The purpose of this study was to determine the effects of carbohydrate supplementation during intense training on dietary patterns, psychological status, and markers of anaerobic and aerobic performance. Seven members of the U.S. National Field Hockey Team were matched to 7 team counterparts (N = 14). One group was blindly administered a carbohydrate drink containing 1 g·kg−1 of carbohydrate four times daily, while the remaining group blindly ingested a flavored placebo during 7 days of intense training. Subjects underwent pre- and posttraining aerobic and anaerobic assessments, recorded daily diet intake, and were administered the Profile of Mood States (POMS) psychological inventory prior to and following each practice. Results revealed that the carbohydrate-supplemented group had a greater (p < .05) total energy intake, carbohydrate intake, and change (pre vs. post) in time to maximal exhaustion following training while reporting less postpractice psychological fatigue. However, no significant differences were observed in remaining psychological, physiological, or performance-related variables.
Richard B. Kreider, Dawn Hill, Greg Horton, Michael Downes, Sarah Smith and Beth Anders
Anita Durksen, Shauna Downs, Rebecca Mollard, Laura Forbes, Geoff D.C. Ball and Jon McGavock
Physical activity interventions targeting weight status have yielded mixed results. This variability may be attributed to compensatory changes in dietary patterns after increasing physical activity (PA) levels. Therefore, we sought to determine whether dietary patterns varied with time spent in vigorous-intensity PA in youth.
Cross-sectional analysis of 330 youth enrolled in a school-based prospective cohort in central Alberta. Physical activity was assessed with waist mounted accelerometers (Actical) worn for 7 days. Main outcomes included consumption of unhealthy foods and the unhealthy food index obtained from a validated web-based 24-hour dietary recall instrument. Secondary outcomes included macronutrient intake, food group (Canada’s Food Guide to Healthy Eating) intake, and diet quality.
Compared with youth participating in < 7 min/ day of vigorous physical activity, those achieving ≥ 7 min/day displayed no change in healthy or unhealthy food consumption. However, linear regression suggests a modest association between diet quality and vigorous-intensity PA.
These data demonstrate that in this cohort of Canadian youth, time spent being physically active is associated with healthier dietary patterns and not with increased consumption of unhealthy foods.
Rebecca T. Viner, Margaret Harris, Jackie R. Berning and Nanna L. Meyer
The purpose of this study was to assess energy availability (EA) and dietary patterns of 10 adult (29–49 years) male (n = 6) and female (n = 4) competitive (USA Cycling Category: Pro, n = 2; 1–4, n = 8) endurance cyclists (5 road, 5 off-road), with lower than expected bone mineral density (BMD; Z score < 0) across a season. Energy intake (EI) and exercise energy expenditure during preseason (PS), competition (C), and off-season (OS) were estimated from 3-day dietary records, completed once per month, across a cycling season. BMD was measured by DXA at 0 months/5 months/10 months. The Three-Factor Eating Questionnaire (TFEQ) was used to assess cognitive dietary restraint. Seventy percent of participants had low EA [(LEA); < 30 kcal·kg fat-free mass (FFM)−1·day−1] during PS, 90% during C, and 80% during OS (range: 3–37 kcal·kg FFM−1·day−1). Ninety percent of cyclists had LEA during ≥ 1 training period, and 70% had LEA across the season. Seventy percent of cyclists were identified as restrained eaters who consciously restrict EI as a means of weight control. Mean daily carbohydrate intake was below sport nutrition recommendations during each training period (PS: 3.9 ± 1.1 g·kg−1·day−1, p < .001; C: 4.3 ± 1.4 g·kg−1·day−1, p = .005; OS: 3.7 ± 1.4 g·kg−1·day−1, p = .01). There were no differences in EA and EI·kg−1 between male and female cyclists and road and off-road cyclists. Low EI, and specifically low carbohydrate intake, appears to be the main contributor to chronic LEA in these cyclists. Adult male and female competitive road and off-road cyclists in the United States may be at risk for long-term LEA. Further studies are needed to explore strategies to prevent and monitor long-term LEA in these athletes.
Maria José Tormo, Carmen Navarro, Maria-Dolores Chirlaque, Xavier Barber, Silvia Argilaga, Antonio Agudo, Pilar Amiano, Aurelio Barricarte, Jose M. Beguiristain, Miren Dorronsoro, Carlos Alberto González, Carmen Martínez, José Ramón Quirós and Mauricio Rodríguez
This study evaluated the dietary pattern of foods and nutrients according to levels of vigorous leisure time physical activity (PA) assessed at recruitment within the Spanish cohort of the European Prospective Investigation on Cancer (EPIC) study (37,287 healthy volunteers with complete information). We used a validated PA questionnaire (PAQ) to measure the weekly frequency and duration of different kinds of sport activities. For dietary assessment, we used a validated diet history questionnaire that included all items consumed with a frequency of at least twice a month. We tested differences in food and nutrient intake according to PA duration by means of both an analysis of variance and an analysis of covariance adjusted for confounding factors. Linear increases or decreases in food and nutrient intake across PA levels were tested by means of a regression analysis. Only 11% of men and 6% of women performed at least 3 hours/week of intense PA, which is similar to current recommendations. Overall, main nutrient and total energy intakes were similar across different PA levels (<2% change in total energy intake between extreme PA categories). However, the intake of some foods and vitamins did significantly (p ≤ .05) increase as PA increased. The average gender-weighted percentage change in the intake of food and vitamins increased when moving from the lowest levels of PA to the highest. There was an increase in the intake of the following: 15.9% in vegetables, 6.7% in fruit, 9% in fish, 5.6% in dairy products, 10% in vitamin C, 5.9% in vitamin E, 7.2% in retinol, 19.7% in total carotene, 40.1% in α-carotene, 20.4% in ß-carotene, 11.2% in licopene, and 26.1% in lutein. BMI, which was above average for the cohort (mean ± SD: 28.4 ± 4.2), decreased steadily when PA increased. To sum up, in this large Spanish cohort, the differences in dietary intake relative to levels of PA were not found either in the amount of total energy consumed nor in the number of main macronutrients but rather in the intake of certain foods which, while having very little or moderate caloric content, are very rich in highly bioactive elements such as vitamins and provitamins.
