Dietary Supplements for Improving Body Composition and Reducing Body Weight: Where Is the Evidence?

Weight-loss supplements typically fall into 1 of 4 categories depending on their hypothesized mechanism of action: products that block the absorption of fat or carbohydrate, stimulants that increase thermogenesis, products that change metabolism and improve body composition, and products that suppress appetite or give a sense of fullness. Each category is reviewed, and an overview of the current science related to their effectiveness is presented. While some weight-loss supplements produce modest effects (2 kg), especially in the long term. Some foods or supplements such as green tea, fiber, and calcium supplements or dairy products may complement a healthy lifestyle to produce small weight losses or prevent weight gain over time. Weight-loss supplements containing metabolic stimulants (e.g., caffeine, ephedra, synephrine) are most likely to produce adverse side effects and should be avoided.This is the publisher’s final pdf. The published article is copyrighted by Human Kinetics, Inc. and can be found at: http://journals.humankinetics.com/.Keywords: Starch blockers, Stimulants, Fat blockers, Exercise, Appetite suppressant

Changes in Sport Nutrition Knowledge, Attitudes/Beliefs and Behaviors Following a Two-Year Sport Nutrition Education and Life-Skills Intervention among High School Soccer Players

The purpose of this study was to examine the impact of a sport nutrition education and life-skills intervention on sport nutrition knowledge (SNK), attitudes/beliefs and dietary behaviors relevant to sport nutrition among high school (HS) soccer players. Three assessments were done over the 2-year intervention (baseline = time 1, end year 1 = time 2, end year 2 = time 3). Participants (n = 217; females = 64%; Latino = 47.5%; 14.9 ± 0.9-year; 46.5% National School Breakfast/Lunch Program) were assigned to an intervention group (IG, n = 153; 9 schools) or comparison group (CG, n = 64; 4 schools) based on geographical location. Differences over time were examined based on group, sex, socioeconomic status (SES) and race/ethnicity. The IG increased SNK scores by ~10% (time 1 = 51.6%; time 3 = 60.9%; p ≤ 0.001), with the greatest change in the female IG vs. CG and no differences in male IG vs. CG. Daily breakfast consumption was 53.7% in both groups. IG players were 3 times more likely (95%CI = 2.59, 7.77) to report trying to eat for performance (IG = 48.7% vs. CG = 30.2%). By time 3, IG players were less likely to report that \u27diet met nutritional requirements\u27 (31.6%) compared to CG (47.6%). For IG, the consumption of lunch (≥5-days/week) did not change (92.2⁻93.4%), but declined in the CG (90.6%) (p = 0.04). No other differences by sub-population (race/ethnicity, SES) were observed. Our findings indicate that HS athletes are motivated to learn and improve diet behaviors, and benefit from team-based nutrition interventions. Future interventions should consider delivery of curriculum/experiential learning during a defined training period, with messages reinforced with supports at home, school and athletic settings

Does Caffeine Intake Impact Menstrual Function? Assessment of Caffeine Intake in Active Women with and Without Exercise Induced Menstrual Dysfunction (ExMD)

It has been hypothesized that caffeine intake can directly interfere with estrogen synthesis; it is also well documented that caffeine can increase energy expenditure. Active women with ExMD are at risk for the female athlete triad, a syndrome associated with negative energy balance, leading to menstrual dysfunction and eventually poor bone health. Thus, for active women high levels of caffeine intake may suppress estrogen synthesis and simultaneously increase energy needs, contributing to ExMD

Psychological determinants of physical activity

The transition from high school (HS) to college can prove to be a difficult one for many HS students. In becoming acclimated within the academic and social realm of a college experience the individual is offered an opportunity to develop many lifestyle habits such as diet, sleep and most notably physical activity (PA) 1. Most attention addressing health concerns is placed on health indicators attuned to the college environment. However valid, such reasoning overlooks that in 2007 only 18% of 9-12th graders met the 60-minute recommendation for PA2. It also looks over the reality that sedentary behavior increases with the age of the adolescent 3. Youth athletes provide a unique opportunity in developing healthy eating habits and sustainable levels of PA, since they are often predisposed to unhealthier eating habits in HS due to their high levels of PA. As a result, a youth athlete may experience new health challenges when entering college as a traditional student, where structured PA is no longer a part of their daily life

WAVE Project: Sport Nutrition Education Resources

The WAVE~Ripples for Change: Obesity Prevention in Active Youth (WAVE) project’s primary objective is to prevent unhealthy weight gain among high school athletes through healthy eating and reduced sedentary time. Educators are familiar with the myriad of challenges in presenting nutrition, diet, and physical activity information to high school students. WAVE uses adolescent athletes’ interest in sport to draw them into the topic of sport nutrition and healthy eating; helping them apply the knowledge and skills they learned in class, on the field, and in their lives. WAVE developed and field-tested an after-school program for high school athletes that includes 7 sport nutrition lessons (30 to 45 minutes each) and 3 team-building, family and consumer sciences life-skill workshops. WAVE also developed a cloud-based data management system to support the tracking of learner profiles, survey administration, big data visualization, and automated health report generation

Coinfections by noninteracting pathogens are not independent and require new tests of interaction.

