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Background: Dissemination of the Physical Activity Guidelines for Americans (Guidelines) is needed, but how individuals respond to the Guidelines is not well understood. This surveillance study describes US adults’ reported responses to and information sources for hearing about the Guidelines and explores relationships between how respondents heard about the Guidelines and their reported response(s). Methods: Data were analyzed from the population-based 2019 Health Information National Trends Survey 5 Cycle 3. Population-weighted proportions of response were calculated. Among those who had heard about the Guidelines, binary logistic regressions examined associations between the reported response(s) and the information source and number of sources reported. Results: The analytical sample included 5047 adults. Nearly 65% of US adults reported hearing about the Guidelines, and 29% reported a behavioral response (eg, increased physical activity). Hearing about the Guidelines through health professionals (adjusted odds ratio = 2.30, 95% confidence interval, 1.45–3.65) or social media (adjusted odds ratio = 1.89, 95% confidence interval, 1.20–2.96) (vs other sources) was associated with reporting increasing physical activity. Hearing from multiple sources (vs one source) was associated with reporting increasing physical activity (adjusted odds ratio = 1.97, 95% confidence interval, 1.18–3.31). Conclusion: Findings suggest dissemination of the Guidelines across multiple channels may promote greater changes in physical activity.

In 2019, the National Youth Sports Strategy was released and called for regular analysis, interpretation, and dissemination of U.S. youth sports surveillance data. The purpose of this study is to provide the recent national estimates of U.S. youth aged 6-17 years who participate in sports and examine the differences in participation by demographic characteristics, overall and across age groups.Nationally representative data on parent-reported youth sports participation from the 2017-2018 National Survey of Children's Health (n=36,779) were analyzed in 2019. The prevalence and 95% CIs of youth sports participation were estimated by demographic characteristics, overall and by age group. Investigators assessed the significant (p0.05) differences and trends in participation using pairwise t-tests and orthogonal polynomial contrasts and effect modification by age group using logistic regression models.Overall, 57.7% (95% CI=56.6, 58.9) of U.S. youth participated in sports. Participation was highest among youth who were aged 10-13 years, male, and white, non-Hispanic and increased with increasing parent/caregiver education and household income (all p0.05). Differences in participation by demographic characteristics were more pronounced among younger youth. For example, prevalence by household income level ranged from 32.7% to 79.9% among children aged 6-9 years and from 41.6% to 67.2% among youth aged 14-17 years.Although nearly 6 in 10 U.S. youth participate in sports, substantial disparities exist, especially among younger children. Identifying and overcoming the barriers may help increase youth sports participation in the U.S.

Background: The Move Your Way campaign, developed by the Office of Disease Prevention and Health Promotion, aims to improve Americans’ adherence to the Physical Activity Guidelines for Americans. This article describes the research that informed the campaign’s products, messaging, and strategy. Methods: A mixed-methods approach was used to understand participants’ preferences for physical activity messages and information seeking. Two rounds (round 1 [n = 95] and round 2 [n = 73]) of focus groups and an online survey (n = 2050) were conducted with adult physical activity contemplators. A third round (n = 84) of focus groups was conducted with children, teens, and parents of young children. Results: Adults, parents, teens, and children preferred messages that reflected diverse examples of activities; most participants disliked “one-size-fits-all” recommendations. Adults and parents preferred messages that emphasized specific health benefits over generic messages about overall health. Although some participants preferred getting physical activity information from digital search tools and social media platforms, many preferred getting this information from family members and friends. Conclusion: The Office of Disease Prevention and Health Promotion translated these findings into 3 themes used for Move Your Way implementation: (1) leverage social and community connections, (2) emphasize representation through inclusion and diversity, and (3) customize physical activity recommendations to make them more achievable.

