International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them. The daily recommended intake (DRI) for protein was established to prevent deficiencies due to inadequate EAA consumption. The following conclusions represent the official position of the Society: 1. Initial studies on EAAs' effects on skeletal muscle highlight their primary role in stimulating muscle protein synthesis (MPS) and turnover. Protein turnover is critical for replacing degraded or damaged muscle proteins, laying the metabolic foundation for enhanced functional performance. Consequently, research has shifted to examine the effects of EAA supplementation - with and without the benefits of exercise - on skeletal muscle maintenance and performance. 2. Supplementation with free-form EAAs leads to a quick rise in peripheral EAA concentrations, which in turn stimulates MPS. 3. The safe upper limit of EAA intake (amount), without inborn metabolic disease, can easily accommodate additional supplementation. 4. At rest, stimulation of MPS occurs at relatively small dosages (1.5-3.0 g) and seems to plateau at around 15-18 g. 5. The MPS stimulation by EAAs does not require non-essential amino acids. 6. Free-form EAA ingestion stimulates MPS more than an equivalent amount of intact protein. 7. Repeated EAA-induced MPS stimulation throughout the day does not diminish the anabolic effect of meal intake. 8. Although direct comparisons of various formulas have yet to be investigated, aging requires a greater proportion of leucine to overcome the reduced muscle sensitivity known as "anabolic resistance." 9. Without exercise, EAA supplementation can enhance functional outcomes in anabolic-resistant populations. 10. EAA requirements rise in the face of caloric deficits. During caloric deficit, it's essential to meet whole-body EAA requirements to preserve anabolic sensitivity in skeletal muscle.

Intermittent fasting and protein pacing are superior to caloric restriction for weight and visceral fat loss

OBJECTIVE

This study compared intermittent fasting and protein pacing (IF-P) versus a heart-healthy caloric restriction (CR) diet, matched for energy intake and physical activity energy expenditure, on body weight, total and visceral fat mass, and cardiometabolic health outcomes in adults with obesity.

METHODS

IF-P (n = 21) and CR (n = 20) were assessed pre- (week 0), mid- (week 5), and post- (week 9) intervention.

RESULTS

Both groups reduced (p < 0.05) weight, total and visceral fat mass, blood pressure and lipids, and desire to eat food and increased proportion of fat-free mass. IF-P resulted in greater (p < 0.05) reductions in weight (-9% vs. -5%), total (-16% vs. -9%) and visceral (-33% vs. -14%) fat mass, and desire to eat (-17% vs. 1%) and increased fat-free mass percent (6% vs. 3%) compared with CR. These improvements were despite similar weekly total energy intake (IF-P, 9470 ± 550 vs. CR, 9095 ± 608 kcal/wk; p = 0.90) and physical activity energy expenditure (IF-P, 300 ± 150 vs. CR, 350 ± 200 kcal/d; p = 0.79).

CONCLUSIONS

IF-P and CR optimize weight loss, body composition, cardiometabolic health, and hunger management, with IF-P providing greater benefits.

Exploratory analysis of one versus two-day intermittent fasting protocols on the gut microbiome and plasma metabolome in adults with overweight/obesity

Nutritional interventions are a promising therapeutic option for addressing obesity and cardiometabolic dysfunction. One such option, intermittent fasting (IF), has emerged as a viable alternative to daily caloric restriction and may beneficially modulate body weight regulation and alter the gut microbiome (GM) and plasma metabolome. This secondary analysis of a larger, registered trial (ClinicalTrials.gov ID: NCT04327141) examined the effect of a four-week intervention comparing one vs. two-consecutive days of IF in combination with protein pacing (IF-P; 4-5 meals/day, >30% protein/day) on the GM, the plasma metabolome, and associated clinical outcomes in overweight and obese adults. Participants (n = 20) were randomly assigned to either a diet consisting of one fasting day (total of 36 h) and six low-calorie P days per week (IF1-P, n = 10) or two fasting days (60 h total) and five low-calorie P days per week (IF2-P, n = 10). The fecal microbiome, clinical outcomes, and plasma metabolome were analyzed at baseline (week 0) and after four weeks. There were no significant time or interaction effects for alpha diversity; however, baseline alpha diversity was negatively correlated with percent body fat change after the four-week intervention (p = 0.030). In addition, beta-diversity for both IF groups was altered significantly by time (p = 0.001), with no significant differences between groups. The IF1-P group had a significant increase in abundance of Ruminococcaceae Incertae Sedis and Eubacterium fissicatena group (q ≤ 0.007), while the IF2-P group had a significant increase in abundance of Ruminococcaceae Incertae Sedis and a decrease in Eubacterium ventriosum group (q ≤ 0.005). The plasma metabolite profile of IF2-P participants displayed significant increases in serine, trimethylamine oxide (TMAO), levulinic acid, 3-aminobutyric acid, citrate, isocitrate, and glucuronic acid (q ≤ 0.049) compared to IF1-P. Fecal short-chain fatty acid concentrations did not differ significantly by time or between groups (p ≥ 0.126). Interestingly, gastrointestinal symptoms were significantly reduced for the IF2-P group but not for the IF1-P group. Our results demonstrate that short-term IF modestly influenced the GM community structure and the plasma metabolome, suggesting these protocols could be viable for certain nutritional intervention strategies.

Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men

The ideal exercise time of day (ETOD) remains elusive regarding simultaneous effects on health and performance outcomes, especially in women.

Purpose: Given known sex differences in response to exercise training, this study quantified health and performance outcomes in separate cohorts of women and men adhering to different ETOD.

Methods: Thirty exercise-trained women (BMI = 24 ± 3 kg/m²; 42 ± 8 years) and twenty-six men (BMI = 25.5 ± 3 kg/m²; 45 ± 8 years) were randomized to multimodal ETOD in the morning (0600–0800 h, AM) or evening (1830–2030 h, PM) for 12 weeks and analyzed as separate cohorts. Baseline (week 0) and post (week 12) muscular strength (1-RM bench/leg press), endurance (sit-ups/push-ups) and power (squat jumps, SJ; bench throws, BT), body composition (iDXA; fat mass, FM; abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange ratio (RER), profile of mood states (POMS), and dietary intake were assessed.

Results: Twenty-seven women and twenty men completed the 12-week intervention. No differences at baseline existed between groups (AM vs PM) for both women and men cohorts. In women, significant interactions (p < 0.05) existed for 1RM bench (8 ± 2 vs 12 ± 2, ∆kg), pushups (9 ± 1 vs 13 ± 2, ∆reps), BT (10 ± 6 vs 45 ± 28, ∆watts), SJ (135 ± 6 vs 39 ± 8, ∆watts), fat mass (−1.0 ± 0.2 vs −0.3 ± 0.2, ∆kg), Abfat (−2.6 ± 0.3 vs −0.9 ± 0.5, ∆kg), diastolic (−10 ± 1 vs−5 ± 5, ∆mmHg) and systolic (−12.5 ± 2.7 vs 2.3 ± 3, mmHg) BP, AM vs PM, respectively. In men, significant interactions (p < 0.05) existed for systolic BP (−3.5 ± 2.6 vs −14.9 ± 5.1, ∆mmHg), RER (−0.01 ± 0.01 vs −0.06 ± 0.01, ∆VCO₂/VO₂), and fatigue (−0.8 ± 2 vs −5.9 ± 2, ∆mm), AM vs PM, respectively. Macronutrient intake was similar among AM and PM groups.

