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Whole grains are a diverse group of cereals and pseudocereals that are on one level well defined as ingredients, but at the level of food products, poorly defined due to no universally accepted definition of what constitutes a whole grain food product. This is further clouded by a wide range of definitions used by scientists, regulatory authorities, private labeling initiatives and what is reported “on pack” for food products containing cereals.

In the scientific literature, the use of “whole grains” to identify foods of potential interest for reducing disease risk, first used a cut‐off point of 25% whole grains (as a percent of total weight as consumed) in a product.^(3,4,5) Deciding on a threshold for whether a product would count as being “whole grain” or not was necessary to establish whether there was a relationship between foods containing whole grains and health. However, this also means that a food included as whole grain for the purposes of estimating intake could contain anywhere between 25% and 100% of its total weight as whole grains. A product that contained 26% whole grains would be considered to contribute the same amount of whole grains to overall whole grain intake as a food with 100% whole grain ingredients. Further, using this threshold does not account for products that contain <25% whole grains, so it would not be possible to determine whether such foods make an important contribution to whole grain intake. So while a 25% threshold was a good starting point, as research on whole grains has progressed since the early studies associating whole grain intake with reduced disease risk, it has been necessary to further develop how whole grain intake is estimated and how whole grain content in foods is measured and used to estimate intake.

In 1999, the United States Food and Drug Administration (FDA) allowed a health claim to be made for whole grain foods and cardiovascular disease and some types of cancer. With this health claim came the first set of criteria to define what a whole grain food product was: a food with ≥51% whole grains (by total weight as consumed), low in fat, sugar and salt. Determination of whether a product was whole grain or not was based on the dietary fibre content of wheat – a laudable attempt, but problematic as many commonly consumed cereals have a lower dietary fibre content than wheat – notably rice and corn/maize. The water content of whole grain foods was not addressed, allowing dry foods like RTE breakfast cereal, crackers and pasta to qualify for the FDA health claim much more easily than moist foods like bread. In contrast, a definition developed by the Swedish Nutrition Foundation to support a Swedish health claim for whole grain foods specified that foods needed to have at least 50% whole grain ingredients on a dry weight basis, but that foods could claim “whole grain” on their packaging if they had at least 25% on a dry weight basis, and stated the proportion of whole grains.⁽⁶⁾