Background: The Office of Disease Prevention and Health Promotion completed research to understand factors that could encourage Americans to follow the Physical Activity Guidelines for Americans, second edition, released in 2018. This study describes survey research assessing demographic characteristics that might be related to knowledge and awareness of the guidelines. Methods: An online survey of 2050 adult physical activity contemplators assessed knowledge of physical activity, awareness of the guidelines, and knowledge of dosage recommendations. Univariate and bivariate analyses were performed, and demographic differences in knowledge and awareness were analyzed using Pearson chi-square tests and Fisher exact tests. Results: Respondents had medium to high knowledge of physical activity, although knowledge varied significantly by socioeconomic factors. Knowledge of dosage recommendations was very low, with 2% and 3% of respondents correctly identifying recommended moderate- and vigorous-intensity doses, respectively. Only 22% were aware of the guidelines; awareness was greater among those with a higher education or income and those without a disability. Conclusions: These findings guided the development of the Office of Disease Prevention and Health Promotion’s Move Your Way campaign and reinforced the need to raise awareness of the guidelines and promote behavior change among physical activity contemplators—particularly those from lower socioeconomic groups.

This cohort study uses national data to explore the dose-response association between guideline-recommended physical activity and mortality in older adults.

PURPOSE: To summarize the evidence from the 2018 Physical Activity Guidelines Advisory Committee Scientific Report, including new evidence from an updated search of the effects of physical activity on maternal health during pregnancy and postpartum. METHODS: An initial search was undertaken to identify systematic reviews and meta-analyses published between 2006 and 2016. An updated search then identified additional systematic reviews and meta-analyses published between January 2017 through February 2018. The searches were conducted in PubMed®, CINAHL, and Cochrane Library and supplemented through hand-searches of reference lists of included articles and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: The original and updated searches yielded a total of 76 systematic reviews and meta-analyses. Strong evidence demonstrated that moderate-intensity physical activity reduced the risk of excessive gestational weight gain, gestational diabetes, and symptoms of postpartum depression. Limited evidence suggested an inverse relationship between physical activity and risk of preeclampsia, gestational hypertension, and antenatal anxiety and depressive symptomology. Insufficient evidence was available to determine the impact of physical activity on postpartum weight loss, postpartum anxiety, and affect during both pregnancy and postpartum. For all health outcomes, there was insufficient evidence to determine whether the relationships varied by age, race/ethnicity, socioeconomic status, or pre-pregnancy weight status. CONCLUSIONS: The gestational period is an opportunity to promote positive health behaviors that can have both short- and long-term benefits for the mother. Given the low prevalence of physical activity in young women in general, and the high prevalence of obesity and cardiometabolic diseases among the U.S. population, the public health importance of increasing physical activity in women of child-bearing age, before, during, and following pregnancy is substantial.

PURPOSE. Conduct a systematic umbrella review to evaluate the relationship of physical activity (PA) with all-cause mortality, cardiovascular mortality, and incident cardiovascular disease; to evaluate the shape of the dose-response relationships; and to evaluate these relationships relative to the 2008 Physical Activity Guidelines Advisory Committee (PAGAC) Report. METHODS. Primary search encompassing 2006 – March, 2018 for existing systematic reviews, meta-analyses, and pooled analyses reporting on these relationships. Graded the strength of evidence using a matrix developed for the PAGAC. RESULTS. The association of self-reported moderate-to-vigorous physical activity (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality, and atherosclerotic cardiovascular diseases — including incident coronary heart disease, ischemic stroke and heart failure — are very similar. Increasing MVPA to Guidelines amounts in the inactive U.S. population has the potential to have an important and substantial positive impact on these outcomes in the adult population. The following points are clear: the associations of PA with beneficial health outcomes begin when adopting very modest (one-third of Guidelines) amounts; any MVPA is better than none; meeting the 2008 PA guidelines reduces mortality and CVD risk to about 75 percent of the maximal benefit obtained by physical activity alone; PA amounts beyond Guidelines recommendations amount reduces risk even more, but greater amounts of PA are required to obtain smaller health benefits; and there is no evidence of excess risk over the maximal effect observed at about three to five times the amounts associated with current guidelines. When PA is quantified in terms of energy expenditure (MET-hours per week), these relationships hold for walking, running, and biking. CONCLUSIONS. To avoid the risks associated with premature mortality and the development of ischemic heart disease, ischemic stroke, and all-cause heart failure, all adults should strive to reach the 2008 Physical Activity Guidelines for Americans.

