J Clin Endocrin Metab. First published ahead of print January 2, 2007 as doi:10.1210/jc.2006-2184
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Effect of calorie restriction with or without exercise on body composition and fat distribution Short title: Calorie restriction vs. exercise on body composition Authors: Leanne M Redman, Leonie K Heilbronn, Corby K Martin, Anthony Alfonso, Steven R Smith, Eric Ravussin for the Pennington CALERIE team. Affiliation: Pennington Biomedical Research Center, Baton Rouge, LA, 70808 Corresponding Author Eric Ravussin 6400 Perkins Rd, Baton Rouge, LA 70808 Ph: 225 763 3186, Fax: 225 763 3030, Email:
[email protected]
Key Words: caloric restriction, exercise, fat distribution Abbreviations: CR, caloric restriction; CR+EX, caloric restriction plus exercise; FM: fat mass; FFM, fat-free mass; VAT, visceral adipose tissue; SAT, subcutaneous adipose tissue; DSAT, deep subcutaneous adipose tissue; SSAT, superficial subcutaneous adipose tissue. Disclosure summary: The authors have nothing to disclose Support: This work was supported by U01 AG20478 (ER). LMR is supported by a Neil Hamilton-Fairley Training Fellowship awarded by the NHMRC of Australia (ID 349553). Clinical trial registration number: CALERIE, NCT00099151 (clinicaltrials.gov) Number of words (3946), number of words (217), number of tables (2) and figures (2)
Copyright (C) 2007 by The Endocrine Society
2 Abstract 2 Context. There is debate over the independent and combined effects of dieting and increased 4
physical activity on improving metabolic risk factors (body composition and fat distribution). Objective. Conduct a randomized controlled trial (CALERIE) to test the effect of a 25% energy
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deficit by diet alone or diet plus exercise for 6 months on body composition and fat distribution. Design. Randomized controlled trial. Setting: Institutional Research Center. Participants.
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Thirty-five out of 36 overweight but otherwise healthy participants (16M/19F) completed the study. Intervention. Participants were randomized to either control (healthy weight-maintenance
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diet, n=11), calorie restriction (CR: 25% reduction in energy intake, n=12) or caloric restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise
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energy expenditure, n=12) for 6 months. Main outcome measures. Changes in body composition by DXA and changes in abdominal fat distribution by multislice CT. Results. The
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calculated energy deficit across the intervention was not different between CR and CR+EX. Participants lost ~10% of body weight (CR:-8.3±0.8, CR+EX:-8.1±0.8kg, p=1.00), ~24% of fat
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mass (CR:-5.8±0.6, CR+EX:-6.4±0.6kg, p=0.99), and 27% of abdominal visceral fat (CR:0.9±0.2, CR+EX:0.8±0.2kg, p=1.00). Both whole body and abdominal fat distribution were
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not altered by the intervention. Conclusion. Exercise plays an equivalent role to CR in terms of energy balance; however it can also improve aerobic fitness which has other important
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cardiovascular and metabolic implications.
3 A growing body of literature demonstrates that in comparison with a dietary restriction 2
intervention alone, exercise, accompanied with or without weight loss can lead to favorable changes in body composition including a reduction in abdominal adiposity (1-4). It is therefore
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reasonable to hypothesize, when exercise is included in a weight loss therapy, greater improvements in body composition and metabolic outcomes may be evident. Few randomized
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controlled trials, however, have specifically tested this hypothesis and compared the metabolic responses of a dietary restriction intervention to a dietary restriction plus exercise intervention.
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Collectively these reports indicate that exercise, when combined with dietary restriction, leads to similar reductions in weight (4-8) but more substantial improvements in glucose tolerance (9,
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10), lipoprotein profiles (6-8, 11, 12) and the risks associated with coronary heart disease (8, 11). There is debate however, regarding the change in fat mass. One study using hydrostatic
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weighing (8) reported an additional 80% reduction in fat mass when exercise was added to dietary restriction while others have reported no difference (5, 6, 10). Furthermore only one
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study used dual x-ray absorptiometry (7) and to our knowledge none have assessed total or abdominal fat distribution by computed tomography or magnetic resonance imaging. Therefore
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the important role of these interventions on fat depots and their relationship to metabolic outcomes cannot be explained in these studies.
18 A combined exercise and dietary restriction intervention could further enhance the metabolic 20
effects of a diet-only intervention through exercise-mediated lipolysis in adipose tissue and mitochondrial biogenesis and improved glucose uptake in skeletal muscle. In most of the
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randomized controlled trials mentioned above (5-12), the degree of dietary restriction applied to the treatment arms (diet only or diet + exercise) was carefully matched, with the exercise
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component added on top. However, the exercise while supervised (in most cases) was not designed to achieve a pre-determined energy expenditure nor was it quantified throughout the
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intervention in terms of energy cost. Therefore, the total energy deficit applied to the diet + exercise groups was larger than that of the diet-only group explaining, at least in part, the
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observed enhanced metabolic responses in the exercise groups. There is a need, therefore to clarify whether dietary restriction when combined with exercise leads to greater improvements in
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body composition and fat distribution, than calorie restriction alone when the total energy deficit is carefully matched between groups. Therefore, a key secondary aim of CALERIE, a
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randomized controlled trial designed to study the effects of calorie restriction on metabolic adaptation in overweight men and women (13) was to investigate and compare the changes in
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body composition and fat distribution. In this study, a 25% energy restriction was prescribed by diet only or diet combined with exercise for 6 months and both energy intake and energy
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expenditure were rigorously controlled and monitored. We hypothesized that changes in body composition and abdominal fat would be enhanced during a caloric restriction intervention that
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combined dieting and exercise.
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Subjects and Methods Subjects and screening. Healthy, overweight (25 ≤ BMI < 30) men (25 –