Conclusion: Morning exercise (AM) reduced abdominal fat and blood pressure and evening exercise (PM) enhanced muscular performance in the women cohort. In the men cohort, PM increased fat oxidation and reduced systolic BP and fatigue. Thus, ETOD may be important to optimize individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.

Intermittent fasting two days versus one day per week, matched for total energy intake and expenditure, increases weight loss in overweight/obese men and women

Background

Intermittent fasting (IF), consisting of either a one-day (IF1) or two consecutive days (IF2) per week, is commonly used for optimal body weight loss. Our laboratory has previously shown an IF1 diet combined with 6d/week of protein pacing (P; 4–5 meals/day evenly spaced, ~ 30% protein/day) significantly enhances weight loss, body composition, and cardiometabolic health in obese men and women. Whether an IF1-P or IF2-P, matched for weekly energy intake (EI) and expenditure (EE), is superior for weight loss, body composition, and cardiometabolic health is unknown.

Methods

This randomized control study directly compared an IF1-P (n = 10) versus an IF2-P (n = 10) diet on weight loss and body composition, cardiovascular (blood pressure and lipids), hormone, and hunger responses in 20 overweight men and women during a 4-week weight loss period. Participants received weekly dietary counseling and monitoring of compliance from a registered dietitian. All outcome variables were assessed pre (week 0) and post (week 5).

Results

Both groups significantly reduced body weight, waist circumference, percent body fat, fat mass, hunger, blood pressure, lipids, glucose, and increased percent fat-free mass (p < 0.05). However, IF2-P resulted in significantly greater reductions in body weight (-29%) and waist circumference (-38%) compared to IF1-P (p < 0.05), and showed a strong tendency for greater reductions in fat mass, glucose, and hunger levels (p < 0.10) despite similar weekly total EI (IF1-P, 9058 ± 692 vs. IF2-P, 8389 ± 438 kcals/week; p = 0.90), EE (~ 300 kcals/day; p = 0.79), and hormone responses (p > 0.10).

Conclusions

These findings support short-term IF1-P and IF2-P to optimize weight loss and improve body composition, cardiometabolic health, and hunger management, with IF2-P providing enhanced benefits in overweight women and men.

Trial registration

This trial was registered March 03, 2020 at www.clinicaltrials.gov as NCT04327141.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-022-00790-0.

Resistant Starch Combined with Whey Protein Increases Postprandial Metabolism and Lowers Glucose and Insulin Responses in Healthy Adult Men

Resistant starch (RS) and/or protein consumption favorably influence energy metabolism, substrate utilization, and weight management. The current study administered four different versions of a pancake breakfast containing waxy maize or RS with and without whey protein (WP) and measured postprandial thermogenesis (TEM), fuel utilization, and circulating satiation and appetite factors for 180 min in a group of healthy, adult men. On four separate visits to the laboratory, eight participants were administered four different pancake breakfast meal challenges using a single-blind, randomized crossover design: (1) waxy maize starch (WMS) control; (2) WMS and WP (WMS + WP); (3) RS; or (4) RS and WP (RS + WP). TEM (kcals/180 min) was significantly greater (p < 0.05) in RS + WP (45.11; confidence interval (CI), 33.81–56.41) compared to WMS (25.61; CI, 14.31–36.91), RS (29.44; CI, 18.14–40.74), and WMS + WP (24.64; CI, 13.34–35.94), respectively. Fat oxidation was enhanced (p < 0.05) after RS + WP compared to RS at 60 min (+23.10%), WMS at 120 min (+27.49%), and WMS and WMS + WP at 180 min (+35.76%; +17.31%, respectively), and RER was decreased with RS + WP versus the other three meals (mean differences: ≥−0.021). Insulin concentrations were decreased (p < 0.05) following RS + WP compared to WMS, whereas both RS (−46.19%) and RS + WP (−53.05%) insulin area under the curve (AUC) were greatly reduced (p < 0.01) compared to WMS. While limited by sample size, meals containing both RS and WP increased postprandial thermogenesis and fat oxidation, and lowered insulin response compared to isocaloric meals without this combination. Therefore, RS + WP may favorably impact energy metabolism and thus weight control and body composition under chronic feeding conditions.

Effects of Multi-ingredient Preworkout Supplements on Physical Performance, Cognitive Performance, Mood State, and Hormone Concentrations in Recreationally Active Men and Women

Beckner, ME, Pihoker, AA, Darnell, ME, Beals, K, Lovalekar, M, Proessl, F, Flanagan, SD, Arciero, PJ, Nindl, BC, and Martin, BJ. Effects of multi-ingredient preworkout supplements on physical performance, cognitive performance, mood state, and hormone concentrations in recreationally active men and women. J Strength Cond Res XX(X): 000-000, 2020-Performance enhancement supplement research has primarily focused on the effectiveness of individual ingredients, rather than the combination. This study investigated the acute effects of 2 multi-ingredient preworkout supplements (MIPS), with beta-alanine and caffeine (BAC) and without (NBAC), compared with placebo (PLA) on anaerobic performance, endurance capacity, mood state, cognitive function, vascular function, and anabolic hormones. Thirty exercise-trained individuals (24.4 ± 4.9 years, 15 men and 15 women) completed a fatiguing exercise protocol on 3 separate occasions, 30 minutes after ingestion of BAC, NBAC, or PLA. Outcomes were analyzed using one-way or two-way repeated-measures analysis of variance, as appropriate (alpha = 0.05). Anaerobic power was greater when supplementing with NBAC (10.7 ± 1.2 W·kg) and BAC (10.8 ± 1.4 W·kg) compared with PLA (10.4 ± 1.2 W·kg) (p = 0.014 and p = 0.022, respectively). BAC improved V[Combining Dot Above]O2peak time to exhaustion (p = 0.006), accompanied by an increase in blood lactate accumulation (p < 0.001), compared with PLA. Both NBAC and BAC demonstrated improved brachial artery diameter after workout (p = 0.041 and p = 0.005, respectively), but PLA did not. L-arginine concentrations increased from baseline to postsupplement consumption of BAC (p = 0.017). Reaction time significantly decreased after exercise for all supplements. There was no effect of supplement on mood states. Exercise-trained individuals looking to achieve modest improvements in power and endurance may benefit from consuming MIPS before exercise.

