Low Carbohydrate, High Fat Diet Alters the Oral Microbiome without Negating the Nitrite Response to Beetroot Juice Supplementation.

A low carbohydrate, high fat (LCHF) diet in athletes increases fat oxidation but impairs sports performance, potentially due to impaired exercise economy. Dietary nitrate supplementation can improve exercise economy via an increase in nitric oxide production, which is initiated by the reduction of nitrate to nitrite within the oral cavity. This reaction is dependent on the presence of nitrate-reducing oral bacteria, which can potentially be altered by dietary changes, including a LCHF diet. This study explored the effect of a LCHF diet on the oral microbiome and subsequent changes to plasma nitrite concentration following nitrate supplementation. Following five days of LCHF or high carbohydrate (HCHO) control dietary intervention, highly trained male race walkers consumed 140 mL beetroot juice containing 8.4 mmol nitrate; they then provided (a) blood samples for plasma nitrate and nitrite analysis and (b) saliva samples for 16S rRNA sequencing of the oral microbiome. The LCHF diet (n = 13) reduced oral bacterial diversity and changed the relative abundance of the genera Neisseria (+10%), Fusobacteria (+3%), Prevotella (-9%), and Veillonella (-4%), with no significant changes observed following the HCHO diet (n = 11). Following beetroot juice ingestion, plasma nitrite concentrations were higher for the LCHF diet compared to the HCHO diet (p = 0.04). However, the absence of an interaction with the trial (pre-post) (p = 0.71) suggests that this difference was not due to the dietary intervention. In summary, we found an increase in plasma nitrate and nitrite concentrations in response to nitrate supplementation independent of diet. This suggests the oral microbiome is adaptive to dietary changes and can maintain a nitrate reduction capacity despite a decrease in bacterial diversity following the LCHF diet.

Client experiences and confidence in nutrition advice delivered by registered exercise professionals.

OBJECTIVES: The aims of this cross-sectional study were to describe the client experiences of registered exercise professionals (REP) in regard to nutrition advice, and to identify factors considered important when selecting a REP. DESIGN: A convenience sample of fitness facility-users were recruited. Participants completed a 46 item online questionnaire. METHOD: Frequency distributions were calculated for nutrition advice received from a REP, confidence in the nutrition advice received, and factors considered when selecting a REP. The effect of sex and level of education on participant responses were investigated. RESULTS: A total of 455 individuals participated, of which 55.6% had worked with a REP. Participants working with a REP had received nutrition advice on body fat loss (77.4%), muscle gain (78.7%), and clinical nutrition (51.9%). Sex and level of education did not influence confidence in nutrition advice, with 60.7% of participants reporting being 'very or extremely confident' in the nutrition advice. Over half of participants (58.3%) prefer to work with a REP who offers nutrition advice. Basic and personal professional conduct were identified as 'very or extremely important' by >70% of participants when selecting a REP. CONCLUSION: Clients of REP prefer to work with a REP who provides nutrition advice and are generally confident in this advice. Educating fitness facility-users on the nutrition scope of practice of REP and promoting the role of accredited nutrition professionals should be advocated. Encouraging REP to work collaboratively with nutrition professionals will help ensure clients receive appropriate nutrition care, while better allowing REP to remain within their scope of practice.

Body composition of elite Olympic combat sport athletes.

Physique traits of a range of elite athletes have been identified; however, few detailed investigations of Olympic combat sports (judo, wrestling, taekwondo and boxing) exist. This is surprising given the importance of body composition in weight category sports. We sought to develop a descriptive database of Olympic combat sport athletes, compare variables relative to weight division and examine differences within and between sports. Additionally, we investigated the appropriateness of athletes' self-selected weight classes compared to an internationally recognised classification system (the NCAA minimum wrestling weight scheme used to identify minimum 'safe' weight). Olympic combat sport athletes (56♂, 38♀) had body mass (BM), stretch stature and dual-energy X-ray absorptiometry derived body composition assessed within 7-21 days of competition. Most athletes were heavier than their weight division. Sport had an effect (p < .05) on several physique traits, including; lean mass, lean mass distribution, stretch stature and BMI. BM was strongly positively correlated (r > 0.6) with; fat free mass, fat mass and body fat percentage, however, was not predictive of total mass/weight division. The Olympic combat sports differ in competitive format and physiological requirements, which is partly reflected in athletes' physique traits. We provide reference ranges for lean and fat mass across a range of BM. Lighter athletes likely must utilise acute weight loss in order to make weight, whereas heavier athletes can potentially reduce fat mass.

