A Theoretical Analysis Examining the Construct of a Pound of Fat Equaling 3,500 Kilocalories

Abstract

PURPOSE: The caloric deficit required for a pound of body weight loss is reported to be 3,500 kilocalories (Wishnofsky, 1960). However, published articles, textbooks, and professional organizations equate a pound of fat mass loss to 3,500 kilocalories (Applegate, 2011; Mayo Clinic, 2012; Kravitz, 2007; Cerrato, 1987). The purpose was to perform a theoretical review pertaining to caloric deficits required for equivalent changes in body composition, body weight, and fat mass loss. METHODS: An online database search was performed using key words such as adipose tissue, adipose cell, body composition, body weight loss, fat mass loss, adipose loss, diet, direct calorimetry, and 3,500 calories. 43 articles met the inclusion and exclusion criteria, 28 of which were used for calculating caloric equivalents. The differences in caloric deficit required for a pound of body weight loss, adipose tissue loss, and fat mass loss was compared to the calculated theoretical caloric equivalent for a pound of fat mass loss. A percent error measurement was calculated between the theoretical caloric equivalent for a pound of fat mass loss to the caloric equivalents for a pound of body weight loss, adipose tissue loss, and fat mass loss. RESULTS: The most valid theoretical equivalent for a pound of fat was calculated at 4,423.90 kilocalories (Péronnet & Massicotte, 1991) based on in vivo extraction of human intracellular lipid samples. The calculated percent errors between the theoretical caloric equivalent for a pound of fat mass and published, accepted values for a pound of body weight loss, dietary lipid loss, adipose tissue loss, and fat mass loss were 20.88%, 7.65%, 15.23%, and 20.88%, respectively. CONCLUSIONS: Studies and professional organizations have equated a pound of body weight loss to 3,500 kilocalories, a pound of adipose tissue to 3,750 kilocalories, and a pound of fat mass to 3,500 kilocalories (Wishnofsky, 1960; Dietary Guidelines for Americans, 2010; AHA, 2010, 2014; Applegate, 2011; Mayo Clinic, 2012; Brown, 2001; McArdle, 2010). Contrary to this, a pound of fat mass loss is equal to 4,423.90 kilocalories, and this severely underestimates the caloric values needed to achieve desired fat mass loss. The use of the proper caloric value for fat mass loss has the potential to improve recommendations for achieving healthy body fat values.