Critical evaluation of energy intake using the Goldberg cut-off for energyintake : basal metabolic rate. A practical guide to its calculation, use and limitations

OBJECTIVES: To re-state the principles underlying the Goldberg cut-off for identifying under-reporters of energy intake, re-examine the physiological principles and update the values to be substituted into the equation for ca lculating the cut-off, and to examine its use and limitations. RESULTS: New values are suggested for each element of the Goldberg equation . The physical activity level (PAL) for comparison with energy intake:basal metabolic rate (EI:BMR) should be selected to reflect the population under study; the PAL value of 1.55 x BMR is not necessarily the value of choice. The suggested value for average within-subject variation in energy intake is 23% (unchanged), but other sources of variation are increased in the lig ht of new data. For within-subject variation in measured and estimated BMR, 4% and 8.5% respectively are suggested (previously 2.5% and 8%), and for t otal between-subject variation in PAL, the suggested value is 15% (previous ly 12.5%). The effect of these changes is to widen the confidence limits an d reduce the sensitivity of the cut-off. CONCLUSIONS: The Goldberg cut-off can be used to evaluate the mean populati on bias in reported energy intake, but information on the activity or lifes tyle of the population is needed to choose a suitable PAL energy requiremen t for comparison. Sensitivity for identifying under-repeaters at the indivi dual level is limited. In epidemiological studies information on home, leis ure and occupational activity is essential in order to assign subjects to l ow, medium or high PAL levels before calculating the cut-offs. In small stu dies, it is desirable to measure energy expenditure, or to calculate indivi dual energy requirements, and to compare energy intake directly with energy expenditure.