Evolution, body composition, insulin receptor competition, and insulin resistance.

OBJECTIVE: Better understanding of the relationships between body composition and insulin resistance. RESULTS: Average human adiposity and sarcopenia have attained unprecedented levels and the resultantly abnormal body composition distorts insulin receptor balance. Compared to evolutionary norms we now have too many adipocyte insulin receptors (in adipose tissue and liver) and too few myocyte insulin receptors. The body's insulin receptors can be conceptualized as competing for insulin molecules released from the pancreas. When an insulin molecule docks on an adipocyte receptor, substantially fewer glucose molecules are cleared from the blood than when an insulin molecule docks on a myocyte insulin receptor. Populational insulin receptor imbalance would seem to parallel the secular rise in insulin resistance and offers an attractive pathophysiological explanation for the accompanying type 2 diabetes epidemic. CONCLUSION: An evolutionary perspective regarding body composition, insulin receptor imbalance, and the consequent impact on carbohydrate metabolism should enhance public acceptance of recommendations to increase physical activity.

Do ethnicity and gender matter when using the theory of planned behavior to understand fruit and vegetable consumption?

A majority of Americans do not meet the recommendation to eat five servings of fruits and vegetables per day (5-A-Day). The purpose of the present study was to examine the utility of the theory of planned behavior (TPB) for understanding 5-A-Day intentions and behavior and to determine whether any of the TPB relationships were moderated by ethnicity or gender. A total of 413 participants completed a baseline TPB questionnaire and a fruit and vegetable consumption measure 2 weeks later. Path analyses showed that affective attitude and perceived behavioral control significantly predicted intention for blacks, whites, males and females (R(2) ranged from .32 to .40), whereas subjective norm was a significant predictor for blacks, males, and females only. Intention significantly predicted 5-A-Day (R(2) ranged from .17 to .22) for all groups. Follow-up invariance analyses showed that the subjective norm/intention relationship was significantly stronger for black compared to white students. Finally, several key beliefs were identified for all four demographic groups. Therefore, the current results suggest that the TPB may be a useful framework to utilize when developing 5-A-Day interventions.

Understanding nonsmoking in African American and Caucasian college students: an application of the theory of planned behavior.

Few studies have considered whether psychological determinants of nonsmoking among college students vary by ethnicity. The authors tested the theory of planned behavior (TPB) to explain differences in nonsmoking intentions of 238 African American and 197 Caucasian college students who completed an in-class TPB questionnaire and a smoking assessment 1 week later. After removing 35 students who reported smoking at the baseline assessment, regressions were used to examine ethnic effects on TPB constructs when predicting nonsmoking intentions. Caucasians had statistically significant higher nonsmoking intentions than African Americans. Further, subjective norms for Caucasians and attitudes for African Americans had small but significant relations to intention, but perceived behavioral control (PBC) was a strongly significant predictor for both ethnic groups. However, the prediction of nonsmoking intentions was not statistically moderated by ethnicity for any of the TPB constructs. This study suggests that the TPB may aid in understanding collegiate nonsmoking intentions and help begin to explain differences in smoking on the basis of ethnicity. Last, because of strong associations shown in this study, PBC should be considered when developing ethnic-specific smoking interventions in college students.

A new evaluation tool to obtain practice-based evidence of worksite health promotion programs.

INTRODUCTION: The Centers for Disease Control and Prevention developed the Swift Worksite Assessment and Translation (SWAT) evaluation method to identify promising practices in worksite health promotion programs. The new method complements research studies and evaluation studies of evidence-based practices that promote healthy weight in working adults. METHODS: We used nationally recognized program evaluation standards of utility, feasibility, accuracy, and propriety as the foundation for our 5-step method: 1) site identification and selection, 2) site visit, 3) post-visit evaluation of promising practices, 4) evaluation capacity building, and 5) translation and dissemination. An independent, outside evaluation team conducted process and summative evaluations of SWAT to determine its efficacy in providing accurate, useful information and its compliance with evaluation standards. RESULTS: The SWAT evaluation approach is feasible in small and medium-sized workplace settings. The independent evaluation team judged SWAT favorably as an evaluation method, noting among its strengths its systematic and detailed procedures and service orientation. Experts in worksite health promotion evaluation concluded that the data obtained by using this evaluation method were sufficient to allow them to make judgments about promising practices. CONCLUSION: SWAT is a useful, business-friendly approach to systematic, yet rapid, evaluation that comports with program evaluation standards. The method provides a new tool to obtain practice-based evidence of worksite health promotion programs that help prevent obesity and, more broadly, may advance public health goals for chronic disease prevention and health promotion.

