Considering these disparate definitions, the varying estimates of market size should come as no surprise. Some include products not able to make substantiated health claims, while others may choose to include inherently healthful products (oatmeal, for instance). With its strict definition, Mintel estimates the 2003 functional food market at approximately $4.6 billion, a total that has grown an average of more than 10% annually since 1998.
In that time, convenience-oriented products have flooded all areas of the food and beverage industry, and foods pairing that trait with healthful benefits posted the largest gains. Functional bars, for example, enjoyed strong sales, as sales in the bars, candy and snacks segment grew more than 380%. This phenomenal growth can be credited mostly to bar sales, and Mintel regards bars as a functional segment embraced by mainstream consumers.