Integrative Physiology
Obesity (2008) 16, 34–39. doi:10.1038/oby.2007.15
Differences in Daily Energy Expenditure in Lean and Obese Women: The Role of Posture Allocation
Darcy L Johannsen1,3, Gregory J Welk2, Rick L Sharp2 and Paul J Flakoll1,
- 1Department of Food Science and Human Nutrition at Iowa State University, Ames, Iowa, USA
- 2Department of Health and Human Performance, Iowa State University, Ames, Iowa, USA
- 3Present address: Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
Correspondence: Darcy Johannsen, (Darcy.Johannsen@pbrc.edu)
*Deceased.
Received 1 November 2006; Accepted 17 May 2007.
Abstract
Objective:
A low resting metabolic rate (RMR) is considered a risk factor for weight gain and obesity; however, due to the greater fat-free mass (FFM) found in obesity, detecting an impairment in RMR is difficult. The purposes of this study were to determine the RMR in lean and obese women controlling for FFM and investigate activity energy expenditure (AEE) and daily activity patterns in the two groups.
Methods and Procedures:
Twenty healthy, non-smoking, pre-menopausal women (10 lean and 10 obese) participated in this 14-day observational study on free-living energy balance. RMR was measured by indirect calorimetry; AEE and total energy expenditure (TEE) were calculated using doubly labeled water (DLW), and activity patterns were investigated using monitors. Body composition including FFM and fat mass (FM) was measured by dual energy X-ray absorptiometry (DXA).
Results:
RMR was similar in the obese vs. lean women (1601 
109 vs. 1505 109 kcal/day, respectively, P = 0.12, adjusting for FFM and FM). Obese women sat 2.5 h more each day (12.7 3.2 h vs. 10.1 2.0 h, P < 0.05), stood 2 h less (2.7 1.0 h vs. 4.7 2.2 h, P = 0.02) and spent half as much time in activity than lean women (2.6 1.5 h vs. 5.4 1.9 h, P = 0.002).
Discussion:
RMR was not lower in the obese women; however, they were more sedentary and expended less energy in activity than the lean women. If the obese women adopted the activity patterns of the lean women, including a modification of posture allocation, an additional 300 kcal could be expended every day.