Promising practices in promotion of healthy weight at small and medium-sized US worksites.

INTRODUCTION: We developed a new evaluation method to identify promising practices for promoting healthy weight among employees at small and medium-sized worksites. METHODS: We used a structured rating and selection process to select 9 worksites with approximately 100 to 3,000 employees from a pool of worksites with health promotion programs reputed to be exemplary. A site visit over 2 sequential half-days at each site included interviews with senior management, program staff, vendors, and wellness committees; observation guided by a written environmental assessment; and structured review of program data on health outcomes of wellness program participants. The team corroborated findings from interviews, observations, and reviews of aggregate data on health outcomes of participants. Using the site visit reports, the project team and a separate panel of experts identified worksite health promotion practices that were promising, innovative, feasible to implement in a variety of settings, sustainable, and relevant for public health. RESULTS: Innovative practices included peer coaching, wellness screening coupled with motivational interviewing and follow-up, free access to fitness facilities, and incentives such as days of paid leave for participation in wellness programs. Introduction of incentives was associated with higher participation rates. To build the business case for their programs, staff at several worksites used aggregate data on decreases in high blood pressure, serum cholesterol concentrations, and body weight in longitudinal samples of program participants. CONCLUSION: The evaluation method identified promising practices implemented at small and medium-sized worksites to promote healthy weight and related favorable health outcomes.

Lost in translation: evidence-based interventions in physical activity and nutrition.

From an ecological perspective, obesity can be understood as an adaptation to a complex modern society.(1) Healthy lifestyle recommendations on how much physical activity to get and what and how much to eat continue to be updated and refined, most recently by the US Department of Health and Human Services and the Department of Agriculture in the Dietary Guidelines for Americans 2005.(2) These new insights and interpretations build on fundamental principles and recommendations that have been in place for many years,(3) yet sedentary behavior and overeating are more pervasive than ever. We see these problems firsthand every day, both as clinicians and as concerned citizens.

Comparison of blood lipids and blood pressure in black and white collegiate male athletes.

Blood lipids, lipoproteins, and blood pressure (BP) were examined in 74 black and 93 white male NCAA Division I-A collegiate football athletes. Subjects were involved in resistance training and anaerobic running and all ate at the same training table. All measurements were done in the morning following a 12 hour fast. No significant differences were found in mean systolic (128 mm Hg) or diastolic (77 mm Hg) BPs. Blacks and whites were similar in age, height, weight, V̇O2max estimated from a 12 minute run test, total serum cholesterol, and low-density lipoprotein cholesterol (LDL-C). However, the black athletes had significantly (P < 0.01) lower serum triglycerides, total cholesterol to HDL-C ratio, and higher high-density lipoprotein cholesterol (HDL-C) compared to whites. In a subgroup of 34 subjects, there were no differences in dietary fat, carbohydrate, cholesterol, sodium, potassium, calcium, or fiber intake. These data suggest a race-related difference in some blood lipids-lipoproteins without a concomitant difference in BP within a group of young adult male athletes.

Energy balance: the key to a unified message on diet and physical activity.

The aim of this commentary is to highlight the advantages of an energy-balance framework to unify diet and physical activity messages. Despite an array of pharmacotherapies, lifestyle modification remains the first-line approach for preventing obesity, cardiometabolic diseases, and cancer. Yet, patients, let alone professionals, often perceive recommendations on diet to be separate from, or even competitive with, those on physical activity. They perceive these as 2 sets of unrelated guidelines. This is a mistaken and unfortunate view. Nutrition and physical activity are highly interrelated, complementary, and synergistic. As exemplified by findings from the National Weight Control Registry, the power of combining a wise diet and a physically active lifestyle is compelling. Accordingly, the American Cancer Society and the American Heart Association have integrated their respective diet/physical activity/body weight recommendations into single documents. Corresponding follow-through at the clinical level is overdue. The diet versus physical activity question is passé. Let us move forward by teaching our patients about energy balance, the inclusive concept that captures the synergy between diet and physical activity. Adopting an energy-balance framework can improve the relevancy and potency of lifestyle messages to patients and better enable them to develop and apply effective behavior-change skills.