The athletic gut microbiota

The microorganisms in the gastrointestinal tract play a significant role in nutrient uptake, vitamin synthesis, energy harvest, inflammatory modulation, and host immune response, collectively contributing to human health. Important factors such as age, birth method, antibiotic use, and diet have been established as formative factors that shape the gut microbiota. Yet, less described is the role that exercise plays, particularly how associated factors and stressors, such as sport/exercise-specific diet, environment, and their interactions, may influence the gut microbiota. In particular, high-level athletes offer remarkable physiology and metabolism (including muscular strength/power, aerobic capacity, energy expenditure, and heat production) compared to sedentary individuals, and provide unique insight in gut microbiota research. In addition, the gut microbiota with its ability to harvest energy, modulate the immune system, and influence gastrointestinal health, likely plays an important role in athlete health, wellbeing, and sports performance. Therefore, understanding the mechanisms in which the gut microbiota could play in the role of influencing athletic performance is of considerable interest to athletes who work to improve their results in competition as well as reduce recovery time during training. Ultimately this research is expected to extend beyond athletics as understanding optimal fitness has applications for overall health and wellness in larger communities. Therefore, the purpose of this narrative review is to summarize current knowledge of the athletic gut microbiota and the factors that shape it. Exercise, associated dietary factors, and the athletic classification promote a more “health-associated” gut microbiota. Such features include a higher abundance of health-promoting bacterial species, increased microbial diversity, functional metabolic capacity, and microbial-associated metabolites, stimulation of bacterial abundance that can modulate mucosal immunity, and improved gastrointestinal barrier function.

Higher-protein intake and physical activity are associated with healthier body composition and cardiometabolic health in Hispanic adults

BACKGROUND

Higher protein (HP) intake and physical activity (PA) have been associated with improved lean soft tissue (LST) and reduced fat mass (FM). Puerto Ricans have among the highest age-adjusted prevalence (42.5%) of obesity, which may be associated with inadequate protein consumption and PA. We examined the relationship between protein intake and PA with body composition and biomarkers of cardiometabolic health in Puerto Rican adults.

METHODS

Participants included 959 Puerto Rican adults (71.4% women, 28.6% men) from the Boston Puerto Rican Health Study (BPRHS), aged 46-79 y (Women: age, 60.4 ± 7.6 y, BMI, 32.9 ± 6.8 kg/m2; Men: age, 59.8 ± 7.9 y, BMI, 30.1 ± 5.2 kg/m2). Protein intake was assessed using a food frequency questionnaire and expressed as g/kg body weight/day in energy intake-adjusted equal cut point tertile categories (lower, moderate, higher: LP < 0.91 g/kg/d, MP ≥ 0.91 ≤ 1.11 g/kg/d, and HP > 1.11 g/kg/d). PA was assessed by questionnaire and expressed in tertile categories (low, moderate and high; PA1: <0.8 km/d, PA2: ≥0.8  ≤ 3.2 km/d, PA3: >3.2 km/d).

RESULTS

Participants with energy-adjusted HP had lower appendicular LST (ALST: 16.2 ± 3.8 kg), LST (39.7 ± 8.0 kg) and FM (25.6 ± 8.1 kg) when compared to LP (ALST: 20.1 ± 4.5 kg; LST: 49.5 ± 10.0 kg; FM: 40.8 ± 12.3 kg; P < 0.001) and MP (ALST: 18.2 ± 4.3 kg; LST: 44.1 ± 8.8 kg; FM: 32.2 ± 9.8 kg; P < 0.001). However, when adjusted for total body weight (kg), relative LST was significantly greater in HP (58 ± 9%) when compared to LP (53 ± 9%; P < 0.001) and MP (56 ± 9%; P < 0.001). Participants in PA3 had greater ALST (19.5 ± 5.4 kg), and LST (58 ± 10%), compared to PA1 (ALST: 17.2 ± 4.3 kg; LST: 53 ± 9%; P < 0.001) or PA2 (ALST: 17.7 ± 4.7 kg; LST: 56 ± 9%; P < 0.05). Those in HP + PA3 or MP + PA2 had lower c-reactive protein (CRP; HP + PA3: 5.1 ± 6.8 mg/L; MP + PA2: 6.4 ± 10.0 mg/L), when compared to LP + PA1 (8.7 ± 8.8 mg/L; P < 0.05). Insulin concentration was lower for those in both the HP and PA3 (HP + PA3; 11.4 ± 7.9 IU/mL) compared to those in both the LP and PA1 (LP + PA1; 20.7 ± 16.3 UI/mL) (P < 0.001).

CONCLUSIONS

The highest tertiles of energy-adjusted protein intake (≥1.11 g/kg/d) and PA (>3.2 km/d) were associated with more desirable indicators of overall body composition and cardiometabolic health, when adjusted for body weight, than those in the lower protein intake and PA in Puerto Rican adults.

The Enhanced Interactive Physical and Cognitive Exercise System (iPACESTM v2.0): Pilot Clinical Trial of an In-Home iPad-Based Neuro-Exergame for Mild Cognitive Impairment (MCI)

Given increasing longevity worldwide, older adults and caregivers are seeking ways to curb cognitive decline especially for those with mild cognitive impairment (MCI, now mild neurocognitive disorder, mNCD, Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-V). This quasi-experimental, within-subjects pilot clinical trial was designed to replicate and extend the study of cognitive benefits for MCI by improving upon our prior interactive Physical and Cognitive Exercise Study (iPACESTM v1.0) by increasing the usability of the neuro-exergame and exploring possible underlying neurobiological mechanisms. Older adults were enrolled in a three-month, in-home trial of a portable neuro-exergame (iPACES™ v2.0) where participants pedaled and steered along a virtual bike path (Memory Lane™). Neuropsychological function was assessed at baseline after component familiarization intervals (e.g., two weeks of exercise-only, game-only, etc.) and after three months of interactive neuro-exergame intervention. Fourteen participants were enrolled in the study and seven completed the final evaluation. Intent-to-treat analyses were conducted with imputed missing data (total n = 14). Significant improvement in executive function (Stroop) was found (d = 0.68, p = 0.02) only. Changes in salivary biomarkers (cortisol and insulin-like growth factor 1; IGF-1) were significantly associated with improved cognition. Further research is needed, but pilot data suggest that a portable in-home neuro-exergame may be an additional, practical tool to fight back against cognitive decline and dementia.

The Aerobic and Cognitive Exercise Study (ACES) for Community-Dwelling Older Adults With or At-Risk for Mild Cognitive Impairment (MCI): Neuropsychological, Neurobiological and Neuroimaging Outcomes of a Randomized Clinical Trial

Prior research has found that cognitive benefits of physical exercise and brain health in older adults may be enhanced when mental exercise is interactive simultaneously, as in exergaming. It is unclear whether the cognitive benefit can be maximized by increasing the degree of mental challenge during exercise. This randomized clinical trial (RCT), the Aerobic and Cognitive Exercise Study (ACES) sought to replicate and extend prior findings of added cognitive benefit from exergaming to those with or at risk for mild cognitive impairment (MCI). ACES compares the effects of 6 months of an exer-tour (virtual reality bike rides) with the effects of a more effortful exer-score (pedaling through a videogame to score points). Fourteen community-dwelling older adults meeting screening criteria for MCI (sMCI) were adherent to their assigned exercise for 6 months. The primary outcome was executive function, while secondary outcomes included memory and everyday cognitive function. Exer-tour and exer-score yielded significant moderate effects on executive function (Stroop A/C; d's = 0.51 and 0.47); there was no significant interaction effect. However, after 3 months the exer-tour revealed a significant and moderate effect, while exer-score showed little impact, as did a game-only condition. Both exer-tour and exer-score conditions also resulted in significant improvements in verbal memory. Effects appear to generalize to self-reported everyday cognitive function. Pilot data, including salivary biomarkers and structural MRI, were gathered at baseline and 6 months; exercise dose was associated with increased BDNF as well as increased gray matter volume in the PFC and ACC. Improvement in memory was associated with an increase in the DLPFC. Improved executive function was associated with increased expression of exosomal miRNA-9. Interactive physical and cognitive exercise (both high and low mental challenge) yielded similarly significant cognitive benefit for adherent sMCI exercisers over 6 months. A larger RCT is needed to confirm these findings. Further innovation and clinical trial data are needed to develop accessible, yet engaging and effective interventions to combat cognitive decline for the growing MCI population.

