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With approximately 2 out of 3 Americans currently overweight or obese, many continue to come up short on recommendations for certain nutrients such as calcium, magnesium, potassium, vitamin A, vitamin C, vitamin E, and fiber in their diet. Numerous attempts have been made to provide consumers with nutrient-profiling tools, such as manufacturer-specific symbols, to improve dietary selections, but many of the tools have focused on assisting consumers in making single food selections and do not provide guidance about planning total diets. In response to the 2005 Dietary Guidelines Advisory Committee's recommendation for research to define nutrient density, the Nutrient Rich Foods Coalition (NRFC) embarked on the development of a scientifically valid definition of nutrient density and consumer-driven educational tools to communicate the concept of nutrient-rich foods (NRF) to consumers. The science-based, consumer-driven NRF approach to eating may help Americans make multiple small changes in their diet that ultimately lead to better diet quality and significant improvements in public health.

Several mathematical models have been used to describe the deactivation of cracking catalysts by coke. For the case of gas oil cracking under short contact times (less than 20 seconds) it was found, using data from two different experimental reactor units, that an exponential decay function or a power law function could equally represent the data. Both functions are forms of the general hyperbolic decay expression; however, the power law assumes the unrealistic limits of infinite catalyst activity at zero time‐on‐stream and requires two parameters to describe deactivation. This work shows that the simple first order decay function is an effective equation to be used in describing catalyst activity decay for short reaction times.