If pathogen species, strains, or clones do not interact, intuition suggests the proportion of coinfected hosts should be the product of the individual prevalences. Independence consequently underpins the wide range of methods for detecting pathogen interactions from cross-sectional survey data. However, the very simplest of epidemiological models challenge the underlying assumption of statistical independence. Even if pathogens do not interact, death of coinfected hosts causes net prevalences of individual pathogens to decrease simultaneously. The induced positive correlation between prevalences means the proportion of coinfected hosts is expected to be higher than multiplication would suggest. By modelling the dynamics of multiple noninteracting pathogens causing chronic infections, we develop a pair of novel tests of interaction that properly account for nonindependence between pathogens causing lifelong infection. Our tests allow us to reinterpret data from previous studies including pathogens of humans, plants, and animals. Our work demonstrates how methods to identify interactions between pathogens can be updated using simple epidemic models

WAVE pilot study: Creation of education tools to promote proper body composition analysis and body image awareness

Background: The Wave~Ripples for Change: Obesity Prevention in High-School Soccer Players research project is a 5-Y USDA funded project focused on building healthy nutrition, physical activity and life skills for healthy weight maintenance. The intervention includes providing face-to-face sport nutrition, physical activity and life- skills lessons, assessments of body composition, physical activity, and nutrition, and on-line immersive learning to reinforce the lessons. Objective: Develop two lessons to educate youth soccer players (age=14-19y): 1) For males, the focus is body weight and composition, and factors related to building/retaining muscle mass to reduce risk of inappropriate diet and supplement use; 2) For females, the focus is body image and associated issues about body weight and performance to reduce the risk of body dissatisfaction and disordered eating. Method: Review the research literature and identify key body composition and body image issues unique to males and females, especially active high school youth. Then develop two different lessons that will encompass the needs of each gender utilizing photos, online capabilities and common misconceptions about food, exercise and body size. Results: Research shows that active males are more interested in gaining weight, specifically muscle mass, which increases the risk of using unhealthy diets and supplements promising increased in muscle mass. Active females are more interested in being thin and small stature, which can lead to disordered eating and body image issues. Two educational lessons were developed to address the different weight and body composition issues identified for each group. For the males, the lesson focuses on understanding body composition and how it is measured, the impact of body composition on health and performance, and factors that improve body composition, including appropriate diet and exercise recommendations. For the females, the lesson focuses on understanding body composition and image, and how inappropriate beliefs about body shape and size increases the risk of body dissatisfaction. Approaches to improve body image and satisfaction are presented and discussed. Conclusions: Lessons will be tested on the WAVE pilot study high school soccer players (n=26). Based on feedback from students, changes will be made to the lessons prior to program delivery to the larger intervention study beginning in fall 2015

No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women

In endurance-trained men, an acute bout of exercise is shown to suppress post-exercise appetite, yet limited research has examined this response in women. The purpose of this study was to investigate the effect of exercise intensity on appetite and gut hormone responses in endurance-trained women. Highly-trained women (n = 15, 18–40 years, 58.4 ± 6.4 kg, VO₂ₘₐₓ = 55.2 ± 4.3 mL/kg/min) completed isocaloric bouts (500 kcals or 2093 kJ) of moderate-intensity (MIE, 60% VO2MAX) and high-intensity (HIE, 85% VO2MAX) treadmill running at the same time of day, following a similar 48-h diet/exercise period, and at least 1-week apart. Blood was drawn pre-exercise (baseline), immediately post-exercise and every 20-min for the next 60-min. Plasma concentrations of acylated ghrelin, PYY₃₋₃₆, GLP-1 and subjective appetite ratings via visual analog scale (VAS) were assessed at each time point. Acylated ghrelin decreased (p = 0.014) and PYY3–36 and GLP-1 increased (p = 0.036, p < 0.0001) immediately post-exercise, indicating appetite suppression. VAS ratings of hunger and desire to eat decreased immediately post-exercise (p = 0.0012, p = 0.0031, respectively), also indicating appetite suppression. There were no differences between exercise intensities for appetite hormones or VAS. Similar to males, post-exercise appetite regulatory hormones were altered toward suppression in highly-trained women and independent of energy cost of exercise. Results are important for female athletes striving to optimize nutrition for endurance performance