ClinicalTrials.gov ID: NCT02237560

International society of sports nutrition position stand: nutrient timing

The International Society of Sports Nutrition (ISSN) provides an objective and critical review regarding the timing of macronutrients in reference to healthy, exercising adults and in particular highly trained individuals on exercise performance and body composition. The following points summarize the position of the ISSN:

Nutrient timing incorporates the use of methodical planning and eating of whole foods, fortified foods and dietary supplements. The timing of energy intake and the ratio of certain ingested macronutrients may enhance recovery and tissue repair, augment muscle protein synthesis (MPS), and improve mood states following high-volume or intense exercise.

Endogenous glycogen stores are maximized by following a high-carbohydrate diet (8–12 g of carbohydrate/kg/day [g/kg/day]); moreover, these stores are depleted most by high volume exercise.

If rapid restoration of glycogen is required (< 4 h of recovery time) then the following strategies should be considered:

aggressive carbohydrate refeeding (1.2 g/kg/h) with a preference towards carbohydrate sources that have a high (> 70) glycemic index

the addition of caffeine (3–8 mg/kg)

combining carbohydrates (0.8 g/kg/h) with protein (0.2–0.4 g/kg/h)

Extended (> 60 min) bouts of high intensity (> 70% VO₂max) exercise challenge fuel supply and fluid regulation, thus carbohydrate should be consumed at a rate of ~30–60 g of carbohydrate/h in a 6–8% carbohydrate-electrolyte solution (6–12 fluid ounces) every 10–15 min throughout the entire exercise bout, particularly in those exercise bouts that span beyond 70 min. When carbohydrate delivery is inadequate, adding protein may help increase performance, ameliorate muscle damage, promote euglycemia and facilitate glycogen re-synthesis.

Carbohydrate ingestion throughout resistance exercise (e.g., 3–6 sets of 8–12 repetition maximum [RM] using multiple exercises targeting all major muscle groups) has been shown to promote euglycemia and higher glycogen stores. Consuming carbohydrate solely or in combination with protein during resistance exercise increases muscle glycogen stores, ameliorates muscle damage, and facilitates greater acute and chronic training adaptations.

Meeting the total daily intake of protein, preferably with evenly spaced protein feedings (approximately every 3 h during the day), should be viewed as a primary area of emphasis for exercising individuals.

Ingestion of essential amino acids (EAA; approximately 10 g)either in free form or as part of a protein bolus of approximately 20–40 g has been shown to maximally stimulate muscle protein synthesis (MPS).

Pre- and/or post-exercise nutritional interventions (carbohydrate + protein or protein alone) may operate as an effective strategy to support increases in strength and improvements in body composition. However, the size and timing of a pre-exercise meal may impact the extent to which post-exercise protein feeding is required.

Post-exercise ingestion (immediately to 2-h post) of high-quality protein sources stimulates robust increases in MPS.

In non-exercising scenarios, changing the frequency of meals has shown limited impact on weight loss and body composition, with stronger evidence to indicate meal frequency can favorably improve appetite and satiety. More research is needed to determine the influence of combining an exercise program with altered meal frequencies on weight loss and body composition with preliminary research indicating a potential benefit.

Ingesting a 20–40 g protein dose (0.25–0.40 g/kg body mass/dose) of a high-quality source every three to 4 h appears to most favorably affect MPS rates when compared to other dietary patterns and is associated with improved body composition and performance outcomes.

Consuming casein protein (~ 30–40 g) prior to sleep can acutely increase MPS and metabolic rate throughout the night without influencing lipolysis.

Effects of a combined protein and antioxidant supplement on recovery of muscle function and soreness following eccentric exercise

BACKGROUND

An acute bout of eccentric contractions (ECC) cause muscle fiber damage, inflammation, impaired muscle function (MF) and muscle soreness (MS). Individually, protein (PRO) and antioxidant (AO) supplementation may improve some aspects of recovery from ECC, though have yet to be combined. We sought to determine if combined PRO and AO supplementation (PRO + AO) improves MS and MF following damaging ECC over PRO alone.

METHODS

Sixty sedentary college-aged males participated in a randomized, single-blind, parallel design study of peak isometric torque (PIMT), peak isokinetic torque (PIKT), thigh circumference (TC), and muscle soreness (MS) of knee extensor muscles measured at baseline, immediately after and 1, 2, 6, and 24 h after completion of 100 maximal ECC. Immediately, 6 h, and 22 h post-ECC, participants consumed either: carbohydrate control (CHO; n = 14), PRO (n = 16), or PRO + AO (n = 17).

RESULTS

At baseline MS, TC, MF, macro- and micro-nutrient intakes, and total work during the ECC were not different between groups (p > 0.05). PIMT and PIKT (both -25%∆), TC (~1%∆) and MS (~35%∆) all changed with time (p < 0.05). We observed a group by time effect for PIKT (PRO + AO and PRO > CHO, p < 0.05). At 24 h post ECC, there was a trend towards improved relative PIMT (~11%) and PIKT (~17%) for PRO + AO (~17%) and PRO (~11%) compared to CHO. An interaction indicated PRO + AO had lowest MS over time (PRO + AO > PRO & CHO, p < 0.05).

CONCLUSIONS

Our results suggest PRO facilitates recovery of muscle function within 24 h following ECC, and addition of AO ameliorates MS more than PRO or CHO alone.

International Society of Sports Nutrition Position Stand: protein and exercise

The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows:An acute exercise stimulus, particularly resistance exercise, and protein ingestion both stimulate muscle protein synthesis (MPS) and are synergistic when protein consumption occurs before or after resistance exercise.For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4-2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein.Higher protein intakes (2.3-3.1 g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods.There is novel evidence that suggests higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass).Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli. General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20-40 g.Acute protein doses should strive to contain 700-3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs).These protein doses should ideally be evenly distributed, every 3-4 h, across the day.The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 h), but likely diminishes with increasing time post-exercise.While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training. Rapidly digested proteins that contain high proportions of essential amino acids (EAAs) and adequate leucine, are most effective in stimulating MPS. Different types and quality of protein can affect amino acid bioavailability following protein supplementation. Athletes should consider focusing on whole food sources of protein that contain all of the EAAs (i.e., it is the EAAs that are required to stimulate MPS). Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery. Pre-sleep casein protein intake (30-40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis.