Understanding adherence to 5 servings of fruits and vegetables per day: a theory of planned behavior perspective.

OBJECTIVE: The primary purpose of the present study was to examine the utility of the Theory of Planned Behavior (TPB) in explaining the 5-A-Day intentions and behavior of college students. A secondary purpose was to determine whether any of the TPB relationships were moderated by gender or ethnicity. DESIGN: A prospective design that asked college students to complete a baseline TPB 5-A-Day questionnaire and a fruit and vegetable consumption measure 1 week later. SETTING: Undergraduate fitness and health classes at 2 universities in the southern United States. PARTICIPANTS: 511 college students with a mean age of 19.8 years (standard deviation = 2.71). MAIN OUTCOME MEASURES: TPB variables and fruit and vegetable consumption. ANALYSES: Path analyses and invariance (ie, to examine ethnic and gender moderated) analyses. RESULTS: Affective attitude (beta = .16, P < .05) and perceived behavioral control (beta = .59, P < .05) were significant predictors of intention, which in turn was a significant predictor of behavior (beta = .32, P < .05). Follow-up invariance analyses showed that none of the TPB relationships was moderated by gender or ethnicity. CONCLUSIONS AND IMPLICATIONS: The TPB may be a useful framework on which to base a 5-A-Day intervention for male and female college students of different ethnic backgrounds.

Should carbohydrate concentration of a sports drink be less than 8% during exercise in the heat?

Our purpose was to determine if sports drinks with 6 and 8% CHO differentially affect physiological responses or run performance in the heat. Ten men ran 32 km while ingesting: placebo (P), 6% carbohydrate-electrolyte (CE6), and 8% carbohydrate-electrolyte (CE8). At 15 km, a 250 mL drink labeled with deuterium oxide (D2O) was ingested. Blood glucose and respiratory exchange ratio were significantly higher (P < 0.05) for CE6 and CE8 compared to P. Rectal temperature (T(re)) at 32 km was higher for CE8 (40.1 +/- 0.2 degrees C) compared to P (39.5 +/- 0.2 degrees C) but similar to CE6 (39.8 +/- 0.2 degrees C). D2O accumulation was not different among drink trials. Run performance was 8% faster for CE8 (1062 +/- 31 s) compared to P (1154 +/- 56 s) and similar to CE6 (1078 +/- 33 s). Confirming the ACSM Position Stand, 8% CE are acceptable during exercise in the heat and attenuate the decline in performance.

College physical education: an unrecognized agent of change in combating inactivity-related diseases.

Physical activity patterns during the young adult years are likely to be important influences on habitual physical activity during overall adult life and, consequently, have significant implications for long-term health outcomes. The potential reach and impact of college physical education on the promotion of physical activity to a large segment of the American population has been largely unrecognized. Over the last generation, many colleges and universities have reduced or eliminated their physical education requirements. Nonetheless, physical education can make important contributions in the primary prevention of inactivity-related chronic diseases and to the general education of the college student. Awareness and advocacy are needed to strengthen college physical education programs.

Endurance exercise selectively impairs prefrontal-dependent cognition.

Two experiments are reported that examine the possibility that exercise selectively influences different types of cognition. To our knowledge, these experiments represent the first attempt to study higher-cognitive processes during exercise. Theoretical thinking was guided by the transient hypofrontality hypothesis. In both experiments, athletes who exercised at a sustained, moderate pace were compared to sedentary controls on two neuropsychological tests, one that is generally regarded as heavily dependent on prefrontal cognition and one that is relatively insensitive to prefrontal operation. Results showed that during exercise performance on tests demanding prefrontal-dependent cognition was impaired, while at the same time, cognitive processes requiring little prefrontal activity were unaffected.

Physical activity patterns in recent college alumni.

Within this sample of recent college alumni, a high proportion indicated that they enjoy exercise (66.1%) and felt confident in setting their own fitness programs (79.4%). Yet, only 34.3% reported engaging in recommended levels of moderate or vigorous PA. In contrast to previous reports, rates of participation in vigorous, moderate, and strengthening-type PA did not differ between men and women. Alumni who reported that they engaged in adequate levels of moderate or vigorous PA had gained significantly less weight in the years following graduation than those who reported being insufficiently active (3.0 kg vs. 6.1 kg). Last, we noted a strong positive association between PA patterns as college seniors and current PA behavior as recent alumni.