Exercise-induced reduction in obesity and insulin resistance in women: a randomized controlled trial.
OBJECTIVE
To determine the effects of equivalent diet- or exercise-induced weight loss and exercise without weight loss on subcutaneous fat, visceral fat, and insulin sensitivity in obese women.


METHODS
Fifty-four premenopausal women with abdominal obesity [waist circumference 110.1 +/- 5.8 cm (mean +/- SD)] (BMI 31.3 +/- 2.0 kg/m2) were randomly assigned to one of four groups: diet weight loss (n = 15), exercise weight loss (n = 17), exercise without weight loss (n = 12), and a weight-stable control group (n = 10). All groups underwent a 14-week intervention.


RESULTS
Body weight decreased by approximately 6.5% within both weight loss groups and was unchanged in the exercise without weight loss and control groups. In comparison with controls, cardiorespiratory fitness improved within the exercise groups only (p < 0.01). Reduction in total, abdominal, and abdominal subcutaneous fat within the exercise weight loss group was greater (p < 0.001) than within all other groups. The reduction in total and abdominal fat within the diet weight loss and exercise without weight loss groups was greater than within controls (p < 0.001) but not different from each other (p > 0.05). Visceral fat decreased within all treatment groups (p < 0.008), and these changes were not different from each other. In comparison with the control group, insulin sensitivity improved within the exercise weight loss group alone (p < 0.001).


CONCLUSIONS
Daily exercise without caloric restriction was associated with substantial reductions in total fat, abdominal fat, visceral fat, and insulin resistance in women. Exercise without weight loss was also associated with a substantial reduction in total and abdominal obesity.
Ross
Robert
R
School of Physical and Health Education, Department of Medicine, Division of Endocrinology and Metabolism, Queen's University, Kingston, Ontario, Canada. rossr@post.queensu.ca
Janssen
Ian
I
Dawson
Jody
J
Kungl
Ann-Marie
AM
Kuk
Jennifer L
JL
Wong
Suzy L
SL
Nguyen-Duy
Thanh-Binh
TB
Lee
SoJung
S
Kilpatrick
Katherine
K
Hudson
Robert
R
D000005:Abdomen; D000273:Adipose Tissue; D000328:Adult; D000886:Anthropometry; D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D004038:Diet, Reducing; D002149:Energy Intake; D015444:Exercise; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D018482:Muscle, Skeletal; D009765:Obesity / Q000628:therapy*; D010809:Physical Fitness; D017697:Premenopause; D015431:Weight Loss