title: Effect of weight loss on maximal fat oxidation rate in obese men.
abstract: CONCLUSIONS
  
  
  
  BACKGROUND
  The hallmark features of obesity include insulin resistance and an impaired ability to oxidize lipids. As compared to exercise training, it remains relatively unclear if diet-induced weight loss can also induce fat metabolism. This study was undertaken to examine the effects of diet-induced weight loss on fat metabolism during a single session of exercise in middle-aged obese men.
  
  
  METHODS
  Fifteen obese men who were otherwise healthy (average age of 53.5 ± 6.9 yr and average body mass index of 27.8 ± 1.6 kg/m(2)) participated in a 12-wk weight loss program primarily consisting of dietary modification. Maximal fat oxidation (MFO) rates, MFO per lean body mass (MFOLBM) and insulin resistance (HOMA-IR) were measured before and after the program. Participants performed a 24-min graded exercise test on a cycle ergometer, with 15-W increments every 4 min. Expired gas analysis was performed by indirect calorimetry, and nonprotein respiratory quotient equations were used to calculate fat oxidation rates.
  
  
  RESULTS
  The weight (-8.3 ± 3.8 kg), fat mass (-4.5 ± 1.9 kg), and lean body mass (-3.8 ± 2.4 kg) (P < 0.001 for all measurements) of the participants were decreased at the end of the 12-wk program. The MFO tended to increase by 19% (P = 0.08) and MFOLBM significantly increased by 28.8% (P = 0.02). Although insulin resistance also significantly decreased by 49% (P < 0.001), changes in fat oxidation variables did not correlate with changes in insulin resistance.
  
  
  CONCLUSIONS
  Diet-induced weight loss improves fat metabolism with the improvement in insulin resistance.:
authors: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan. Electronic address:tsujimoto@stat.taiiku.tsukuba.ac.jp.
authors: Takehiko
authors: T
authors: Tsujimoto
authors: Japan Society for the Promotion of Science, Tokyo, Japan.
authors: Hiroyuki
authors: H
authors: Sasai
authors: Faculty of Sport Sciences, Waseda University, Saitama, Japan.
authors: Masashi
authors: M
authors: Miyashita
authors: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan.
authors: Miki
authors: M
authors: Eto
authors: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan.
authors: Rina
authors: R
authors: So
authors: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan.
authors: Hiroyuki
authors: H
authors: Ohkubo
authors: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan.
authors: Kiyoji
authors: K
authors: Tanaka