PURPOSE. Systematic primary literature review to evaluate the relationship of physical activity —as measured by daily step counts — with all-cause mortality, cardiovascular disease mortality, incident cardiovascular disease, and type 2 diabetes mellitus; to evaluate the shape of dose-response relationships; and to interpret findings in the context of development of the Physical Activity Guidelines for Americans 2(nd) Edition. METHODS. Primary literature search encompassing 2011 – March, 2018 for existing literature reporting on these relationships. RESULTS. Eleven pertinent articles were identified. Seven longitudinal studies examined the relationship between daily step counts and mortality, disease incidence or risk. Two studies examined objectively measured steps per day and all-cause mortality, one was restricted to a relatively small elderly population. One study examined cardiovascular events, defined as cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. The other four longitudinal studies addressed incident type 2 diabetes. All longitudinal studies reported an inverse relationship between steps per day and outcome risk. In one study, 531 cardiovascular events occurred during more than 45,000 person-years of follow-up. Before intervention, each 2,000 steps per day increment up to 10,000 steps was associated with a 10-percent lower cardiovascular event rate. Also, for every 2,000 steps per day increase over baseline, there was an 8-percent yearly reduction in cardiovascular event rate in individuals with impaired glucose tolerance. CONCLUSIONS. Daily step count is a readily accessible means by which to monitor and set physical activity goals. Recent evidence supports previously limited evidence of an inverse dose-response relationship of daily steps with important health outcomes, including all-cause mortality, cardiovascular events, and type 2 diabetes. However, more independent studies will be required before these observations can be translated into public health guidelines.

PurposeThis systematic umbrella review examines and updates the evidence on the relationship between physical activity (PA) and blood pressure (BP) presented in the 2008 Physical Activity Guidelines Advisory Committee Scientific Report.MethodsWe performed a systematic review to identify syst

Purpose To review and update the evidence of the relationship between physical activity, risk of fall-related injury, and physical function in community-dwelling older people that was presented in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (PAGAC Report). Methods Duplicate independent screenings of 1415 systematic reviews and meta-analyses published between 2006 and 2016 identified from PubMed®, Cochrane Library, and CINAHL databases yielded 111 articles used for the PAGAC Report. The PAGAC Aging Subcommittee members graded scientific evidence strength based upon a five-criteria rubric and assigned one of four grades: strong, moderate, limited, or not assignable. An updated search of 368 articles published between January 2017 and March 2018 yielded 35 additional pertinent articles. Results Strong evidence demonstrated that physical activity reduced the risk of fall-related injuries by 32% to 40%, including severe falls requiring medical care or hospitalization. Strong evidence also supported that physical activity improved physical function and reduced the risk of age-related loss of physical function in an inverse graded manner among the general aging population, and improved physical function in older people with frailty and with Parkinson's disease. Aerobic, muscle-strengthening, and/or multicomponent physical activity programs elicited the largest improvements in physical function in these same populations. Moderate evidence indicated that for older adults who sustained a hip fracture or stroke, extended exercise programs and mobility-oriented physical activity improved physical function. Conclusions Regular physical activity effectively helps older adults improve or delay the loss of physical function and mobility while reducing the risk of fall-related injuries. These important public health benefits underscore the importance of physical activity among older adults, especially those living with declining physical function and chronic health conditions.

