The efficacy of exercise in the treatment of established obesity
DOI:
https://doi.org/10.14288/hfjc.v12i3.279Abstract
______________________________________________________________
Objective. The objective of this narrative review was to examine cross-sectional empirical data on the efficacy of adequate doses of daily physical activity in the treatment of established obesity. Methods. Information obtained from Ovid/Medline and Google Scholar through to June 2019 was supplemented by a search of the author's extensive personal files. Results. Randomized controlled trials have shown a small but consistent effect of exercise programmes in reducing the body mass and body fat content of the obese. Some non-randomized trials have adopted larger volumes of exercise (2-4 MJ/day), and weight losses of 10 kg or more have then been observed. Dieting has generally given a greater weight loss than exercise, but some of this apparent advantage has reflected a greater loss of lean tissue. Changes in lean tissue mass have under-estimated the beneficial impact of exercise programmes by 2-3 kg, while exaggerating the benefits of dieting by 2-3 kg. Fat loss seems to occur a little more easily in men than in women, and it is also easier to mobilize abdominal fat than subcutaneous fat. The minimal dose of physical activity recommended by public health authorities seems insufficient to deal with established obesity; adults need 150-250 minutes of exercise per week, incurring an additional weekly energy expenditure of 4.8-8.0 MJ, and children may require even larger doses of activity to counter obesity. High intensity programmes save time and may be somewhat more effective for any given energy expenditure than longer periods of moderate activity. A combination of dietary restraint and heavy exercise can cause an 8.5 kg loss of fat over 8 weeks. However, long-term adherence to high intensity programmes is more problematic. It may be helpful to split a single session of aerobic activity into several shorter segments. Causes of a limited response to exercise include an insufficient exercise prescription, poor programme adherence, and a compensatory increase of food intake, compounded by reductions in resting metabolic rate, spontaneous leisure activity and NEAT. Meta-analyses have typically shown weight and fat losses of around 10 kg with 3 months of combined dieting and exercise, but in a few instances much greater weight losses have been reported. Moderate exercise sessions have sometimes added little to dieting alone, but it remains unclear whether more rigorous physical activity programmes might lead to a greater fat loss. Exercise is helpful in preserving lean tissue; it also confers many ancillary health benefits such as enhanced cardio-respiratory fitness, and it may limit the regain of weight after the completion of formal treatment. Resistance exercise is particularly helpful in conserving lean tissue. In a long-term perspective, lifestyle activities may more effective than a formal exercise programme. Much of initial weight loss is often regained within a year, but continued exercise and dieting conserve at least 3 kg of the initial weight reduction. Conclusions. Moderate exercise alone has less effect upon obesity than rigorous dieting, but benefits are larger if the exercise dose can be increased. Exercise helps to conserve lean tissue, and plays an important role in weight maintenance. The challenges to health professionals are to develop safe methods of reaching an effective dose of exercise in those who are obese, and in sustaining the enthusiasm of such individuals for an active lifestyle once initial weight goals have been attained.
Downloads
Published
How to Cite
Issue
Section
License
Terms of Publication
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the Health & Fitness Journal of Canada’s right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
- The Contributor (author(s)) represents and guarantees that the Contributor is the sole proprietor of the work and the Contributor has full power to make this Agreement and grant that the work does not infringe the copyright or other proprietary right of any other person; and the work contains no libellous or other unlawful matter and makes no improper invasion of the privacy of any other person. The Contributor also represents and is responsible for the accuracy of the work.
- The Contributor will read, correct, and return promptly galleys and page proofs to the Editor (or designate). The Contributor will be responsible for the completeness and accuracy of these corrections. If the Contributor does not return galleys and page proofs within the schedule agreed upon with the Editor (or designate), the Publisher may proceed without the Contributor corrections.
- When applicable, the Contributor agrees to obtain written permissions and letters of agreement for all matter contained in the work that is protected by existing copyright, paying any permission fees for the use of text or illustrations controlled by others, and furnishing the Publisher with written evidence of the copyright owner’s authorization to use the material.
- When applicable, the Contributor agrees to obtain written permission for inclusion of any photographic materials involving a human subject, and provide the Publisher with written evidence of the subject’s authorization to use this material. In the case of subjects who have not reached the age of majority, the Contributor agrees to obtain and furnish the Publisher with written permission from the parent and/or legal guardian.
- The Contributor may draw on and refer to material in the work in preparing other articles for publication in scholarly and professional journals and papers for delivery at professional meetings, provided that credit is given to the work and to the Publisher.
- This agreement may not be changed unless the Contributor and the Publisher agree to the change by means of a formal addendum signed by the Contributor and the Publisher’s representative.
- This agreement shall be construed and governed according to the laws of the province of British Columbia and shall be binding upon the parties hereto, their heirs, successors, assigns, and personal representatives. Should any formal proceedings related to this agreement be brought, such formal proceeding may be brought only in the province of British Columbia.
By submitting an article to the Health & Fitness Journal of Canada the Contributor has accepted and agreed to all terms outlined in the copyright notice.