International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics.

The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete's well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a "food first" policy should underpin an Athlete's nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.

Caffeine content of pre-workout supplements commonly used by Australian consumers.

The stimulant properties of caffeine are often promoted in pre-workout supplements (PWS) to assist with training, reduce the perception of fatigue, and for some brands, assist body fat loss. While manufacturers of PWS often indicate the inclusion of significant amounts of caffeine, no independent verification of the caffeine content of these products exists. The aim of this investigation was to independently assess the caffeine content of popular PWS in Australia and compare these values to nutrition information panel data. Fifteen PWS were tested for their caffeine content (both within and between batches of the same product). The caffeine content of selected PWS ranged from 91 to 387 mg·serve-1 . Only 6 of the 15 PWS nutrition information panels included details on caffeine content. The percent of caffeine present ranged from 59% to 176% of packaging claims. All but one PWS contained a variation of caffeine within and between batches that was considered "practically" significant (ie, ≥40 mg·serve-1 variation). Consumers are likely to be exposed to large and variable caffeine doses if ingesting PWS. Product information panels do little to improve consumer awareness of likely caffeine intakes.

A randomised controlled intervention study investigating the efficacy of carotenoid-rich fruits and vegetables and extra-virgin olive oil on attenuating sarcopenic symptomology in overweight and obese older adults during energy intake restriction: protocol paper.

BACKGROUND: Weight loss interventions have not been advocated for overweight/obese older adults due to potential loss of skeletal muscle and strength impacting on physical function with potential loss of independence. Carotenoids and polyphenols are inversely associated with sarcopenic symptomology. This paper reports the protocol of a study evaluating the efficacy of a high-protein, energy restricted diet rich in carotenoids and polyphenols on body composition, muscle strength, physical performance and quality of life in overweight and obese older adults. METHODS: This randomised controlled clinical trial will recruit community-dwelling, healthy overweight and obese older adults (≥60 years) for a 12-week weight loss intervention. Seventy-three participants will be recruited and randomized to an energy restricted (~30% restriction), isocaloric diet (30% protein; 30% carbohydrate; 40% fat) enriched with either: a) 375 g/d of high carotenoid vegetables, 300 g/d high carotenoid fruit, and 40-60 ml extra-virgin olive oil (EVOO); or b) 375 g/d of lower carotenoid vegetables, 300 g/d lower carotenoid fruit, and 40-60 ml Polyunsaturated fatty acid (PUFA) based oil. All participants will receive individual dietary counselling each fortnight for the duration of the study and will be asked to maintain their habitual level of physical activity throughout the study. The primary outcome will be appendicular skeletal muscle (ASM) assessed by dual energy X-ray absorptiometry (DXA). Secondary outcomes will include body weight, fat-free mass (FFM), fat mass (FM), muscle strength (Isometric hand-grip strength), physical performance (Short Physical Performance Battery), physical activity (International Physical Activity Questionnaire) and health related quality of life (SF-36). Outcomes will be measured at baseline and at week 12. DISCUSSION: The results of this study will provide a novel insight relating to the potential influence of high carotenoid and polyphenol intakes on attenuation of ASM during dietary energy-restricted weight loss in overweight and obese older adults. TRIAL REGISTRATION: The trial was registered on the Australia New Zealand Clinical Trials Register ( ACTRN12616001400459 ); Trial registration date: 10th October, 2016.

The Effect of Water Loading on Acute Weight Loss Following Fluid Restriction in Combat Sports Athletes.

