Serving Size Traps on Nutrition Labels
How FDA serving size rules work, why package serving sizes changed in recent years, and how added sugars are declared separately from total sugars.
This article is informational only and is not medical advice. It explains how to read a US Nutrition Facts label, not what you personally should eat.
One of the easiest mistakes when reading a nutrition label is assuming the listed serving size matches what you'd actually eat in one sitting. The FDA has specific, legally defined rules for how serving sizes are set, and understanding them helps explain why two similar-looking products can have very different numbers.
Serving sizes are based on what people actually eat, not what they should eat
According to the FDA, by law, serving sizes must be based on amounts of foods and beverages that people are actually eating, not what they should be eating. This is a legal requirement, not a suggestion, and it's also why serving sizes were revised in recent years: the FDA explained that how much people eat and drink has changed since the previous serving size requirements were published in 1993.
This update changed things in both directions. The FDA specifically notes that some serving sizes increased and others decreased because serving sizes must be based on amounts of food and drink that people typically consume. One concrete example the FDA gives: the reference amount used to set a serving of ice cream was previously half a cup, and is now two-thirds of a cup.
Why this matters when comparing products
Because serving sizes are set per category based on typical consumption, not standardized to one universal amount, two different brands within the same food category should use comparable serving sizes, which makes direct label comparisons more reliable within a category. But comparing across categories, say, a serving of cereal against a serving of ice cream, tells you nothing useful, since the two serving sizes are calibrated to entirely different typical consumption amounts.
Added sugars: a separate number from total sugars
A related labeling detail that often confuses shoppers is the difference between "Total Sugars" and "Added Sugars" on the same label.
According to the FDA, added sugars include sugars added during food processing, such as sucrose or dextrose, sugars from syrups and honey, and sugars from concentrated fruit or vegetable juices. They do not include sugars that occur naturally in foods like milk, fruit, and vegetables.
The Daily Value for added sugars is set at 50 grams per day, based on a 2,000-calorie diet. This number has its own %DV line on the label, separate from total sugars, because total sugars currently has no FDA-assigned Daily Value at all, since there's no single recommended maximum for total sugar intake the way there is for added sugars specifically.
Reading the "includes" language correctly
Labels typically phrase the added sugars line as "Includes [X]g Added Sugars" nested under the Total Sugars line. According to the FDA, this phrasing indicates that added sugars are already counted within the total sugars number, not listed as an extra amount on top of it.
As a worked example from the FDA's own guidance: a container of yogurt with added sweeteners might list a Total Sugars amount that includes 7 grams of Added Sugars and 8 grams of naturally occurring sugars, for a combined total of 15 grams of sugar. The 7 grams of added sugars is the number used to calculate that line's %DV; the other 8 grams, from naturally occurring sugar, isn't flagged separately anywhere else on the label.
Single-ingredient sugars have different rules
Packages of pure, single-ingredient sugars and syrups, such as table sugar, maple syrup, or honey, follow a slightly different rule. According to the FDA, these products are not required to list the number of grams of added sugars, but they are still required to include the percent Daily Value for added sugars. This means a bottle of honey might show a %DV for added sugars without a corresponding gram number next to it, which is intentional, not a labeling error.
Why serving size and added sugars should be checked together
If you are comparing two packaged snacks, checking only the %DV for added sugars without confirming the serving size first can be misleading. A product with a smaller serving size might show a lower added sugars percentage simply because the serving itself is smaller, not because the product is actually lower in sugar per comparable amount. Checking both numbers side by side, serving size in grams or the stated household measure, and the added sugars %DV for that same serving, gives a more accurate comparison than looking at either number alone.
Key takeaways
- US serving sizes are legally required to reflect what people actually eat, not a health recommendation, and were updated based on more recent consumption data.
- Serving size changes can go in either direction. Some categories' reference amounts increased, others decreased, when the FDA updated the standards.
- Added sugars have their own Daily Value of 50 grams per day and their own %DV line, separate from total sugars, which has no assigned Daily Value.
- The word "includes" before Added Sugars on a label means that number is already counted within the Total Sugars figure, not added on top of it.
- Single-ingredient sugars and syrups must show the %DV for added sugars but are not required to list the gram amount.