Recommendations Summary
AWM: Encourage Physical Activity 2014
Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.
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Recommendation(s)
AWM: Encourage Physical Activity for Weight Loss
For weight loss, the registered dietitian nutritionist (RDN) should encourage physical activity as part of a comprehensive weight management program, individualized to gradually accumulate 150 to 420 minutes or more of physical activity per week, depending on intensity, unless medically contraindicated. Physical activity less than 150 minutes per week promotes minimal weight loss, physical activity more than 150 minutes per week results in modest weight loss of approximately 2kg to 3kg, and physical activity of more than 225 to 420 minutes per week results in 5kg to 7.5kg weight loss, and a dose–response exists.
Rating: Consensus
ImperativeAWM: Encourage Physical Activity for Weight Maintenance
For weight maintenance, the registered dietitian nutritionist (RDN) should encourage physical activity as part of a comprehensive weight management program, individualized to accumulate 200 to 300 minutes or more of physical activity per week, depending on intensity, unless medically contraindicated. Some studies support the value of approximately 200 to 300 minutes per week of physical activity during weight maintenance to reduce weight regain after weight loss.
Rating: Consensus
Imperative-
Risks/Harms of Implementing This Recommendation
Intense physical activity in some overweight and obese individuals may contribute to disability or death; thus, consultation with a physician prior to beginning an exercise program should be recommended.
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Conditions of Application
Unless medically contraindicated.
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Potential Costs Associated with Application
Costs of medical nutrition therapy (MNT) sessions vary; however, MNT sessions are essential for improved outcomes.
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Recommendation Narrative
From the American College of Sports Medicine Position Stand (2009)
- Physical activity to prevent weight gain: Physical activity of 150 to 250 minutes per week with an energy equivalent of 1, 200kcal to 2000kcal per week will prevent weight gain greater than 3% in most adults. Evidence Category A.
- Physical activity for weight loss: Physical activity less than 150 minutes per week promotes minimal weight loss, physical activity greater than 150 minutes per week results in modest weight loss of approximately 2kg to 3kg, physical activity greater than 225 to 420 minutes per week results in 5kg to 7.5kg weight loss and a dose–response exists. Evidence Category B.
- Physical activity for weight maintenance after weight loss: Some studies support the value of approximately 200 to 300 minutes per week of physical activity during weight maintenance to reduce weight regain after weight loss, and it seems that ‘‘more is better.’’ However, there are no correctly designed, adequately powered, energy balance studies to provide evidence for the amount of physical activity to prevent weight regain after weight loss. Evidence Category B.
- Lifestyle physical activity is an ambiguous term and must be carefully defined to evaluate the literature. Given this limitation, it seems lifestyle physical activity may be useful to counter the small energy imbalance responsible for obesity in most adults. Evidence Category B.
- Physical activity and diet restriction: Physical activity will increase weight loss if diet restriction is modest but not if diet restriction is severe
- Resistance training for weight loss: Research evidence does not support resistance training as effective for weight loss with or without diet restriction. There is limited evidence that resistance training promotes gain or maintenance of lean mass and loss of body fat during energy restriction and there is some evidence resistance training improves chronic disease risk factors (i.e., HDL-C, LDL-C, insulin, blood pressure). Evidence Category B.
For Weight Maintenance (Less than 3% Change in Weight)- There is a favorable and consistent effect of aerobic PA on achieving weight maintenance (Strong). The evidence is less consistent for resistance training, in part, because of the compensatory increase in lean mass (Moderate), and the smaller volumes of exercise employed.
- Aerobic PA has a consistent effect on achieving weight maintenance (Strong); resistance training has a moderate effect (Limited)
- There is no evidence for a dose-response effect for PA and weight maintenance, as it has not been specifically tested
- The optimal amount of physical activity needed for weight maintenance over the long term is unclear. However, there is clear evidence that physical activity provides benefit for weight stability. There is a great deal of inter-individual variability with physical activity and weight stability, and many persons may need more than 150 minutes of moderate-intensity activity per week to maintain weight. Data from recent well-designed RCTs lasting up to 12 months indicate that aerobic physical activity performed to achieve a volume of 13 to 26 MET-hours per week is associated with approximately a 1% to 3% weight loss, which is generally considered to represent weight stability. A total of 13 MET-hours per week is approximately equivalent to walking at four miles per hour for 150 minutes per week or jogging at six miles per hour for 75 minutes per week.
