There is variability in the pattern of weight change in response to a weight loss intervention (i.e., slowing of subsequent weight loss, cessation of weight loss, weight regain). A reduction in resting energy expenditure (REE) may partially explain the observed variability. Few studies have examined the effect of initial weight loss on change in REE. PURPOSE: To examine the change in REE in response to weight loss across a 4-week period in overweight and obese males and females. METHODS: Thirty-seven subjects (body mass index 25.0-39.9 kg/m2; males = 14, females = 23) participated in a 4-week intervention with random assignment to an Experimental Group or a no treatment Control Group. The experimental group was instructed to reduce energy intake to 1200-1500 kcal/d and participate in 100 min/wk of moderate aerobic exercise. The control group was instructed to maintain current eating and exercise behaviors. Assessments of body weight, body composition, and REE were conducted at 0 and 4 weeks. REE was expressed as absolute REE (kcal/d), REE relative to body weight, (kcal/kg/d), REE relative to lean body mass (kcal/kgLBM/d). RESULTS: Thirty-five subjects completed the study (94.6%). There were significant differences (p<0.05) for change in outcomes between the experimental and control groups for body weight (-3.3+1.7 vs. 0.6+1.1 kg) lean body mass (-0.6+0.9 vs. 0.2+0.9 kg), absolute REE (-205.8+193.0 vs. -11.4+ 140.6 kcal/d), and REE relative to lean body mass (-3.3+2.9 vs. -0.4+2.6 kcal/kgLBM/d). There was a trend toward a significant difference between the groups (p = .07) for REE relative to body weight (-1.4+1.9 vs. -0.3+1.5 kcal/kg/d). When the groups were combined, there was a correlation between change in REE and change in body weight was r=0.41 (p<.05), and change in REE and change in lean body mass was r=0.44 (p<.01). CONCLUSIONS: Results indicate that absolute and relative REE are significantly reduced in response to weight loss over a 4-week period. The modest correlations between change in REE and both body weight and lean body mass may suggest that additional physiological mechanisms influence REE during the acute phase of weight loss.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-10202006-151514 |
| Date | 29 January 2007 |
| Creators | Kowallis, Ruth Ann |
| Contributors | Amy D. Otto, PhD, Elizabeth F. Nagle, PhD, Fredric L. Goss, PhD, John M. Jakicic, PhD, Elaine N. Rubinstein |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-10202006-151514/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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