International society of sports nutrition position stand: diets and body composition

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of diet types (macronutrient composition; eating styles) and their influence on body composition. The ISSN has concluded the following. 1) There is a multitude of diet types and eating styles, whereby numerous subtypes fall under each major dietary archetype. 2) All body composition assessment methods have strengths and limitations. 3) Diets primarily focused on fat loss are driven by a sustained caloric deficit. The higher the baseline body fat level, the more aggressively the caloric deficit may be imposed. Slower rates of weight loss can better preserve lean mass (LM) in leaner subjects. 4) Diets focused primarily on accruing LM are driven by a sustained caloric surplus to facilitate anabolic processes and support increasing resistance-training demands. The composition and magnitude of the surplus, as well as training status of the subjects can influence the nature of the gains. 5) A wide range of dietary approaches (low-fat to low-carbohydrate/ketogenic, and all points between) can be similarly effective for improving body composition. 6) Increasing dietary protein to levels significantly beyond current recommendations for athletic populations may result in improved body composition. Higher protein intakes (2.3–3.1 g/kg FFM) may be required to maximize muscle retention in lean, resistance-trained subjects under hypocaloric conditions. Emerging research on very high protein intakes (>3 g/kg) has demonstrated that the known thermic, satiating, and LM-preserving effects of dietary protein might be amplified in resistance-training subjects. 7) The collective body of intermittent caloric restriction research demonstrates no significant advantage over daily caloric restriction for improving body composition. 8) The long-term success of a diet depends upon compliance and suppression or circumvention of mitigating factors such as adaptive thermogenesis. 9) There is a paucity of research on women and older populations, as well as a wide range of untapped permutations of feeding frequency and macronutrient distribution at various energetic balances combined with training. Behavioral and lifestyle modification strategies are still poorly researched areas of weight management.

Multi-modal exercise training and protein-pacing enhances physical performance adaptations independent of growth hormone and BDNF but may be dependent on IGF-1 in exercise-trained men

OBJECTIVE

Protein-pacing (P; 5-6meals/day @ 2.0g/kgBW/day) and multi-mode exercise (RISE; resistance, interval, stretching, endurance) training (PRISE) improves muscular endurance, strength, power and arterial health in exercise-trained women. The current study extends these findings by examining PRISE on fitness, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and brain-derived neurotrophic factor (BDNF) response, cardiometabolic health, and body composition in exercise-trained men.

DESIGN

Twenty active males (>4daysexercise/week) completed either: PRISE (n=11) or RISE (5-6meals/day @ 1.0g/kgBW/day; n=9) for 12weeks. Muscular strength (1-repetition maximum bench and leg press, 1-RM BP, and 1-RM LP), endurance (sit-ups, SU; push-ups, PU), power (squat jump, SJ, and bench throw, BT), flexibility (sit-and-reach, SR), aerobic performance (5km cycling time-trial, TT), GH, IGF-1, BDNF, augmentation index, (AIx), and body composition, were assessed at weeks 0 (pre) and 13 (post).

RESULTS

At baseline, no differences existed between groups except for GH (RISE, 230±13 vs. PRISE, 382±59pg/ml, p<0.05). The exercise intervention improved 1-RM, SJ, BT, PU, SU, SR, 5km-TT, GH, AIx, BP, and body composition in both groups (time, p<0.05). However, PRISE elicited greater improvements in 1-RM BP (21 vs. 10∆lbs), SJ (171 vs. 13∆W), 5km-TT (-37 vs. -11∆s), and sit-and-reach (5.3 vs. 1.2∆cm) over RISE alone (p<0.05) including increased IGF-1 (12%, p<0.05).

CONCLUSIONS

Exercise-trained men consuming a P diet combined with multi-component exercise training (PRISE) enhance muscular power, strength, aerobic performance, and flexibility which are not likely related to GH or BDNF but possibly to IGF-1 response.

Serum Polychlorinated Biphenyls Increase and Oxidative Stress Decreases with a Protein-Pacing Caloric Restriction Diet in Obese Men and Women

The purposes were to compare the effects of a: (1) 12-week P-CR weight loss (WL) diet (Phase 1) between obese men and women and; (2) 52-week modified P-CR (mP-CR) vs. heart healthy (HH) weight maintenance (WM) diet (Phase 2) on serum PCBs and oxidative stress biomarkers (thiobarbituric acid reactive substances, TBARS; total antioxidant capacity, TAC) in 40 obese participants (men, n = 21; women, n = 19). Participants received dietary counseling and monitoring of compliance. PCBs, TBARS, and TAC were assessed at weeks -1 (CON), 12 (WL), and 64 (WM). Following WL (Week 12), concomitant with reductions in TBARS (0.24 ± 0.15 vs. 0.18 ± 0.11 µM; p < 0.01), PCB serum concentrations (86.7 ± 45.6 vs. 115.6 ± 65.9 ng/g lipid; p < 0.01) and TAC (18.9 ± 2.6 vs. 19.9 ± 2.3 nmol/mL; p < 0.02) were increased similarly in men and women. At the end of WM (Week 64), a significant effect of time × group interaction was observed for % change in PCB 170 and 187; whereby mP-CR values were higher compared to HH (PCB170: 19.31% ± 26.48% vs. -6.61% ± 28.88%, p = 0.02; PCB187: -3.04% ± 17.78% vs. -21.4% ± 27.31%, p = 0.04). PCB changes were positively correlated with TBARS levels (r > 0.42, p < 0.05) and negatively correlated with body weight, fat mass, and abdominal fat (r < -0.46, p < 0.02). Our results support mobilization of stored PCBs as well as enhanced redox status following a 12-week P-CR WL diet. Additionally, a 52-week mP-CR WM diet demonstrated an advantage in preventing weight gain relapse accompanied by an increase in circulating PCBs compared to a traditional HH diet.

Comparison of High-Protein, Intermittent Fasting Low-Calorie Diet and Heart Healthy Diet for Vascular Health of the Obese

AIM

It has been debated whether different diets are more or less effective in long-term weight loss success and cardiovascular disease prevention among men and women. To further explore these questions, the present study evaluated the combined effects of a high-protein, intermittent fasting, low-calorie diet plan compared with a heart healthy diet plan during weight loss, and weight loss maintenance on blood lipids and vascular compliance of obese individuals.

METHODS

The experiment involved 40 obese adults (men, n = 21; women, n = 19) and was divided into two phases: (a) 12-week high-protein, intermittent fasting, low-calorie weight loss diet comparing men and women (Phase 1) and (b) a 1-year weight maintenance phase comparing high-protein, intermittent fasting with a heart healthy diet (Phase 2). Body weight, body mass index (BMI), blood lipids, and arterial compliance outcomes were assessed at weeks 1 (baseline control), 12 (weight loss), and 64 (12 + 52 week; weight loss maintenance).

RESULTS

At the end of weight loss intervention, concomitant reductions in body weight, BMI and blood lipids were observed, as well as enhanced arterial compliance. No sex-specific differences in responses were observed. During phase 2, the high-protein, intermittent fasting group demonstrated a trend for less regain in BMI, low-density lipoprotein (LDL), and aortic pulse wave velocity than the heart healthy group.

CONCLUSION

Our results suggest that a high-protein, intermittent fasting and low-calorie diet is associated with similar reductions in BMI and blood lipids in obese men and women. This diet also demonstrated an advantage in minimizing weight regain as well as enhancing arterial compliance as compared to a heart healthy diet after 1 year.