Novel methods of acute weight loss practiced by combat sport athletes include "water loading," the consumption of large fluid volumes for several days prior to restriction. We examined claims that this technique increases total body water losses, while also assessing the risk of hyponatremia. Male athletes were separated into control (n = 10) and water loading (n = 11) groups and fed a standardized energy-matched diet for 6 days. Days 1-3 fluid intake was 40 and 100 ml/kg for control and water loading groups, respectively, with both groups consuming 15 ml/kg on Day 4 and following the same rehydration protocol on Days 5 and 6. We tracked body mass (BM), urine sodium, urine specific gravity and volume, training-related sweat losses and blood concentrations of renal hormones, and urea and electrolytes throughout. Physical performance was assessed preintervention and postintervention. Following fluid restriction, there were substantial differences between groups in the ratio of fluid input/output (39%, p < .01, effect size = 1.2) and BM loss (0.6% BM, p = .02, effect size = 0.82). Changes in urine specific gravity, urea and electrolytes, and renal hormones occurred over time (p < .05), with an interaction of time and intervention on blood sodium, potassium, chloride, urea, creatinine, urine specific gravity, and vasopressin (p < .05). Measurements of urea and electrolyte remained within reference ranges, and no differences in physical performance were detected over time or between groups. Water loading appears to be a safe and effective method of acute BM loss under the conditions of this study. Vasopressin-regulated changes in aquaporin channels may potentially partially explain the mechanism of increased body water loss with water loading.

Influence of body composition on physiological responses to post-exercise hydrotherapy.

This study examined the influence of body composition on temperature and blood flow responses to post-exercise cold water immersion (CWI), hot water immersion (HWI) and control (CON). Twenty-seven male participants were stratified into three groups: 1) low mass and low fat (LM-LF); 2) high mass and low fat (HM-LF); or 3) high mass and high fat (HM-HF). Experimental trials involved a standardised bout of cycling, maintained until core temperature reached 38.5°C. Participants subsequently completed one of three 15-min recovery interventions (CWI, HWI, or CON). Core, skin and muscle temperatures, and limb blood flow were recorded at baseline, post-exercise, and every 30 min following recovery for 240 min. During CON and HWI there were no differences in core or muscle temperature between body composition groups. The rate of fall in core temperature following CWI was greater in the LM-LF (0.03 ± 0.01°C/min) group compared to the HM-HF (0.01 ± 0.001°C/min) group (P = 0.002). Muscle temperature decreased to a greater extent during CWI in the LM-LF and HM-LF groups (8.6 ± 3.0°C) compared with HM-HF (5.1 ± 2.0°C, P < 0.05). Blood flow responses did not differ between groups. Differences in body composition alter the thermal response to post-exercise CWI, which may explain some of the variance in the responses to CWI recovery.

Weight Management Practices of Australian Olympic Combat Sport Athletes.

PURPOSE: Combat sport athletes undertake chronic and rapid weight loss (RWL) practices to qualify for weight divisions lower than their training weight. Variation between sports in the prevalence, methods, and magnitude of weight loss as well as recovery practices may be influenced by factors including competition level and culture. Differences in methodologies of previous research in combat sports make direct comparisons difficult; thus, this study aimed to examine weight loss practices among all Olympic combat sports in Australia, using standardized methodology. METHODS: High-caliber competitors in wrestling, boxing, judo, and taekwondo (n = 260) at Australian competitions were surveyed using a validated tool that provides quantification of how extreme an athlete's weight loss practices are: the rapid weight loss score (RWLS). Additional qualitative and quantitative survey data were also collected. RESULTS: Neither sport, sex, nor weight division group had an effect on RWLS; however, a significant effect of athlete caliber was detected (F2,215 = 4.953, mean square error = 4.757, P = .00792). Differences between sports were also evident for most weight ever lost in order to compete (H = 19.92, P = .0002), age at which weight cutting began (H = 16.34, P = .001), and selected methods/patterns of RWL (P < .001). Weight cycling between competitions was common among all sports as were influences on athlete's behaviors. CONCLUSIONS: Although many similarities in weight loss practices and experiences exist between combat sports, specific differences were evident. Nuanced, context/culturally specific guidelines should be devised to assist fighters' in optimizing performance while minimizing health implications.

Individualised dietary strategies for Olympic combat sports: Acute weight loss, recovery and competition nutrition.