This cross-sectional study examines the current status and secular trends in physical activity and sedentary behavior among US adults using data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016., Key Points Question What are the concurrent changing trends in adherence to the Physical Activity Guidelines for Americans for aerobic activity and time spent on sedentary behavior among US adults during the past decade? Findings In a series of cross-sectional studies including data from 27 343 participants 18 years or older from the US National Health and Nutrition Examination Surveys for 2007 to 2016, the adherence rate to the Physical Activity Guidelines for Americans for aerobic activity was not significantly improved from 2007-2008 (63.2%) to 2015-2016 (65.2%). However, time spent on sedentary behavior increased from 5.7 hours per day in 2007-2008 to 6.4 hours per day in 2015-2016. Meaning The findings suggest that further nationwide efforts are warranted to promote physical activity and reduce sedentary time in the United States., Importance The updated 2018 Physical Activity Guidelines for Americans (PAG) reaffirmed key recommendations regarding aerobic activity in the 2008 edition and recently introduced health risks of sedentary behaviors and their association with physical activity. Objective To examine the concurrent changing trends in adherence to the PAG for aerobic activity and time spent on sedentary behavior in US adults from 2007 to 2016. Design, Setting, and Participants This study used data from a series of cross-sectional, nationally representative surveys on adults 18 years or older from the National Health and Nutrition Examination Surveys from 2007 to 2016. Data analysis was performed from September 1, 2018, to March 31, 2019. Main Outcomes and Measures Duration, frequency, and intensity of leisure-time, work-related, and transportation-related aerobic activity were ascertained by a standardized questionnaire and summed as minutes per week. Adherence to the PAG for aerobic activity was defined as engaging in at least 150 minutes a week of moderate-intensity or 75 minutes a week of vigorous-intensity aerobic physical activity or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity. Time spent on sedentary behavior was estimated by hours spent sitting on a typical day. Results Among 27 343 participants 18 years or older (13 630 [52.0%] female; 14 628 [66.6%] non-Hispanic white), the weighted adherence rate to the PAG for aerobic activity was 65.2% (95% CI, 62.3%-68.2%) in 2015-2016, with no significant change from 2007-2008 (63.2%; 95% CI, 60.2%-66.1%) to 2015-2016 (P = .15 for trend). Time spent on sedentary behavior significantly increased over time from a weighted mean (SE) of 5.7 (0.3) hours per day in 2007-2008 to 6.4 (0.2) hours per day in 2015-2016 (P 6 hours per day) increased from 16.1% (95% CI, 14.4%-17.8%) in 2007-2008 to 18.8% (95% CI, 17.7%-20.0%) in 2015-2016. Conclusions and Relevance The findings suggest that the adherence rate to the PAG for aerobic activity in US adults has not improved since the release of the first edition in 2008 but that time spent on sedentary behavior has significantly increased over time. Further nationwide efforts appear to be warranted to not only promote physical activity but also reduce sedentary time in the United States.

INTRODUCTION. We conducted a systematic umbrella review to evaluate the literature relating to effects of physical activity on pain, physical function, health-related quality of life (HRQoL), co-morbid conditions and osteoarthritis (OA) structural disease progression in individuals with lower extremity OA. METHODS. Our primary search encompassed 2011 – 2/2018 for existing systematic reviews (SRs), meta-analyses (MAs) and pooled analyses dealing with physical activity including exercise (not mixed with any other intervention and compared to a no-activity control group). A supplementary search encompassed 2006-2/2018 for original research related to physical activity (including exercise) and lower limb OA progression. Study characteristics were abstracted and risk of bias was assessed. RESULTS. Physical activity decreased pain and improved physical function (strong evidence) and improved HRQoL (moderate evidence) among people with hip or knee OA relative to less active adults with OA. There was no evidence to suggest accelerated OA progression for physical activity below 10,000 steps per day. Both physical activity equivalent to the 2008 Physical Activity Guidelines for Americans (150 minutes/week of moderate-intensity exercise in bouts ≥10 minutes) and lower levels of physical activity (at least 45 total minutes/week of moderate-intensity) were associated with improved or sustained high function. No SRs/MAs addressing co-morbid conditions in OA were found. Measurable benefits of physical activity appeared to persist for periods of up to 6 months following cessation of a defined program. CONCLUSIONS. People with lower extremity OA should be encouraged to engage in achievable amounts of physical activity, of even modest intensities. They can choose to accrue minutes of physical activity throughout the entire day, irrespective of bout duration, and be confident in gaining some health and arthritis-related benefits.

PURPOSE. To conduct a systematic literature review to determine if physical activity is associated with prevention of weight gain in adults. METHODS. The primary literature search was conducted for the 2018 Physical Activity Guidelines Advisory Committee and encompassed literature through June 2017, with an additional literature search conducted to include literature published through March 2018 for inclusion in this systematic review. RESULTS. The literature review identified 40 articles pertinent to the research question. There is strong evidence of an association between physical activity and prevention of weight gain in adults, with the majority of the evidence from prospective cohort studies. Based on limited evidence in adults, however, there is a dose-response relationship and the prevention of weight gain is most pronounced when moderate-to-vigorous intensity physical activity (≥3 METS) is above 150 minutes per week. While there is strong evidence to demonstrate that the relationship between greater time spent in physical activity and attenuated weight gain in adults is observed with moderate-to-vigorous intensity physical activity, there is insufficient evidence available to determine if there is an association between light-intensity activity (