Protein-Pacing Caloric-Restriction Enhances Body Composition Similarly in Obese Men and Women during Weight Loss and Sustains Efficacy during Long-Term Weight Maintenance

Short-Term protein-pacing (P; ~6 meals/day, >30% protein/day) and caloric restriction (CR, ~25% energy deficit) improves total (TBF), abdominal (ABF) and visceral (VAT) fat loss, energy expenditure, and biomarkers compared to heart healthy (HH) recommendations (3 meals/day, 15% protein/day) in obese adults. Less is known whether obese men and women respond similarly to P-CR during weight loss (WL) and whether a modified P-CR (mP-CR) is more efficacious than a HH diet during long-term (52 week) weight maintenance (WM). The purposes of this study were to evaluate the efficacy of: (1) P-CR on TBF, ABF, resting metabolic rate (RMR), and biomarkers between obese men and women during WL (weeks 0–12); and (2) mP-CR compared to a HH diet during WM (weeks 13–64). During WL, men (n = 21) and women (n = 19) were assessed for TBF, ABF, VAT, RMR, and biomarkers at weeks 0 (pre) and 12 (post). Men and women had similar reductions (p < 0.01) in weight (10%), TBF (19%), ABF (25%), VAT (33%), glucose (7%–12%), insulin (40%), leptin (>50%) and increase in % lean body mass (9%). RMR (kcals/kg bodyweight) was unchanged and respiratory quotient decreased 9%. Twenty-four subjects (mP-CR, n = 10; HH, n = 14) completed WM. mP-CR regained significantly less body weight (6%), TBF (12%), and ABF (17%) compared to HH (p < 0.05). Our results demonstrate P-CR enhances weight loss, body composition and biomarkers, and maintains these changes for 52-weeks compared to a traditional HH diet.

The influence of nighttime feeding of carbohydrate or protein combined with exercise training on appetite and cardiometabolic risk in young obese women

Single macronutrient intake prior to sleep reduces appetite but may negatively impact insulin sensitivity in sedentary obese women. The present study examined the additive impact of nighttime feeding of whey (WH), casein (CAS), or carbohydrate (CHO) combined with exercise training on appetite, cardiometabolic health, and strength in obese women. Thirty-seven sedentary obese women (WH, n = 13, body mass index (BMI) 34.4 ± 1.3 kg/m(2); CAS, n = 14, BMI 36.5 ± 1.8 kg/m(2); CHO, n = 10, BMI 33.1 ± 1.7 kg/m(2)) consumed WH, CAS, or CHO (140-150 kcal/serving), every night of the week, within 30 min of sleep, for 4 weeks. Supervised exercise training (2 days of resistance training and 1 day of high-intensity interval training) was completed 3 days per week. Pre- and post-testing measurements included appetite ratings, mood state, resting metabolic rate, fasting lipids, glucose, and hormonal responses (insulin, leptin, adiponectin, hs-CRP, IGF-1, and cortisol), body composition, and strength. Nighttime intake of CAS significantly (p < 0.05) increased morning satiety (pretraining, 25 ± 5; post-training 41 ± 6) more than WH (pretraining, 34 ± 5; post-training, 35 ± 6) or CHO (pre 40 ± 8, post 43 ± 7). Exercise training increased lean mass and strength, decreased body fat, and improved mood state in all groups. No other differences were noted. Nighttime feeding of CAS combined with exercise training increased morning satiety more than WH or CHO. Nighttime feeding for 4 weeks did not impact insulin sensitivity (assessed via homeostatic model assessment of insulin resistance) when combined with exercise training in obese women. ClinicalTrial.gov: NCT01830946.

Protein-Pacing from Food or Supplementation Improves Physical Performance in Overweight Men and Women: The PRISE 2 Study

We recently reported that protein-pacing (P; six meals/day @ 1.4 g/kg body weight (BW), three of which included whey protein (WP) supplementation) combined with a multi-mode fitness program consisting of resistance, interval sprint, stretching, and endurance exercise training (RISE) improves body composition in overweight individuals. The purpose of this study was to extend these findings and determine whether protein-pacing with only food protein (FP) is comparable to WP supplementation during RISE training on physical performance outcomes in overweight/obese individuals. Thirty weight-matched volunteers were prescribed RISE training and a P diet derived from either whey protein supplementation (WP, n = 15) or food protein sources (FP, n = 15) for 16 weeks. Twenty-one participants completed the intervention (WP, n = 9; FP, n = 12). Measures of body composition and physical performance were significantly improved in both groups (p < 0.05), with no effect of protein source. Likewise, markers of cardiometabolic disease risk (e.g., LDL (low-density lipoprotein) cholesterol, glucose, insulin, adiponectin, systolic blood pressure) were significantly improved (p < 0.05) to a similar extent in both groups. These results demonstrate that both whey protein and food protein sources combined with multimodal RISE training are equally effective at improving physical performance and cardiometabolic health in obese individuals.

Resistant starch and protein intake enhances fat oxidation and feelings of fullness in lean and overweight/obese women

Background

Diets high in either resistant starch or protein have been shown to aid in weight management. We examined the effects of meals high in non-resistant or resistant starch with and without elevated protein intake on substrate utilization, energy expenditure, and satiety in lean and overweight/obese women.

Methods

Women of varying levels of adiposity consumed one of four pancake test meals in a single-blind, randomized crossover design: 1) waxy maize (control) starch (WMS); 2) waxy maize starch and whey protein (WMS+WP); 3) resistant starch (RS); or 4) RS and whey protein (RS+WP).

Results

Total post-prandial energy expenditure did not differ following any of the four test meals (WMS = 197.9 ± 8.9; WMS+WP = 188 ± 8.1; RS = 191.9 ± 8.9; RS+WP = 195.8 ± 8.7, kcals/180 min), although the combination of RS+WP, but not either intervention alone, significantly increased (P <0.01) fat oxidation (WMS = 89.5 ± 5.4; WMS+WP = 84.5 ± 7.2; RS = 97.4 ± 5.4; RS+WP = 107.8 ± 5.4, kcals/180 min). Measures of fullness increased (125 % vs. 45 %) and hunger decreased (55 % vs. 16 %) following WP supplemented versus non-whey conditions (WMS+WP, RS+WP vs. WMS, RS), whereas circulating hunger and satiety factors were not different among any of the test meals. However, peptide YY (PYY) was significantly elevated at 180 min following RS+WP meal.

Conclusions

The combined consumption of dietary resistant starch and protein increases fat oxidation, PYY, and enhances feelings of satiety and fullness to levels that may be clinically relevant if maintained under chronic conditions. This trial was registered at clinicaltrials.gov as NCT02418429.