Louise Capling, Janelle A. Gifford, Kathryn L. Beck, Victoria M. Flood, Gary J. Slater, Gareth S. Denyer and Helen T. O’Connor
( Hu, 2002 ). A diet quality index or diet quality score applies a scoring system that compares usual intake or dietary patterns against dietary guidelines or other predefined criteria, with a higher score being positively associated with a more favorable dietary intake ( Kant, 1996 ; Waijers et
Simone Dohle, Brian Wansink and Lorena Zehnder
The goal of this qualitative study is to identify common beliefs and behaviors related to exercise and diet.
Data were collected in focus group discussions with regular exercisers who were physically active between 1 and 5 h per week. Exercise objectives, beliefs and behaviors regarding food intake before, during, and after exercise, consumption of sport supplements, and dietary patterns on sedentary days were explored. All focus groups were audio-taped and transcribed verbatim. Transcripts were analyzed using a grounded theory approach.
Participants reported that they reward themselves for being active by consuming food. Other exercisers had specific beliefs about dietary needs and how to compensate for exercise-induced losses along with exercise-related food likes and dislikes. The participants’ food intake also depended on their personal exercise objectives, such as the goal of performing well in competitions. External and physiological factors also played a role in determining participants’ dietary patterns.
Results of this study show that exercising and dietary patterns are closely intertwined. In addition, we articulate new hypotheses and outline a research agenda that can help improve how regular exercisers eat.
Ben Desbrow, Nicholas A. Burd, Mark Tarnopolsky, Daniel R. Moore and Kirsty J. Elliott-Sale
Adolescent, female, and masters athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the specific demands of age- and gender-related physiological changes. Dietary education and recommendations for these special population athletes require a focus on eating for long-term health, with special consideration given to “at-risk” dietary patterns and nutrients (e.g., sustained restricted eating, low calcium, vitamin D and/or iron intakes relative to requirements). Recent research highlighting strategies to address age-related changes in protein metabolism and the development of tools to assist in the management of Relative Energy Deficiency in Sport are of particular relevance to special population athletes. Whenever possible, special population athletes should be encouraged to meet their nutrient needs by the consumption of whole foods rather than supplements. The recommendation of dietary supplements (particularly to young athletes) overemphasizes their ability to manipulate performance in comparison with other training/dietary strategies.
Catherine Applegate, Mackenzie Mueller and Krystle E. Zuniga
Diet composition can affect systemic pH and acid-base regulation, which may in turn influence exercise performance. An acidic environment in the muscle impairs performance and contributes to fatigue; therefore, current trends in sports nutrition place importance on maximizing the alkalinity of the body with ergogenic aids and dietary strategies. This review examines the evidence on the effects of dietary manipulations on acid load and exercise performance. Ten studies that investigated the effect of high versus low dietary acid loads on athletic performance generally identified that low dietary acid loads increased plasma pH, but did not consistently improve exercise performance at maximal or submaximal exercise intensities. In addition, the few studies conducted have several limitations including lack of female subjects and use of exercise tests exclusive to cycling or treadmill running. Although the research does not strongly support a performance benefit from low dietary acid loads, a more alkaline dietary pattern may be beneficial for overall health, as dietary induced acidosis has been associated with greater risk of cardiovascular disease and bone disease. The review includes dietary recommendations for athletes to reduce dietary acid load while still meeting sports nutrition recommendations.
Amelia Ferro, Guadalupe Garrido, Jorge Villacieros, Javier Pérez and Lena Grams
Physical condition and an optimized diet are relevant to enhance performance and recovery. The diet composition and meal frequency of eleven elite wheelchair basketball players were estimated using a 3-day food-weighing diary in two months during the precompetitive-period. Performance was determined through a 20 m sprint test. The players consumed 4.2 ± 0.8 meals/day in May and 4.5 ± 0.9 meals/day in June, resulting in total energy intakes of 2492 ± 362 kcal/d and 2470 ± 497 kcal/d, respectively. The macronutrient distribution was 3.8 ± 1.3 g/kg carbohydrates, 1.7 ± 0.6 g/kg protein, and 36 ± 5% of energy derived from fat in May, and 4.2 ± 1.9 g/kg carbohydrates, 1.5 ± 0.5 g/kg protein and 32 ± 5% of energy derived from fat in June. The maximum velocity of the sprint test improved from 4.77 ± 0.31 m/s in May to 5.19 ± 0.23 m/s in June. Our results revealed carbohydrate intake below and fat intake above recommendations, but improvements of dietary patterns. Further nutritional advice is necessary to ensure health and performance improvements.
Rochelle Rocha Costa, Adriana Cristine Koch Buttelli, Alexandra Ferreira Vieira, Leandro Coconcelli, Rafael de Lima Magalhães, Rodrigo Sudatti Delevatti and Luiz Fernando Martins Kruel
levels was not influenced by food control tools. Trials that adopted tools to monitor the dietary patterns of the participants (18 studies) were associated with significant TC reductions (ES: −0.321; 95% CI, −0.578 to −0.065; P = .01; I 2 : 53%; −6.01 mg·dL −1 ), as were those that did not cite the