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Energy Expenditure

EE: Diurnal Variation: Within 24-Hours (2005)

Glossary of Terms





The passage of a substance through some surface of the body into body fluids and tissues; Thus, small intestine absorption is where the most important absorption of products of digestion occur. In literature, a RMR measure taken in a post-absorptive state typically describes when a person has fasted overnight or for a recommended period after eating. This measurement represents a state with minimal heightened metabolic activity due to prior physical, mental or stress-related activities.


An individual going without food; Energy requirements of body metabolism during fasting are supplied by the oxidization of fats which, if glucose is not supplied, results in the products of incomplete fat combustion such as fatty acids, diacetic acid, and acetone.  This typically describes individuals who haven’t eaten for >/= 8 hours).


A prefix term meaning behind or after.


A period from >6 hours after eating and < 8hours of fasting.


A period occurring after eating a meal; see Subquestion #1 i, diet-induced thermogenesis, for additional information.

Postcibal (see postprandial)

A PubMed term used to describe time occurring after meals (i.e., cibum = food)


                Coefficient of variation- A measure of variability that is the ratio of the standard deviation to the mean, expressed as a percentage:

                CV = standard deviation (s)/ Mean (set of individual replicate measures or sample mean) X 100.

An intra-individual coefficient of variation reports measurement imprecision or biological variability within an individual.  Thus, within-individual RMR changes reports a ratio between the standard deviation from a set of replicate measurements made on an individual divided by the mean of individual measurements that is multiplied by 100 to convert to a percentage.

An inter-individual coefficient of variation reports measurement imprecision or biological variability between individuals and is an index of agreement between individuals.

                Relative difference is a measure of group variability and reports the average difference between group mean RMR measures relative to the initial group mean RMR.  This is a ratio of group mean differences to the initial group mean RMR multiplied by 100 to convert to a percentage.