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Effect of rapid or slow weight reduction on the body composition and body energy loss in rats
Author(s) -
Maeda Megumi,
Kondo Emi,
Inoue Haruna,
Okamura Koji
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb473
Subject(s) - weight loss , body weight , chemistry , lean body mass , zoology , energy expenditure , urine , endocrinology , medicine , obesity , biochemistry , biology
Rapid weight loss has been shown to result in greater reductions in the lean body mass (LBM) than slow weight loss, suggesting that less body energy is lost with rapid weight reduction due to the lower energy content of lean tissue compared with fat tissue. The aim of this study was to compare the changes in the LBM, fat mass (FM), and body energy loss between rapid and slow weight reduction. Male Sprague‐Dawley rats were divided into a rapid weight reduction group (Rapid, n = 5), which was fasted for 3 days, or a slow weight reduction group (Slow, n = 5), which had its food intake restricted for 13–21 days to achieve a final body weight comparable to that in the Rapid group. All rats were maintained individually in a metabolic chamber to measure energy expenditure. The initial body weight was 688.0 g (standard deviation [SD] 78.1) in the Rapid group and 693.6 g (SD 34.5) in the Slow group. The body weight reduction and total energy expenditure during the experiment were 63.7 g (SD 12.0) and 183.0 kcal (SD 12.8) in the Rapid group and 63.3 g (SD 11.3) and 1241.2 kcal (SD 245.6) in the Slow group, respectively. The metabolizable energy (absorbed energy minus expended energy and excreted energy into urine) during the experiment in the Slow group was 235.3 kcal (SD 90.7). Consequently, the calculated energy loss for body weight loss by 1 kg did not differ significantly between the Rapid group (2943.3 kcal [SD 405.2]) and the Slow group (3628.9 kcal [SD 1072.6]). The estimated decrease in the LBM and FM based on the energy density of lean tissue (1.1 kcal/g) and fat tissue (7.6 kcal/g) was 46.4 g (SD 12.3) and 17.4 g (SD 1.0) in the Rapid group and 37.8 g (SD 10.1) and 25.5 g (SD 12.6) in the Slow group, respectively, with no significant differences observed between the groups. In conclusion, neither the decrease in the LBM or FM nor in the body energy loss due to body weight loss differed significantly between the rats experiencing rapid and slow weight reduction.