The impact of a pre-loaded multi-ingredient performance supplement on muscle soreness and performance following downhill running

The effects of multi-ingredient performance supplements (MIPS) on perceived soreness, strength, flexibility and vertical jump performance following eccentric exercise are unknown. The purpose of this study was to determine the impact of MIPS (NO-Shotgun®) pre-loaded 4 weeks prior to a single bout of downhill running (DHR) on muscle soreness and performance. Trained male runners (n = 20) were stratified by VO_2max, strength, and lean mass into two groups; MIPS (n = 10) ingested one serving daily of NO-Shotgun® for 28 days and 30 min prior to all post-testing visits, Control (CON; n = 10) consumed an isocaloric maltodextrin placebo in an identical manner as MIPS. Perceived soreness and performance measurements (strength, flexibility, and jump height) were tested on 6 occasions; 28 days prior to DHR, immediately before DHR (PRE), immediately post (POST) DHR, 24, 48, and 72 hr post-DHR. Perceived soreness significantly increased (p < 0.05) post DHR compared to PRE at all time-points, with no difference between groups. Creatine kinase (CK) and lactate dehydrogenase (LDH) increased over time (p < 0.001) with no group x time interactions (p = 0.236 and p = 0.535, respectively). Significant time effects were measured for strength (p = 0.001), flexibility (p = 0.025) and vertical jump (p < 0.001). There were no group x time interactions for any performance measurements. Consumption of MIPS for 4 weeks prior to a single bout of DHR did not affect perceived soreness, muscle damage, strength, flexibility, or jump performance compared to an isocaloric placebo in trained male runners following a single bout of DHR.

Executive function and self-regulated exergaming adherence among older adults

The rise in dementia and the evidence of cognitive benefits of exercise for the older adult population together make salient the research into variables affecting cognitive benefit and exercise behavior. One promising avenue for increasing exercise participation has been the introduction of exergaming, a type of exercise that works in combination with virtual reality to enhance both the exercise experience and health outcomes. Past research has revealed that executive function (EF) was related to greater use of self-regulatory strategies, which in turn was related to greater adherence to exercise following an intervention (McAuley et al., 2011). Best et al. (2014) found improvement in EF related to adherence to exercise post- intervention. Anderson-Hanley et al. (2012) found that for older adults aerobic exergaming yielded greater cognitive benefit than traditional exercise alone; however, questions remain as to the possible impact of greater cognitive benefit and other factors on participants’ involvement in exercise following the end of an intervention. The current study presents follow-up data exploring the relationship between EF, self-regulation, and exercise behavior in the post-intervention (naturalistic) period. Herein, it was predicted that higher EF at the start of the naturalistic window, would predict subsequent exercise with an exergame. Contrary to expectations, results suggest that those with poorer EF are likely to exergame more frequently. The results of this study contradict previous literature, but suggest an interesting relationship between EF, self-regulation, and exercise behaviors when exergaming is employed, particularly with older adults with some cognitive decline. We hypothesize that other factors may be at work, perhaps expectation of cognitive benefit might act as a unique motivator.

Timed-daily ingestion of whey protein and exercise training reduces visceral adipose tissue mass and improves insulin resistance: the PRISE study

The present study examined the effects of timed ingestion of supplemental protein (20-g servings of whey protein, 3×/day), added to the habitual diet of free-living overweight/obese adults and subsequently randomized to either whey protein only (P; n = 24), whey protein and resistance exercise (P + RT; n = 27), or a whey protein and multimode exercise training program [protein and resistance exercise, intervals, stretching/yoga/Pilates, endurance exercise (PRISE); n = 28]. Total and regional body composition and visceral adipose tissue (VAT) mass (dual-energy X-ray absorptiometry), insulin sensitivity [homeostasis model assessment-estimated insulin resistance (HOMA-IR)], plasma lipids and adipokines, and feelings of hunger and satiety (visual analog scales) were measured before and after the 16-wk intervention. All groups lost body weight, fat mass (FM), and abdominal fat; however, PRISE lost significantly (P < 0.01) more body weight (3.3 ± 0.7 vs. 1.1 ± 0.7 kg, P + RT) and FM (2.8 ± 0.7 vs. 0.9 ± 0.5 kg, P + RT) and gained (P < 0.05) a greater percentage of lean body mass (2 ± 0.5 vs. 0.9 ± 0.3 and 0.6 ± 0.4%, P + RT and P, respectively). Only P + RT (0.1 ± 0.04 kg) and PRISE (0.21 ± 0.07 kg) lost VAT mass (P < 0.05). Fasting glucose decreased only in P + RT (5.1 ± 2.5 mg/dl) and PRISE (15.3 ± 2.1 mg/dl), with the greatest decline occurring in PRISE (P < 0.05). Similarly, HOMA-IR improved (0.6 ± 0.3, 0.6 ± 0.4 units), and leptin decreased (4.7 ± 2.2, 4.7 ± 3.1 ng/dl), and adiponectin increased (3.8 ± 1.1, 2.4 ± 1.1 μg/ml) only in P + RT and PRISE, respectively, with no change in P. In conclusion, we find evidence to support exercise training and timed ingestion of whey protein added to the habitual diet of free-living overweight/obese adults, independent of caloric restriction on total and regional body fat distribution, insulin resistance, and adipokines.

Increased protein intake and meal frequency reduces abdominal fat during energy balance and energy deficit

OBJECTIVE

Unrefined, complex carbohydrates and lean protein diets are used to combat obesity, although it's unknown whether more frequent meals may improve this response. The effects of consuming traditional (~15%) versus higher (~35%) protein intakes as three or six meals/day on abdominal fat, postprandial thermogenesis (TEM), and cardiometabolic biomarkers in overweight individuals during 28 days of energy balance (BAL) and deficit (NEG), respectively were compared.

DESIGN AND METHODS

Overweight individuals (n = 30) were randomized into three groups: two high-protein groups (35% of energy) consumed as three (HP3) or six (HP6) meals/day and one group consumed three meals/day of a traditional intake (TD3). Following a 5-day baseline control (CON), subjects consumed their respective diets throughout a 56-day intervention consisting of two, 28 day phases: a BAL followed by a NEG phase (75% of energy needs). Total body fat (BF) and abdominal BF (ABF), body weight (BW), TEM, and fasting biomarkers were assessed at the end of CON, BAL, and NEG phases.

RESULTS

BW remained stable throughout CON and BAL in all groups, whereas BF (P < 0.001) and ABF (P < 0.01) decreased in HP groups and lean body mass (LBM) and leptin increased in HP6. Following NEG, BW decreased in all groups. BF, ABF, and leptin decreased in HP groups; LBM remained higher (P < 0.05), and TEM was highest in HP6 (P < 0.05).

CONCLUSIONS

Consuming increased protein (∼35%) more frequently (6×) throughout the day decreases BF and ABF, increases LBM and TEM, and favorably affects adipokines more than current recommendations for macronutrients consumed over three meals/day in overweight individuals during both BAL and NEG.

