Approaches for quantifying energy intake and %calorie restriction during calorie restriction interventions in humans: the multicenter CALERIE study.

Am J Physiol Endocrinol Metab 2012;302:E441-8

Racette SB, Das SK, Bhapkar M, Hadley EC, Roberts SB, Ravussin E, Pieper C, Delany JP, Kraus WE, Rochon J, Redman LM, The CALERIE Study Group