Olympic combat sports separate athletes into weight divisions, in an attempt to reduce size, strength, range and/or leverage disparities between competitors. Official weigh-ins are conducted anywhere from 3 and up to 24 h prior to competition ensuring athletes meet weight requirements (i.e. have 'made weight'). Fighters commonly aim to compete in weight divisions lower than their day-to-day weight, achieved via chronic and acute manipulations of body mass (BM). Although these manipulations may impair health and absolute performance, their strategic use can improve competitive success. Key considerations are the acute manipulations around weigh-in, which differ in importance, magnitude and methods depending on the requirements of the individual combat sport and the weigh-in regulations. In particular, the time available for recovery following weigh-in/before competition will determine what degree of acute BM loss can be implemented and reversed. Increased exercise and restricted food and fluid intake are undertaken to decrease body water and gut contents reducing BM. When taken to the extreme, severe weight-making practices can be hazardous, and efforts have been made to reduce their prevalence. Indeed some have called for the abolition of these practices altogether. In lieu of adequate strategies to achieve this, and the pragmatic recognition of the likely continuation of these practices as long as regulations allow, this review summarises guidelines for athletes and coaches for manipulating BM and optimising post weigh-in recovery, to achieve better health and performance outcomes across the different Olympic combat sports.

Acute-Weight-Loss Strategies for Combat Sports and Applications to Olympic Success.

It is common for athletes in weight-category sports to try to gain a theoretical advantage by competing in weight divisions that are lower than their day-to-day body mass (BM). Weight loss is achieved not only through chronic strategies (body-fat losses) but also through acute manipulations before weigh-in ("making weight"). Both have performance implications. This review focuses on Olympic combat sports, noting that the varied nature of regulations surrounding the weigh-in procedures, weight requirements, and recovery opportunities in these sports provide opportunity for a wider discussion of factors that can be applied to other weight-category sports. The authors summarize previous literature that has examined the performance effects of weightmaking practices before investigating the physiological nature of these BM losses. Practical recommendations in the form of a decision tree are provided to guide the achievement of acute BM loss while minimizing performance decrements.

Prevalence, knowledge and attitudes relating to ß-alanine use among professional footballers.

OBJECTIVES: To investigate ß-alanine supplementation use and level of knowledge amongst professional footballers. DESIGN: Cross-sectional survey of Australian professional football players. METHODS: Questionnaires assessing ß-alanine supplementation behaviours, level of knowledge and sources of information were completed by professional rugby union (RU) (n=87), rugby league (RL) (n=180) and Australian Rules Football (ARF) (n=303) players. RESULTS: Approximately 61% of athletes reported ß-alanine use, however use by ARF football players (44%) was lower than that of RU (80%) and RL players (80%). The majority of respondents were not using ß-alanine in accordance with recommendations. Only 35% of the participants were able to correctly identify the potential benefits of ß-alanine supplementation. The main information sources that influenced players' decision to use ß-alanine were strength and conditioning coach (71%) and dietitian (52%). Forty-eight per cent of athletes never read labels prior to supplementing and only 11% completed their own research on ß-alanine. Compared to RL and ARF players, RU players had both a greater knowledge of ß-alanine supplementation and better supplementation practices. CONCLUSIONS: Despite over half the surveyed professional footballers using ß-alanine, the majority of athletes used ß-alanine in a manner inconsistent with recommendations. A better understanding of the environment and culture within professional football codes is required before supplement use becomes consistent with evidence based supplement recommendations.

Changes in the Supplementation Practices of Elite Australian Swimmers Over 11 Years.

Thirty nine elite Australian swimmers (13 AIS, 26 OTHER) completed a standardized questionnaire regarding their supplement use during a pre competition camp. The data were compared with a similar study conducted 11 years earlier (11 AIS, 23 OTHER) and framed around the classification system of the Sport Supplement Program of the Australian Institute of Sport. The prevalence of supplement use remained constant over time (2009: 97%, 1998: 100%). However, the current swimmers used a greater number of dietary supplements (9.2 ± 3.7 and 5.9 ± 2.9; p = .001), accounted for by an increase in the reported use of supplements with a greater evidence base (Sports Foods, Ergogenics, and Group B supplements). In contrast, fewer supplements considered less reputable (Group C and D) were reported by the 2009 cohort (0.7 ± 1.0 and 1.6 ± 1.3; p = .003). AIS swimmers reported a greater use of Ergogenics (4.3 ± 1.8 and 3.1 ± 1.7; p = .002), and less use of Group C and D supplements overall (0.8 ± 1.2 and 1.3 ± 1.2; p = .012), which was explained primarily by a smaller number of these supplements reported by the 2009 group (1998 AIS: 1.5 ± 1.4, 2009 AIS: 0.2 ± 0.6; p = .004). Although the prevalence of supplement use has not changed over time, there has been a significant increase in the number and type of products they are using. The potential that these changes can be attributed to a Sports Supplement Program merit investigation.

