How to Compare Packaged Functional Foods: A Checklist With No Rankings
A step-by-step checklist for comparing two packaged foods by serving size, percent Daily Value, ingredients, allergens and claims, with no brands and no rankings, plus what research says about label use.
Content last updated . This page has not been medically reviewed.
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What this page is, and is not
This is a checklist for comparing two packaged foods, such as two yogurts, two cereals or two juices. It names no products and ranks nothing. There is no universal winner: the best match depends on the person, such as blood pressure, kidney disease, diabetes, allergies or a child's age. Those are questions for a clinician or registered dietitian. It describes U.S. rules unless noted.
The checklist
| Step | What to do | What the sources say |
|---|---|---|
| Compare per the same amount. If one label uses a bigger serving, the numbers are not comparable. | FDA: "remember to make sure the serving size is the same" when using %DV to compare products. [1] The NHS adds that a manufacturer's idea of a portion may differ from yours. [2] |
| Look for lower %DV in saturated fat, sodium and added sugars, and higher %DV in fiber, vitamin D, calcium, iron and potassium. | 5% DV or less is low and 20% DV or more is high. [1] |
| Check the added sugars line. | Added sugars do not include sugars naturally in milk, fruits and vegetables. [3] |
| Check what comes first and what you need to avoid. | In whole-grain products, the Dietary Guidelines say the whole grain should be first, or second after water. [4] |
| Look in parentheses and in a "Contains" statement. | FDA names nine major allergens, including sesame since 2023. [5] |
| Nutrient amount, health claim or structure/function? | FDA defines these three categories. [6] |
| "Natural", "organic", "healthy", "probiotic" each need a different check (below). | See the sections that follow. |
Words that need a second look
- "Healthy". An FDA final rule announced December 19, 2024 updated this voluntary claim. A food must contain an amount from at least one food group and meet limits for added sugars, saturated fat and sodium. [7]
- "Natural". FDA has not engaged in rulemaking to establish a formal definition. Its longstanding policy is that nothing artificial or synthetic has been added that would not normally be expected in the food, and it did not address production methods such as pesticide use. [8] This page is dated October 2018; we did not read a later policy.
- "Organic". USDA describes four organic labeling categories: "100 percent organic", "organic" (at least 95 percent organic ingredients), "made with organic" (at least 70 percent) and a specific-ingredient listing. [9] Whether organic foods are healthier is not addressed in the sources we read.
- "Probiotic" or "live cultures". See probiotic claims on food labels.
- "High fiber" or "whole grain". See fiber and whole grain claims.
- "Fortified". The food needs at least 10 percent more of the Daily Value than a named reference food. [10] See fortified foods.
Front-of-package labels
Some countries add summary symbols to the front of the pack. The NHS describes UK labels that show energy, fat, saturated fat, sugars and salt, sometimes with red, amber and green colors. [2] WHO lists front-of-pack labelling among its best-buy policies for reducing sodium. [11]
What does research say? A systematic review of 7 studies of mandatory front-of-package labeling in Chile, Colombia, Ecuador and Mexico found that octagonal warning labels were associated with greater awareness and less selection of products high in sugar, sodium or saturated fat, but it offered little insight into long-term health impacts. [12] A review of 14 studies in young adults found that "graded indicators" had the most support, color-coded and positive-logo labels were close behind, and warning labels were mixed. [13] A review of 24 studies found that front-of-pack labels showed greater promise than the Nutrition Facts panel in reducing the bias health claims create. [14] These are behavior studies, not trials of disease outcomes.