PURPOSE: To provide an overview of relationships between sedentary behavior and mortality as well as incidence of several non-communicable diseases and weight status reported in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (2018 PAGAC Scientific Report), and to update the evidence from recent studies. METHODS: Evidence related to sedentary behavior in the 2018 PAGAC Scientific Report was summarized and a systematic review was undertaken to identify original studies published between January 2017 and February 2018. RESULTS: The 2018 PAGAC Scientific Report concluded there was strong evidence that high amounts of sedentary behavior increase the risk for all-cause and cardiovascular disease (CVD) mortality and incident CVD and type 2 diabetes. Moderate evidence indicated sedentary behavior is associated with incident endometrial, colon and lung cancer. Limited evidence suggested sedentary behavior is associated with cancer mortality and weight status. There was strong evidence that the hazardous effects of sedentary behavior are more pronounced in physically inactive people. Evidence was insufficient to determine if bout length or breaks in sedentary behavior are associated with health outcomes. The new literature search yielded seven new studies for all-cause mortality, two for CVD mortality, two for cancer mortality, four for type 2 diabetes, one for weight status, and four for cancer; no new studies were identified for CVD incidence. Results of the new studies supported the conclusions in the 2018 PAGAC Scientific Report. CONCLUSIONS: The results of the updated search add further evidence on the association between sedentary behavior and health. Further research is required on how sex, age, race/ethnicity, socioeconomic status, and weight status may modify associations between sedentary behavior and health outcomes.

PURPOSE: The 2018 Physical Activity Guidelines Advisory Committee systematically searched existing literature reviews to assess the relationship between high-intensity interval training (HIIT) and reduction in cardiometabolic disease risk. METHODS: Duplicate independent screenings of 260 articles identified from PubMed®, Cochrane Library, and CINAHL databases yielded suitable data from one systematic review and two meta-analyses. Search terms included a combination of “High intensity” “Physical activity/exercise”, and “Interval training” and outcome-specific terms. Quality of the included reviews was assessed using a tailored version of the AMSTARExBP report on quality. Exposure Subcommittee members graded scientific evidence strength based upon a 5-criteria rubric and assigned one of four grades: strong, moderate, limited, or not assignable. RESULTS: Moderate evidence indicates that HIIT can improve insulin sensitivity, blood pressure, and body composition in adults with group mean ages ranging from ~20 to ~77 years. These HIIT-induced improvements in cardiometabolic disease risk factors are comparable to those resulting from moderate-intensity continuous training; and they are more likely to occur in adults at higher risk of cardiovascular disease and diabetes than in healthy adults. Moderate evidence also indicates that adults with overweight or obesity classification are more responsive than adults with normal weight to HIIT-related improvements in insulin sensitivity, blood pressure, and body composition. Insufficient evidence was available to determine whether a dose-response relationship exists between the quantity of HIIT performed and several risk factors for cardiovascular disease and diabetes; or whether the effects of HIIT on cardiometabolic risk factors are influenced by age, sex, race/ethnicity, or socioeconomic status. CONCLUSIONS: High-intensity interval training by adults, especially those with overweight and obesity classification, can improve insulin sensitivity, blood pressure, and body composition, comparable to those resulting from moderate-intensity continuous training.

PURPOSE. To conduct a systematic literature review to determine if physical activity episodes of