Regain in Body Mass After Weigh-In is Linked to Success in Real Life Judo Competition.

We examined the relationship between the regain of body mass (BM) after weigh-in and success in real-life judo competition. Eighty-six (36 females, 50 males) senior judoka volunteered for this observational study of an international judo competition. Subjects were weighed at the official weigh-in and one hour before their first competition fight (15-20 hr later). Regain in BM after weigh-in was compared between medal winners and nonmedalists, winners and losers of each fight, males and females and across weight divisions. Heavyweights were excluded from analysis. Prefight BM was greater than BM at official weigh-in for both males and females, with % BM gains of 2.3 ± 2.0 (p ≤ .0001; ES= 1.59; CI95% [1.63, 2.98]) and 3.1 ± 2.2 (p ≤ .0001; ES = 2.03; CI95% [2.30, 3.89]), respectively. No significant differences were found between weight divisions for post weigh-in BM regain. Differences in post weigh-in BM regain were significantly higher in medal winners than nonmedalists for males and females combined (1.4 ± 0.4% BM; p = .0026; ES= 0.69; CI95% [0.05, 2.34]) and for males alone (1.5 ± 0.6% BM; p = .017; ES= 0.74; CI95% [0.02, 2.64]), but not for females (1.2 ± 0.7% BM; p = .096; ES = 0.58; CI95% [-0.02, 2.31]). Differences in BM regain after weigh-in between winners and losers were significant across all fights (0.9 ± 0.3% BM; p = .0021; ES= 0.43; CI95% [0.31, 1.41]) but not for first round fights (0.8 ± 0.5% BM; p = .1386, ES = 0.38; CI95% [-0.26, 1.86]). Winners showed a greater regain in BM post weigh-in than losers. This may reflect the greater magnitude of the BM loss needed to achieve weigh-in targets which also relates to the experience level of successful athletes.

Increasing Protein Distribution Has No Effect on Changes in Lean Mass During a Rugby Preseason.

Increasing the frequency of protein consumption is recommended to stimulate muscle hypertrophy with resistance exercise. This study manipulated dietary protein distribution to assess the effect on gains in lean mass during a rugby preseason. Twenty-four developing elite rugby athletes (age 20.1 ± 1.4 years, mass 101.6 ± 12.0 kg; M ± SD) were instructed to consume high biological value (HBV) protein at their main meals and immediately after resistance exercise while limiting protein intake between meals. To manipulate protein intake frequency, the athletes consumed 3 HBV liquid protein supplements (22 g protein) either with main meals (bolus condition) or between meals (frequent condition) for 6 weeks in a 2 × 2 crossover design. Dietary intake and change in lean mass values were compared between conditions by analysis of covariance and correlational analysis. The dietary manipulation successfully altered the protein distribution score (average number of eating occasions containing > 20 g of protein) to 4.0 ± 0.8 and 5.9 ± 0.7 (p < .01) for the bolus and frequent conditions, respectively. There was no difference in gains in lean mass between the bolus (1.4 ± 1.5 kg) and frequent (1.5 ± 1.4 kg) conditions (p = .91). There was no clear effect of increasing protein distribution from approximately 4-6 eating occasions on changes in lean mass during a rugby preseason. However, other dietary factors may have augmented adaptation.

Supplement Use of Elite Australian Swimmers.

