• Fitness & Health
• Sport & Exercise Science
• Physical Education
• Strength & Conditioning
• Sports Medicine
• Sport Management
• Dance

Physical activity guidelines for a healthy weight

This is an excerpt from Foundations of Physical Activity and Public Health 2nd Edition With Web Resource by Harold Kohl III,Tinker Murray & Deborah Salvo.

For many adults, obesity is associated with significant increases in abdominal fat that increase the risk for metabolic syndrome and type 2 diabetes (see chapter 5). Regular participation in aerobic physical activity and exercise can decrease total body fat and abdominal fat, and these changes are consistent with improved metabolic function. Generally, the greater the volume of physical activity or exercise acquired by individuals or populations, the greater the reductions in body and abdominal fat.

For children and adolescents, the prevention of excessive weight gain during maturation is critical to prevent obesity and overweight in adulthood. Unfortunately, recent public health surveys note that the parents of many at-risk children are not aware of the problem or do not recognize that their children are overweight. Recent U.S. national policy statements targeting pediatricians and other health care providers assert that children and adolescents who are overweight or obese in their early teens should be identified as early as possible and given some sort of weight management plan through the intervention of parents, teachers, coaches, and family physicians.

One of the most obvious influences on weight management is how people perceive their ideal weight or physique. Research findings indicate a great disparity between reasonable weight loss or weight gain goals and people's “dream weight.” Even though some people may not reach their goal weight, they will likely report positive physical, social, and psychological benefits from any weight loss. The following scientific evidence and guidelines can help individuals and populations establish realistic goals for weight management (e.g., achieving a healthy weight) and meet their specific needs (e.g., weight loss, weight stability, prevention of weight regain, or loss of excessive abdominal fat) through regular participation in physical activity and exercise.

Scientific Evidence

The 2008 PAGAC noted physical activity (150 minutes per week to ≥300 minutes per week) was associated with modest weight loss, prevention of weight gain following weight loss, and reductions in total and regional adiposity. Evidence that resistance training helped with weight maintenance was not as strong, given that resistance training increases lean muscle mass, and the volume of resistance training regimes was usually less than that for aerobic training.

The 2018 PAGAC expanded the review of the evidence available in 2008, and focused on weight maintenance and weight gain within normal BMI limits (18.5 to < 25 kg/m²) for adults in relation to participating in 150 minutes per week or more of physical activity. The 2018 report also reviewed the impact of sedentary behavior and sedentary activity in relationship to physical activity and weight status. The specific 2018 PAGAC findings regarding weight gain were:

• Strong evidence demonstrates that the significant relationship between greater time spent in physical activity (≥300 minutes per week) and attenuated weight gain in adults is observed with moderate-to-vigorous physical activity.
• Moderate evidence indicates that the relationship between greater amounts of physical activity and attenuated weight gain in adults does not appear to vary by sex.
• Limited evidence suggests a dose-response relationship between physical activity and the risk of weight gain in adults, with greater amounts of physical activity (150 minutes per week) associated with lower risk of weight gain.
• Limited evidence suggests that the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by age, with the effect diminishing with increasing age. The evidence from studies of older adults, however, is inconsistent.
• Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by race and ethnicity.
• Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by socioeconomic status.
• Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by initial weight status.
• Insufficient evidence is available to determine an association between light-intensity activity and attenuated weight gain in adults.

The 2018 PAGAC concluded the following with regard to the impact of sedentary behavior and sedentary activity for adults in relationship to physical activity and weight status:

• Limited evidence suggests a positive relationship between greater time spent in sedentary behavior and higher levels of adiposity and indicators of weight status.
• Limited evidence suggests the existence of a direct, graded dose-response relationship between greater sedentary behavior and higher levels of adiposity and indicators of weight status.
• Insufficient evidence is available to determine whether the relationship between sedentary behavior and weight status varies by age, sex, ethnicity, socioeconomic status, or baseline weight status.
• Insufficient evidence is available to determine whether the relationship between sedentary behavior and weight status varies by amount of moderate-to-vigorous physical activity.
• Insufficient evidence is available to determine whether bouts or breaks in sedentary behavior are important factors in the relationship between sedentary behavior and weight status.

As mentioned earlier in the chapter, regular physical activity and exercise are also important to prevent and control obesity and overweight in children and adolescents. The 2008 PAGAC found strong evidence demonstrating that higher levels of physical activity were associated with multiple beneficial health outcomes, including cardiorespiratory and muscular fitness, bone health, and maintenance of healthy weight status in children and adolescents (ages 6-19). The 2018 PAGAC focused on expanding the review of literature since 2008 with the addition of studies on children 3-6 years of age. The additional scientific recommendations of the 2018 PAGAC for youth were as follows:

• Strong evidence demonstrates that higher amounts of physical activity are associated with a reduced risk of excessive increases in body weight and adiposity in children ages 3 to 6 years.
• Limited evidence suggests that greater time spent in sedentary behavior is related to higher weight status or adiposity in children and adolescents; the evidence is somewhat stronger for television viewing or screen time than for total sedentary time.
• Insufficient evidence is available to determine whether the relationship between physical activity and health effects in children younger than 6 years of age is moderated by age, sex, race, ethnicity, weight status, or socioeconomic status.

More Excerpts From Foundations of Physical Activity and Public Health 2nd Edition With Web Resource

---