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Recently updated guidelines have been published in the medical community, which you may find of interest.
A "metabolic equivalent" 1 is equivalent to a metabolic rate consuming 3.5 milliliters of oxygen per kilogram of body weight per minute, or, to a metabolic rate consuming 1 kilocalorie per kilogram of body weight per hour. For example, you are at 2 MET's when walking at 2 MPH, 4 METs when walking at 5 MPH, 8 to 10 METS when jogging at a fair pace or doing calisthenics, and up to 12 METs when engaging in fast jogging, and other very strenuous fast paced exercises. By convention, 1 MET is used at rest. A MET minute would be the MET multiplied by the amount of minutes that exercise was endured; 500 MET minutes can be obtained by performing fast walking for one hundred minutes, or jogging at 10 METs for fifty minutes. These numbers are an approximate, and tend to be based on a 70 kg man. Of course, there will be variation; so use this as a guideline and not as an absolute.
PA stands for "physical activity".
Please keep in mind that 500 to 1000 MET minutes are suggested for good health; using more will accelerate weight loss with proper dietary restrictions.
Also note that these guidelines suggest that resistance exercises, such as weight lifting, do not offer much benefit. Other studies have readily demonstrated that weight lifting, with its subsequent increase in muscle mass and therefore, resultant rise in basal metabolic rate, can result in increased weight loss and improvement in lipid, cholesterol body chemistry and insulin responsiveness.
A "metabolic equivalent" 1 is equivalent to a metabolic rate consuming 3.5 milliliters of oxygen per kilogram of body weight per minute, or, to a metabolic rate consuming 1 kilocalorie per kilogram of body weight per hour. For example, you are at 2 MET's when walking at 2 MPH, 4 METs when walking at 5 MPH, 8 to 10 METS when jogging at a fair pace or doing calisthenics, and up to 12 METs when engaging in fast jogging, and other very strenuous fast paced exercises. By convention, 1 MET is used at rest. A MET minute would be the MET multiplied by the amount of minutes that exercise was endured; 500 MET minutes can be obtained by performing fast walking for one hundred minutes, or jogging at 10 METs for fifty minutes. These numbers are an approximate, and tend to be based on a 70 kg man. Of course, there will be variation; so use this as a guideline and not as an absolute.
PA stands for "physical activity".
Guidelines regarding weight control are needed because more than 66% of the adult population has overweight or obesity, which is associated with a variety of chronic diseases. Although guidelines of the National Heart, Lung, and Blood Institute recommend a 10% reduction in weight for those who are obese, much evidence supports a lowered health risk with 3% to 5% weight loss.
To prevent weight gain, to lose weight, and to prevent weight regain after weight loss, PA is recommended as a component of weight management. Light-intensity activity is defined as 1.1 to 2.9 metabolic equivalents, moderate-intensity activity as 3.0 to 5.9 metabolic equivalents, and vigorous activity as 6 or more metabolic equivalents.
Although the 2001 ACSM guidelines recommended a minimum of 150 minutes per week of moderate-intensity PA for overweight and obese adults to improve health and 200 to 300 minutes per week for long-term weight loss, the updated guidelines suggest that moderate-intensity PA between 150 and 250 minutes per week is effective to prevent weight gain but will provide only modest weight loss.
Clinically significant weight loss has been reported with greater amounts of PA (> 250 minutes per week). In studies that use moderate but not severe diet restriction, weight loss was improved by moderate-intensity PA between 150 and 250 minutes per week. After weight loss, weight maintenance is improved with PA of more than 250 minutes per week, according to findings of cross-sectional and prospective studies, but there have been no well-designed, randomized controlled trials to determine whether PA is effective to prevent weight regain after weight loss.
Although resistance training does not increase weight loss, it may increase fat-free mass and loss of fat mass while lowering health risk. Available data suggest that endurance PA or resistance training reduces health risk even without weight loss. Evidence to date is insufficient to determine whether PA prevents or ameliorates harmful changes in the risk for chronic disease during periods of weight gain.
Few studies to date have enrolled adults older than 65 years, but this is an important population to evaluate because of concerns that weight loss in older adults may cause loss of fat-free mass and potential bone loss. The position stand reviews the available evidence as it applies to the general population, while pointing out that individuals vary in their response to PA for prevention of weight gain, for weight loss, and for weight maintenance.
Although the review did not include studies of individuals with comorbid conditions that acutely affect weight, such as AIDS and type 1 diabetes, or pharmacotherapy trials, it did include trials enrolling individuals using medication for comorbid diseases, such as hypertension, cardiovascular disease, and type 2 diabetes.
Specific clinical recommendations, and their accompanying level of evidence rating, are as follows:
* For prevention of weight gain in most adults, PA of 150 to 250 minutes per week, with an energy equivalent of 1200 to 2000 kcal/week, will prevent weight gain of more than 3%
* There is a dose-response effect of PA on weight loss, with PA of less than 150 minutes per week resulting in minimal weight loss, PA of more than 150 minutes per week in modest weight loss of approximately 2 to 3 kg, and PA of more than 225 to 420 minutes per week leading to weight loss of 5 to 7.5 kg.
* To maintain weight after weight loss, some studies suggest that PA of approximately 200 to 300 minutes per week will help minimize weight regain, although "more is better." To date, no well-designed, sufficiently powered, energy-balance studies provide evidence concerning the amount of PA needed to prevent weight regain after weight loss.