- Accumulation of energy expenditure due to PA is what is important to achieving energy balance (Strong). Accumulation of PA can be obtained in short multiple bouts or one long bout to meet PA expenditure goals for weight maintenance (Moderate).
- The amount of weight lost due to PA (alone) is dependent on the volume of activity, and few studies have used a volume of PA large enough to achieve a 5% weight loss. If an isocaloric diet is maintained throughout the PA intervention, weight loss is similar to what is observed for dietary interventions and clearly exceeds 5% (Strong).
- PA alone has no effect on achieving a 5% weight loss, except at very large volumes of PA or when an isocaloric diet is maintained throughout the PA intervention (Strong)
- There is a clear, consistent dose-response effect of aerobic PA on weight loss (Strong)
- There are clear, consistent data that a large volume of physical activity is needed for weight loss in the absence of concurrent dietary changes. Physical activity equivalent to 26kcal per kg (1, 560 MET-minutes) or more per week is needed for weight loss of 5% or greater (Moderate); less amounts of weight loss are seen with smaller amounts of physical activity. This relatively high volume of physical activity is equivalent to walking about 45 minutes per day at four miles per hour or about 70 minutes per day at three miles per hour, or jogging 22 minutes per day at six miles per hour.
- There is evidence that accumulation of PA independent of distribution of PA bouts is what is important for weight loss (Limited); however, it is difficult accumulate large volumes of PA without concentrated bouts.
- PA promotes less weight regain after a period of significant weight loss (Moderate)
- Aerobic PA has a reasonably consistent effect on weight maintenance following weight loss (Moderate)
- A dose-response is present; those performing the larger volumes of aerobic PA had less weight regain (Moderate)
- PA equivalent to 30kcal per kg per week or more. This is equivalent to walking about 50 minutes per day at about four miles per hour, 80 minutes per day at about three miles per hour or jogging for 25 minutes per day at six miles per hour (Moderate)
- There is reasonable evidence that accumulation of PA independent of distribution of bouts is what is important for weight stability following weight loss (Limited); however, it is difficult accumulate large volumes of PA without concentrated bouts.
- A decrease in total abdominal adiposity and intra-abdominal adiposity is associated with aerobic PA (Moderate to Strong). The effect is less well described for resistance training (Weak).
- Aerobic PA has a consistent effect on total abdominal adiposity and a smaller effect on intra-abdominal adiposity (Strong). Resistance training has a small and less consistent effect on total abdominal and intra-abdominal adiposity (Limited).
- Larger, well-designed studies report a dose-response relationship for aerobic PA related to abdominal obesity measures (Moderate)
- Aerobic physical activity in the range of 13kcal to 26kcal per kg per week results in decreases in total and abdominal adiposity consistent with improved metabolic function. A total of 13 MET-hours per week is approximately equivalent to walking at four miles per hour for 150 minutes per week or jogging at six miles per hour for 75 minutes per week. However, larger volumes of physical activity (e.g., 42kcal per kg per week) result in decreases in intra-abdominal adipose tissue that are three to four times that seen with 13kcal to 26kcal per kg per week of physical activity.
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Recommendation Strength Rationale
- The ADA Adult Weight Management Work Group concurs with the references cited
- The American College of Sports Medicine Position Stand evidence statements given are Evidence Categories A and B
- The Physical Activity Guidelines Advisory Committee recommendations given are Strong, Moderate, Weak and Limited.
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Minority Opinions
Consensus reached.
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Risks/Harms of Implementing This Recommendation
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Supporting Evidence
The recommendations were created from the evidence analysis on the following questions. To see detail of the evidence analysis, click the blue hyperlinks below (recommendations rated consensus will not have supporting evidence linked).
- References
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References not graded in Academy of Nutrition and Dietetics Evidence Analysis Process
Carpenter RA, Schwartz J. A Physical Activity Toolkit for Registered Dietitians: Utilizing Resources of Exercise is Medicine. Academy of Nutrition and Dietetics, 2013. Accessed at: http://wmdpg.org/wp-content/uploads/2013/06/WMDPG-Navigating-an-Essential-Resource-Article.pdf.
Donnelly JE, Blair SN, Jakicic JM, Manore MM, Rankin JM, Smith BK; American College of Sports Medicine. American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc. 2009; 41(2): 459-471.
Physical Activity Guidelines Advisory Committee. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services, 2008.
Shaw K, Gennat H, O'Rourke P, Del Mar C. Exercise for overweight or obesity. Cochrane Database Syst Rev. 2006 Oct 18; (4): CD003817.