This study examined the influence the Australian Institute of Sport (AIS) Sport Supplement Program had on supplement practices of elite Australian swimmers, comparing those guided by the Program with others in the same national team. Thirty-nine elite swimmers (13 AIS, 26 Other; 20 female, 19 male; age 21.8 ± 3.3 y) completed a questionnaire investigating supplement use. Ninety-seven percent of swimmers reported taking supplements or sports foods over the preceding 12 months. AIS swimmers reported using more total brands (p = .02) and supplements considered Ergogenic (p = .001) than Other swimmers who used more supplements considered to be lacking scientific support (p = .028). Swimmers rated the risk of a negative outcome from the use of supplements available in Australia (Mdn = 3.0) as less than the risk of supplements from international sources (Mdn = 4.0; p < .001). AIS swimmers were more likely to report dietitians (p < .001) and sports physicians (p = .017) as advisors of their supplement use. Other swimmers more frequently reported fellow athletes as a source of supplement advice (p = .03). AIS swimmers sourced a greater percentage of their supplements from an organized program (94 ± 16%) compared with Other (40 ± 32%; p < .001) who sourced a greater percentage (30 ± 30%) of their dietary supplements from supermarkets. These findings suggest that swimmers influenced by this sport supplement program more frequently use supplements that are recommended by allied health trained individuals, classified as evidence based and provided by the program.

Dietary Intake of Competitive Bodybuilders.

BACKGROUND: Competitive bodybuilders are well known for extreme physique traits and extremes in diet and training manipulation to optimize lean mass and achieve a low body fat. Although many of the dietary dogmas in bodybuilding lack scientific scrutiny, a number, including timing and dosing of high biological value proteins across the day, have more recently been confirmed as effective by empirical research studies. A more comprehensive understanding of the dietary intakes of bodybuilders has the potential to uncover other dietary approaches, deserving of scientific investigation, with application to the wider sporting, and potential health contexts, where manipulation of physique traits is desired. OBJECTIVE: Our objective was to conduct a systematic review of dietary intake practices of competitive bodybuilders, evaluate the quality and currency of the existing literature, and identify research gaps to inform future studies. METHODS: A systematic search of electronic databases was conducted from the earliest record until March 2014. The search combined permutations of the terms 'bodybuilding', 'dietary intake', and 'dietary supplement'. Included studies needed to report quantitative data (energy and macronutrients at a minimum) on habitual dietary intake of competitive bodybuilders. RESULTS: The 18 manuscripts meeting eligibility criteria reported on 385 participants (n = 62 women). Most studies were published in the 1980-1990s, with three published in the past 5 years. Study methodological quality was evaluated as poor. Energy intake ranged from 10 to 24 MJ/day for men and from 4 to 14 MJ/day for women. Protein intake ranged from 1.9 to 4.3 g/kg for men and from 0.8 to 2.8 g/kg for women. Intake of carbohydrate and fat was <6 g/kg/day and below 30% of energy, respectively. Carbohydrate intakes were below, and protein (in men) intakes were higher than, the current recommendations for strength athletes, with no consideration for exploration of macronutrient quality or distribution over the day. Energy intakes varied over different phases of preparation, typically being highest in the non-competition (>6 months from competition) or immediate post-competition period and lowest during competition preparation (≤6 months from competition) or competition week. The most commonly reported dietary supplements were protein powders/liquids and amino acids. The studies failed to provide details on rationale for different dietary intakes. The contribution of diet supplements was also often not reported. When supplements were reported, intakes of some micronutrients were excessive (~1000% of US Recommended Dietary Allowance) and above the tolerable upper limit. CONCLUSION: This review demonstrates that literature describing the dietary intake practices of competitive bodybuilders is dated and often of poor quality. Intake reporting required better specificity and details of the rationale underpinning the use. The review suggests that high-quality contemporary research is needed in this area, with the potential to uncover dietary strategies worthy of scientific exploration.

The effect of a whey protein supplement dose on satiety and food intake in resistance training athletes.

