiana-da-Silva F, Cruz-E-Silva D, Nobre-da-Costa C, et al. · Nutrients · 2021 · Randomised controlled trial DOIPubMed 34959887Full text
  10. Effectiveness of Different Front-of-Pack Nutrition Labels among Italian Consumers: Results from an Online Randomized Controlled Trial Fialon M, Egnell M, Talati Z, et al. · Nutrients · 2020 · Randomised controlled trial DOIPubMed 32752021Full text
  11. Do nutrition labels influence healthier food choices? Analysis of label viewing behaviour and subsequent food purchases in a labelling intervention trial Ni Mhurchu C, Eyles H, Jiang Y, et al. · Appetite · 2018 · Randomised controlled trial DOIPubMed 29191745
  12. Impact of Different Front-of-Pack Nutrition Labels on Consumer Purchasing Intentions: A Randomized Controlled Trial Ducrot P, Julia C, Méjean C, et al. · American journal of preventive medicine · 2016 · Randomised controlled trial DOIPubMed 26699246
  13. Nutrition labels decrease energy intake in adults consuming lunch in the laboratory Temple JL, Johnson K, Recupero K, et al. · Journal of the American Dietetic Association · 2010 · Randomised controlled trial DOIPubMed 20630169
  14. The Influence of Front-of-Package Nutrition Labeling on Consumer Behavior and Product Reformulation Roberto CA, Ng SW, Ganderats-Fuentes M, et al. · Annual review of nutrition · 2021 · Review DOIPubMed 34339293
  15. Health literacy, literacy, numeracy and nutrition label understanding and use: a scoping review of the literature Malloy-Weir L, Cooper M · Journal of human nutrition and dietetics : the official journal of the British Dietetic Association · 2017 · Review DOIPubMed 27731526
  16. Correlates of nutrition label use among college students and young adults: a review Christoph MJ, An R, Ellison B · Public health nutrition · 2016 · Review DOIPubMed 26549218Full text
  17. Food and the consumer: could labelling be the answer? Kerr MA, McCann MT, Livingstone MB · The Proceedings of the Nutrition Society · 2015 · Review DOIPubMed 25998678
  18. Time preference and nutrition label use: Evidence from China Guan L, Huang Z, Jin S · Economics and human biology · 2022 · Journal article DOIPubMed 36116174
  19. The understanding, attitude and use of nutrition label among consumers (China) Song J, Huang J, Chen Y, et al. · Nutricion hospitalaria · 2015 · Journal article DOIPubMed 26040385