Does label reading change what people eat?
| Question | What the source found | Strength of evidence |
|---|---|---|
| Is reading the Nutrition Facts label linked to healthier diets? | A systematic review of 26 studies found an association, with inconsistent results across studies. [15] | Promising but limited; mostly cross-sectional |
| Is using ingredient lists or serving-size information linked to diet? | The same review found insufficient research. [15] | Insufficient evidence |
| Do nutrition claims change choices? | A review of 11 studies found claims about fat, sugar and energy can make foods seem healthier and may lead some people to eat more. [16] | Mixed |
| Are label-reading habits linked to measured disease outcomes? | Proper evidence not found. Our PubMed searches for reviews of nutrition label use and diet returned studies of intake and choices, not disease outcomes. | Insufficient evidence |
What you can safely do
Compare per the same serving, favor lower added sugar and sodium within your own limits, keep allergens in view, and treat front-of-pack claims as a prompt to read the back. For health conditions, ask a pharmacist, clinician or dietitian. If someone has trouble breathing or swelling of the face or throat after eating, call 911.
Related pages
Reading food labels · Added sugars, sodium and saturated fat on labels · Claim checks · Evaluating safety claims
Frequently asked questions
Can I compare two foods with different serving sizes?
Only after matching the amounts. FDA says to make sure the serving size is the same when using %DV to compare. [1]
Is the food with the most green on a UK traffic-light label the best?
No winner is implied. The NHS says to go for more greens and ambers and fewer reds if you want to make a healthier choice, and that any red means high in fat, saturated fat, salt or sugars. [2] Whether that suits you depends on your needs.
Does "natural" mean it has no additives?
Not by a formal definition. FDA has not engaged in rulemaking to define "natural". [8]
Do front-of-package labels improve health?
The reviews we read measured awareness and choices, not health outcomes. [12]
Where can I get advice for a specific condition?
Ask a clinician, pharmacist or registered dietitian. See also functional food safety.
References
- U.S. Food and Drug Administration, How to Understand and Use the Nutrition Facts Label. Page content current as of 03/05/2024. Read 2026-10-23.
- NHS (UK), How to read food labels. Page last reviewed 30 June 2026. Read 2026-10-23.
- U.S. Food and Drug Administration, Added Sugars on the Nutrition Facts Label. Page content current as of 03/04/2026. Read 2026-10-23.
- U.S. Department of Agriculture and U.S. Department of Health and Human Services, Dietary Guidelines for Americans, 2020-2025 (9th edition, PDF). Read 2026-10-23.
- U.S. Food and Drug Administration, Food Allergies. Read 2026-10-23.
- U.S. Food and Drug Administration, Label Claims for Conventional Foods and Dietary Supplements. Page content current as of 03/28/2024. Read 2026-10-23.
- U.S. Food and Drug Administration, Use of the "Healthy" Claim on Food Labeling. Read 2026-10-23.
- U.S. Food and Drug Administration, Use of the Term Natural on Food Labeling. Page content current as of 10/22/2018. Read 2026-10-23.
- USDA Agricultural Marketing Service, Labeling Organic Products. Read 2026-10-23.
- U.S. Food and Drug Administration, 21 CFR 101.54, Nutrient content claims for "good source," "high," "more," and "high potency": eCFR. Read 2026-10-23.
- World Health Organization, Sodium reduction (fact sheet). Read 2026-10-23.
- Moreno-Mattar O et al. Systematic review of impact of mandatory front-of-package nutrition labeling on behavioral and cognitive outcomes and inequalities. Rev Panam Salud Publica 2026. PMID 42516616 (abstract). Read 2026-10-23.
- Guo Z et al. Impact of Five Types of Front-of-Package Nutrition Labels on Consumer Behavior among Young Adults: A Systematic Review. Nutrients 2024. PMID 39275139 (abstract). Read 2026-10-23.
- Talati Z et al. Consumers' responses to health claims in the context of other on-pack nutrition information: a systematic review. Nutr Rev 2017. PMID 28371913 (abstract). Read 2026-10-23.
- Anastasiou K et al. The relationship between food label use and dietary intake in adults: A systematic review. Appetite 2019. PMID 31010704 (abstract). Read 2026-10-23.
- Systematic review of the impact of nutrition claims related to fat, sugar and energy content on food choices and energy intake. BMC Public Health 2019. PMID 31615458 (abstract). Read 2026-10-23.