Importance Approximately 80% of US adults and adolescents are insufficiently active. Physical activity fosters normal growth and development and can make people feel, function, and sleep better and reduce risk of many chronic diseases. Objective To summarize key guidelines in thePhysical Activity Guidelines for Americans, 2nd edition (PAG). Process and Evidence Synthesis The 2018 Physical Activity Guidelines Advisory Committee conducted a systematic review of the science supporting physical activity and health. The committee addressed 38 questions and 104 subquestions and graded the evidence based on consistency and quality of the research. Evidence graded as strong or moderate was the basis of the key guidelines. The Department of Health and Human Services (HHS) based the PAG on the2018 Physical Activity Guidelines Advisory Committee Scientific Report. Recommendations The PAG provides information and guidance on the types and amounts of physical activity to improve a variety of health outcomes for multiple population groups. Preschool-aged children (3 through 5 years) should be physically active throughout the day to enhance growth and development. Children and adolescents aged 6 through 17 years should do 60 minutes or more of moderate-to-vigorous physical activity daily. Adults should do at least 150 minutes to 300 minutes a week of moderate-intensity, or 75 minutes to 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. They should also do muscle-strengthening activities on 2 or more days a week. Older adults should do multicomponent physical activity that includes balance training as well as aerobic and muscle-strengthening activities. Pregnant and postpartum women should do at least 150 minutes of moderate-intensity aerobic activity a week. Adults with chronic conditions or disabilities, who are able, should follow the key guidelines for adults and do both aerobic and muscle-strengthening activities. Recommendations emphasize that moving more and sitting less will benefit nearly everyone. Individuals performing the least physical activity benefit most by even modest increases in moderate-to-vigorous physical activity. Additional benefits occur with more physical activity. Both aerobic and muscle-strengthening physical activity are beneficial. Conclusions and Relevance ThePhysical Activity Guidelines for Americans, 2nd edition, provides information and guidance on the types and amounts of physical activity that provide substantial health benefits. Health professionals and policy makers should facilitate awareness of the guidelines and promote the health benefits of physical activity and support efforts to implement programs, practices, and policies to facilitate increased physical activity and to improve the health of the US population.

Introduction: In 2016, the 2018 Physical Activity Guidelines Advisory Committee, a group of experts in exercise science and health, began an extensive review of the literature to inform the second edition of the Physical Activity Guidelines for Americans. Methods: The purpose of this paper is to describe the evidence-based methodology used to review, evaluate, and synthesize published, peer-reviewed physical activity research. The protocol-driven methodology was designed to maximize transparency, minimize bias, and ensure relevant, timely, and high-quality systematic reviews. Training protocols, quality control procedures, search strategies, assessment instruments, abstraction guides and forms, and reporting templates were developed. Results: A systematic approach was used to select the evidence for the 2018 Physical Activity Guidelines Advisory Committee Scientific Report that included umbrella reviews and systematic reviews. Within 16 months, 38 searches were conducted; and 20,838 titles, 4913 abstracts, and 2139 full texts were triaged. Of those, 1130 articles were abstracted to answer 38 research questions. Conclusions: To inform population-based physical activity guidelines, this systematic process facilitated a vast review of the literature on physical activity and health in a short period of time. This flexible, yet rigorous and transparent process included a clear and detailed methodology with a focus on training and quality control.

Despite the well-known benefits of youths engaging in 60 or more minutes of daily physical activity, physical inactivity remains a significant public health concern. The 2008 Physical Activity Guidelines for Americans (PAG) provides recommendations on the amount of physical activity needed for overall health; the PAG Midcourse Report (2013) describes effective strategies to help youths meet these recommendations. Public health professionals can be dynamic change agents where youths live, learn, and play by changing environments and policies to empower youths to develop regular physical activity habits to maintain throughout life. We have summarized key findings from the PAG Midcourse Report and outlined actions that public health professionals can take to ensure that all youths regularly engage in health-enhancing physical activity.

The development of the U.S. dietary policy utilizes an evolving process that now provides a rigorous, evidence based approach for developing the Dietary Guidelines for Americans (DGA). Objective To...

In the United States, high rates of obesity and chronic disease impose serious consequences on the population’s health and health care system. Primary care providers are critical to broad prevention efforts aiming to reduce the burden of chronic disease in the nation and play an important role in addressing lifestyle behaviors that can result in illness and premature death. Unhealthy dietary behaviors largely contribute to morbidity and mortality in the United States despite national efforts to improve the nutritional quality of the typical American diet. This article discusses a comprehensive set of national evidence-based recommendations known as the Dietary Guidelines for Americans that can support primary care providers’ efforts to improve patient outcomes through optimal nutrition and healthy lifestyle behaviors. This article also describes basic behavioral counseling techniques primary care providers can incorporate into time-limited patient encounters to help improve the dietary and physical activity behaviors of their patients.