OBJECTIVE: Many athletes perform resistance training and consume dietary protein as a strategy to promote anabolic adaptation. Due to its high satiety value, the regular addition of supplemented dietary protein could plausibly displace other key macronutrients such as carbohydrate in an athlete's diet. This effect will be influenced by the form and dose of protein. Therefore, this study assessed the impact of liquid whey protein dose manipulation on subjective sensations of appetite and food intake in a cohort of athletes. DESIGN: Ten male athletes who performed both resistance and aerobic (endurance) training (21.2 ± 2.3 years; 181.7 ± 5.7 cm and 80.8 ± 6.1 kg) were recruited. In four counter-balanced testing sessions they consumed a manipulated whey protein supplement (20, 40, 60 or 80 g protein) 1 hour after a standardised breakfast. Subsequent energy intake was measured 3 hours after the protein supplement using an ad libitum test meal. Subjective appetite sensations were measured periodically during the test day using visual analogue scales. RESULTS: All conditions resulted in a significant decrease in ratings of hunger (50-65%; P < 0.05) at the time of supplement consumption. However, there were no significant differences between the conditions at any time point for subjective appetite sensations or for energy consumed in the ad libitum meal: 4382 ± 1004, 4643 ± 982, 4514 ± 1112, 4177 ± 1494 kJ respectively. CONCLUSION: Increasing whey protein supplement dose above 20 g did not result in a measurable increase in satiety or decrease in food intake. However, the inclusion of additional whey protein supplementation where not otherwise consumed could plausibly reduce dietary intake.

The Measurement and Interpretation of Dietary Protein Distribution During a Rugby Preseason.

Evidence suggests that increasing protein distribution may be desirable to promote muscle protein synthesis (MPS) in combination with resistance exercise. However, there is a threshold above which additional protein consumption has limited benefit for MPS and may promote protein loss due to increased oxidation. This study aimed to measure daily protein intake and protein distribution in a cohort of rugby players. Twenty-five developing elite rugby union athletes (20.5 ± 2.3 years, 100.2 ± 13.3 kg, 184.4 ± 7.4 cm) were assessed at the start and end of a rugby preseason. Using a 7-day food diary the reported daily protein intake was 2.2 ± 0.7 g · kg · day(-1) which exceeds daily recommendations. The reported carbohydrate intake was 3.6 ± 1.3 g · kg · day(-1) which may reflect a suboptimal intake or dietary underreporting. In general, the rugby athletes were regularly consuming more than 20 g of protein; 3.8 ± 0.9 times per day (68 ± 18% of eating occasions). In addition to documenting current dietary intakes, an excess protein estimation score was calculated to determine how frequently the rugby athletes consumed protein above a known effective dose with a margin of error. 2.0 ± 0.9 eating occasions contained protein in excess of doses (20 g) known to promote MPS. Therefore, it is currently unclear whether the consumption of regular large doses of protein will benefit rugby athletes via increasing protein distribution, or whether high protein intakes may have unintended effects including a reduction in carbohydrate and/or energy intake.

Reliability and effect of sodium bicarbonate: buffering and 2000-m rowing performance.

PURPOSE: The aim of this study was to determine the effect and reliability of acute and chronic sodium bicarbonate ingestion for 2000-m rowing ergometer performance (watts) and blood bicarbonate concentration [HCO3-]. METHODS: In a crossover study, 7 well-trained rowers performed paired 2000-m rowing ergometer trials under 3 double-blinded conditions: (1) 0.3 grams per kilogram of body mass (g/kg BM) acute bicarbonate; (2) 0.5 g/kg BM daily chronic bicarbonate for 3 d; and (3) calcium carbonate placebo, in semi-counterbalanced order. For 2000-m performance and [HCO3-], we examined differences in effects between conditions via pairwise comparisons, with differences interpreted in relation to the likelihood of exceeding smallest worthwhile change thresholds for each variable. We also calculated the within-subject variation (percent typical error). RESULTS: There were only trivial differences in 2000-m performance between placebo (277 ± 60 W), acute bicarbonate (280 ± 65 W) and chronic bicarbonate (282 ± 65 W); however, [HCO3-] was substantially greater after acute bicarbonate, than with chronic loading and placebo. Typical error for 2000-m mean power was 2.1% (90% confidence interval 1.4 to 4.0%) for acute bicarbonate, 3.6% (2.5 to 7.0%) for chronic bicarbonate, and 1.6% (1.1 to 3.0%) for placebo. Postsupplementation [HCO3-] typical error was 7.3% (5.0 to 14.5%) for acute bicarbonate, 2.9% (2.0 to 5.7%) for chronic bicarbonate and 6.0% (1.4 to 11.9%) for placebo. CONCLUSION: Performance in 2000-m rowing ergometer trials may not substantially improve after acute or chronic bicarbonate loading. However, performances will be reliable with both acute and chronic bicarbonate loading protocols.