Interesting Study:Exercise, Calorie Restriction with/without Weight Loss

This is a very interesting paper that teasing out the differences
between exercise, calorie restriction with and without weight loss.

The results were not what I would have predicted.

randyf

The Impact of Exercise Training Compared to Caloric Restriction on
Hepatic
and Peripheral Insulin Resistance in Obesity.
Coker RH, Williams RH, Yeo SE, Kortebein PM, Bodenner DL, Kern PA,
Evans WJ.
J Clin Endocrinol Metab. 2009 Oct 6. [Epub ahead of print]
PMID: 19808853

Context: It has been difficult to distinguish the independent effects
of
caloric restriction versus exercise training on insulin resistance.

Objective: Utilizing metabolic feeding and supervised exercise
training, we
examined the influence of caloric restriction vs. exercise training
with and
without weight loss on hepatic and peripheral insulin resistance.

Design, Participants, and Intervention: Thirty-four obese, older
subjects
were randomized to: caloric restriction with weight loss (CR),
exercise
training with weight loss (EWL), exercise training without weight loss
(EX),
or controls. Based on an equivalent caloric deficit in EWL and CR, we
induced matched weight loss. Subjects in the EX group received
caloric
compensation. Combined with [6,6(2)H2]glucose, an octreotide,
glucagon,
multistage insulin infusion was performed to determine suppression of
glucose production (SGP) and insulin-stimulated glucose disposal
(ISGD).
Computed tomography scans were performed to assess changes in fat
distribution.

Results: Body weight decreased similarly in EWL and CR, and did not
change
in EX and controls. The reduction in visceral fat was significantly
greater
in EWL (-71±15 cm(2)) compared to CR and EX. The increase in SGP was
also
almost 3-fold greater (27±2%) in EWL. EWL and CR promoted similar
improvements in ISGD [+2.5±0.4 and 2.4±0.9 mg/kg fat-free mass (FFM)/
min],
respectively.

Conclusions: EWL promoted the most significant reduction in visceral
fat and
the greatest improvement in SGP. Equivalent increases in ISGD were
noted in
EWL and CR, whereas EX provided a modest improvement. Based on our
results,
EWL promoted the optimal intervention-based changes in body fat
distribution
and systemic insulin resistance.
.

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