Every % Daily Value on a nutrition label rests on decades of nutrition research condensed into reference numbers. Here's where those numbers come from.
The RDAs: wartime origins
The story starts in 1941, when the U.S. National Academy of Sciences established the first Recommended Dietary Allowances (RDAs) — intake levels of nutrients considered adequate for most healthy people. They were developed partly out of wartime concern about the nutritional fitness of the population and have been revised periodically ever since as science advanced.
From RDAs to Daily Values
When the Nutrition Facts label was created in the early 1990s, the FDA needed a single, simple reference for the label. It developed Daily Values (DVs) — consumer-friendly reference amounts derived from the RDAs and related standards. Two components fed into them: Reference Daily Intakes (for vitamins and minerals) and Daily Reference Values (for nutrients like fat, sodium, and carbohydrate).
The 2,000-calorie reference
The Daily Values on the label are calibrated to a 2,000-calorie-a-day diet, chosen as a round reference figure. That's why the footnote notes that '2,000 calories a day is used for general nutrition advice' — your personal needs may differ, but the reference keeps products comparable.
Updated in 2016
As part of the 2016 label redesign, the FDA updated many Daily Values to reflect newer science. Sodium's DV changed, fiber's was revised, and — most notably — a Daily Value for added sugars was established at 50 grams, enabling the new added sugars %DV. These updates keep the percentages on the label aligned with current dietary recommendations.