* Lifestyle PA, which is an ambiguous term that should be better defined to assess available evidence in the literature, may help counteract the small energy imbalance ultimately leading to obesity in most adults.
* If diet restriction is modest but not if diet restriction is severe, PA will increase weight loss.
* Resistance training is ineffective for weight loss with or without diet restriction, according to limited research evidence. However, some limited data suggest that resistance training enhances gain or maintenance of lean mass and loss of body fat during energy restriction. Furthermore, resistance training may also ameliorate risk factors for chronic disease, such as low high-density lipoprotein cholesterol levels, high low-density lipoprotein cholesterol levels, insulin sensitivity, and blood pressure.
"On the basis of the available scientific literature, the ACSM recommends that adults participate in at least 150 min/wk of moderate-intensity PA to prevent significant weight gain and reduce associated chronic disease risk factors," the guidelines authors write. "It is recommended that overweight and obese individuals participate in this level of PA to elicit modest reductions in body weight. However, there is likely a dose effect of PA, with greater weight loss and enhanced prevention of weight regained with doses of PA that approximate 250 to 300 min/wk (approximately 2000 kcal/wk) of moderate intensity PA."
Medscape
To prevent weight gain, to lose weight, and to prevent weight regain after weight loss, PA is recommended as a component of weight management. Light-intensity activity is defined as 1.1 to 2.9 metabolic equivalents, moderate-intensity activity as 3.0 to 5.9 metabolic equivalents, and vigorous activity as 6 or more metabolic equivalents.
Although the 2001 ACSM guidelines recommended a minimum of 150 minutes per week of moderate-intensity PA for overweight and obese adults to improve health and 200 to 300 minutes per week for long-term weight loss, the updated guidelines suggest that moderate-intensity PA between 150 and 250 minutes per week is effective to prevent weight gain but will provide only modest weight loss.
Clinically significant weight loss has been reported with greater amounts of PA (> 250 minutes per week). In studies that use moderate but not severe diet restriction, weight loss was improved by moderate-intensity PA between 150 and 250 minutes per week. After weight loss, weight maintenance is improved with PA of more than 250 minutes per week, according to findings of cross-sectional and prospective studies, but there have been no well-designed, randomized controlled trials to determine whether PA is effective to prevent weight regain after weight loss.
Although resistance training does not increase weight loss, it may increase fat-free mass and loss of fat mass while lowering health risk. Available data suggest that endurance PA or resistance training reduces health risk even without weight loss. Evidence to date is insufficient to determine whether PA prevents or ameliorates harmful changes in the risk for chronic disease during periods of weight gain.
Few studies to date have enrolled adults older than 65 years, but this is an important population to evaluate because of concerns that weight loss in older adults may cause loss of fat-free mass and potential bone loss. The position stand reviews the available evidence as it applies to the general population, while pointing out that individuals vary in their response to PA for prevention of weight gain, for weight loss, and for weight maintenance.
Although the review did not include studies of individuals with comorbid conditions that acutely affect weight, such as AIDS and type 1 diabetes, or pharmacotherapy trials, it did include trials enrolling individuals using medication for comorbid diseases, such as hypertension, cardiovascular disease, and type 2 diabetes.
Specific clinical recommendations, and their accompanying level of evidence rating, are as follows:
* For prevention of weight gain in most adults, PA of 150 to 250 minutes per week, with an energy equivalent of 1200 to 2000 kcal/week, will prevent weight gain of more than 3%
* There is a dose-response effect of PA on weight loss, with PA of less than 150 minutes per week resulting in minimal weight loss, PA of more than 150 minutes per week in modest weight loss of approximately 2 to 3 kg, and PA of more than 225 to 420 minutes per week leading to weight loss of 5 to 7.5 kg.
* To maintain weight after weight loss, some studies suggest that PA of approximately 200 to 300 minutes per week will help minimize weight regain, although "more is better." To date, no well-designed, sufficiently powered, energy-balance studies provide evidence concerning the amount of PA needed to prevent weight regain after weight loss.
* Lifestyle PA, which is an ambiguous term that should be better defined to assess available evidence in the literature, may help counteract the small energy imbalance ultimately leading to obesity in most adults.
* If diet restriction is modest but not if diet restriction is severe, PA will increase weight loss.
* Resistance training is ineffective for weight loss with or without diet restriction, according to limited research evidence. However, some limited data suggest that resistance training enhances gain or maintenance of lean mass and loss of body fat during energy restriction. Furthermore, resistance training may also ameliorate risk factors for chronic disease, such as low high-density lipoprotein cholesterol levels, high low-density lipoprotein cholesterol levels, insulin sensitivity, and blood pressure.
"On the basis of the available scientific literature, the ACSM recommends that adults participate in at least 150 min/wk of moderate-intensity PA to prevent significant weight gain and reduce associated chronic disease risk factors," the guidelines authors write. "It is recommended that overweight and obese individuals participate in this level of PA to elicit modest reductions in body weight. However, there is likely a dose effect of PA, with greater weight loss and enhanced prevention of weight regained with doses of PA that approximate 250 to 300 min/wk (approximately 2000 kcal/wk) of moderate intensity PA."
Medscape
Also note that these guidelines suggest that resistance exercises, such as weight lifting, do not offer much benefit. Other studies have readily demonstrated that weight lifting, with its subsequent increase in muscle mass and therefore, resultant rise in basal metabolic rate, can result in increased weight loss and improvement in lipid, cholesterol body chemistry and insulin responsiveness.
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