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Many countries have recommendations for the intake of whole grain. In these recommendations, the specific quantities of whole grains to be consumed per day varies considerably (Frølich and Åman 2010; Ferruzzi et al. 2014). Also, recommendations of whole grain products are given in many guidelines internationally, either quantitatively (g) or qualitatively (eat more) (van der Kamp and Lupton 2013). The quantitative recommendation varies between a minimum of 48 g (US) and 75 g (Denmark) of whole grain per day.

Inconsistency in labeling and large variation in the amount of whole grain in products labeled as whole grain foods makes it difficult for the consumers to choose whole grain products. The consumers often believe that a high dietary fibre content is equivalent to high amounts of whole grain, which is not always the case since the content of dietary fibre in different whole grains vary considerably (from about 3% in rice to about 20% in rye). Isolated and synthesized dietary fibre from different sources could also be added to the products and wrongly indicating high whole grain content on the label.

What qualifies as whole grain products varies greatly in different populations and makes it challenging to determine the true intake of whole grain as g per day. Various classifications have been used in different studies such as:

1 whole grains listed as first ingredient on the label

2 dietary fibre rich products

3 products with more than 25% or 50% of whole grain

4 dark bread

The content of whole grain may be based either on dry weight or on fresh weight of the product. Foods with a high content of water will show much lower figure of whole grain than if this figure was based on dry weight. In some countries, declared/labeled content of whole grain is based on the total flour base, not including other food ingredients present in the product. It will therefore be misleading if the content of flour accounts for only a minor part compared to other ingredients in the product.

Today, little information is available on the intake of different whole grain types, which is important since different grain contains different nutrients and bioactive components. This will be a challenge in the future when health effects of individual whole grains will be studied in nutrition and population studies (Biskup et al. 2016). A study on subgroups in Scandinavia showed distinct national differences in the source of whole grain intake (Kyrø et al. 2012) and subsequent epidemiological studies have tried to analyze the role of whole grains from different grains separately in relation to disease outcomes (Wu et al. 2019; Kyrø et al. 2018; Johnsen et al. 2015).