Detraining increases body fat and weight and decreases VO2peak and metabolic rate

Competitive collegiate swimmers commonly take a month off from swim training after their last major competition. This abrupt cessation of intense physical training has not been well studied and may lead to physiopsychological decline. The purpose of this investigation was to examine the effects of swim detraining (DT) on body composition, aerobic fitness, resting metabolism, mood state, and blood lipids in collegiate swimmers. Eight healthy endurance-trained swimmers (V(O2)peak, 46.7 ± 10.8 ml · kg(-1) · min(-1)) performed 2 identical test days, 1 in the trained (TR) state and 1 in the detrained (~5 weeks) state (DT). Body composition and circumferences, maximal oxygen consumption (V(O2)peak), resting metabolism (RMR), blood lipids, and mood state were measured. After DT, body weight (TR, 68.9 ± 9.7 vs. DT, 69.8 ± 9.8 kg; p = 0.03), fat mass (TR, 14.7 ± 7.6 vs. DT, 16.5 ± 7.4 kg; p = 0.001), and waist circumference (TR, 72.7 ± 3.1 vs. DT, 73.8 ± 3.6 cm; p = 0.03) increased, whereas V(O2)peak (TR, 46.7 ± 10.8 vs. DT, 43.1 ± 10.3 ml · kg(-1) · min(-1); p = 0.02) and RMR (TR, 1.34 ± 0.2 vs. DT, 1.25 ± 0.17 kcal · min(-1); p = 0.008) decreased, and plasma triglycerides showed a trend to increase (p = 0.065). Our data suggest that DT after a competitive collegiate swim season adversely affects body composition, fitness, and metabolism. Athletes and coaches need to be aware of the negative consequences of detraining from swimming, and plan off-season training schedules accordingly to allow for adequate rest/recovery and prevent overuse injuries. It's equally important to mitigate the negative effects on body composition, aerobic fitness and metabolism so performance may continue to improve over the long term.

Neuropsychological benefits of stationary bike exercise and a cybercycle exergame for older adults with diabetes: an exploratory analysis

OBJECTIVE

This quasi-experimental exploratory study investigated neuropsychological effects of exercise among older adults with diabetes mellitus (DM) compared with adults without diabetes (non-DM), and it examined the feasibility of using a stationary bike exergame as a form of exercise for older adults with and without diabetes. It is a secondary analysis that uses a small dataset from a larger randomized clinical trial (RCT) called the Cybercycle Study, which compared cognitive and physiological effects of traditional stationary cycling versus cybercycling.

METHODS

In the RCT and the secondary analysis, older adults living in eight independent living retirement facilities in the state of New York were enrolled in the study and assigned to exercise five times per week for 45 min per session (two times per week was considered acceptable for retention in the study) by using a stationary bicycle over the course of 3 months. They were randomly assigned to use either a standard stationary bicycle or a "cybercycle" with a video screen that displayed virtual terrains, virtual tours, and racing games with virtual competitors. For this secondary analysis, participants in the RCT who had type 2 DM (n = 10) were compared with age-matched non-DM exercisers (n = 10). The relationship between exercise and executive function (i.e., Color Trials 2, Digit Span Backwards, and Stroop C tests) was examined for DM and non-DM patients.

RESULTS

Older adults with and without diabetes were able to use cybercycles successfully and complete the study, so the feasibility of this form of exercise for this population was supported. However, in contrast with the larger RCT, this small subset did not demonstrate statistically significant differences in executive function between the participants who used cybercycles and those who used stationary bikes with no games or virtual content on a video screen. Therefore, the study combined the two groups and called them "exercisers" and compared cognitive outcomes for DM versus non-DM patients. As predicted, exercisers with DM exhibited significant gains in executive function as measured by the Color Trails 2 test, controlling for age and education, while non-DM exercisers did not significantly gain in this measure [group × time interaction, F(1,16]) = 9.75; p = .007].

CONCLUSIONS

These preliminary results support the growing literature that finds that exercise may improve cognition among older adult with DM. Additional research is needed to clarify why certain aspects of executive function might be differentially affected. The current findings may encourage physicians to prescribe exercise for diabetes management and may help motivate DM patients' compliance for engaging in physical activity.

Virtual and live social facilitation while exergaming: competitiveness moderates exercise intensity

Grounded in social facilitation theory, this study compared the impact on exercise intensity of a virtual versus a live competitor, when riding a virtual reality-enhanced stationary bike ("cybercycle"). It was hypothesized that competitiveness would moderate effects. Twenty-three female college students were exposed to three conditions on a cybercycle: solo training, virtual competitor, and live competitor. After training without a competitor (solo condition for familiarization with equipment), participants competed against a virtual avatar or live rider (random order of presentation). A repeated-measures analysis revealed a significant condition (virtual/live) by competitiveness (high/low) interaction for exercise intensity (watts). More competitive participants exhibited significantly greater exercise intensity when competing against a live versus virtual competitor. The implication is that live competitors can have an added social facilitation effect and influence exercise intensity, although competitiveness moderates this effect.

Exergaming and older adult cognition: a cluster randomized clinical trial

BACKGROUND

Dementia cases may reach 100 million by 2050. Interventions are sought to curb or prevent cognitive decline. Exercise yields cognitive benefits, but few older adults exercise. Virtual reality-enhanced exercise or "exergames" may elicit greater participation.

PURPOSE

To test the following hypotheses: (1) stationary cycling with virtual reality tours ("cybercycle") will enhance executive function and clinical status more than traditional exercise; (2) exercise effort will explain improvement; and (3) brain-derived neurotrophic growth factor (BDNF) will increase.

DESIGN

Multi-site cluster randomized clinical trial (RCT) of the impact of 3 months of cybercycling versus traditional exercise, on cognitive function in older adults. Data were collected in 2008-2010; analyses were conducted in 2010-2011.

SETTING/PARTICIPANTS

102 older adults from eight retirement communities enrolled; 79 were randomized and 63 completed.

INTERVENTIONS

A recumbent stationary ergometer was utilized; virtual reality tours and competitors were enabled on the cybercycle.

MAIN OUTCOME MEASURES

Executive function (Color Trails Difference, Stroop C, Digits Backward); clinical status (mild cognitive impairment; MCI); exercise effort/fitness; and plasma BDNF.

RESULTS

Intent-to-treat analyses, controlling for age, education, and cluster randomization, revealed a significant group X time interaction for composite executive function (p=0.002). Cybercycling yielded a medium effect over traditional exercise (d=0.50). Cybercyclists had a 23% relative risk reduction in clinical progression to MCI. Exercise effort and fitness were comparable, suggesting another underlying mechanism. A significant group X time interaction for BDNF (p=0.05) indicated enhanced neuroplasticity among cybercyclists.

CONCLUSIONS

Cybercycling older adults achieved better cognitive function than traditional exercisers, for the same effort, suggesting that simultaneous cognitive and physical exercise has greater potential for preventing cognitive decline.

TRIAL REGISTRATION

This study is registered at Clinicaltrials.gov NCT01167400.

Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults

This study examined the effect of virtual social facilitation and competitiveness on exercise effort in exergaming older adults. Fourteen exergaming older adults participated. Competitiveness was assessed prior to the start of exercise. Participants were trained to ride a "cybercycle;" a virtual reality-enhanced stationary bike with interactive competition. After establishing a cybercycling baseline, competitive avatars were introduced. Pedaling effort (watts) was assessed. Repeated measures ANOVA revealed a significant group (high vs low competitiveness) × time (pre- to post-avatar) interaction (F[1,12] = 13.1, P = 0.003). Virtual social facilitation increased exercise effort among more competitive exercisers. Exercise programs that match competitiveness may maximize exercise effort.

Interactions between adipose, bone, and muscle tissue markers during acute negative energy balance in male rowers

AIM

The purpose of this investigation was to study the influence of prolonged low-intensity single scull rowing exercise on plasma adipocytokine and osteokine concentrations in trained male rowers. Nine single scull rowers (age: 20.1±1.6 yrs; height: 184.1±4.6 cm; body mass: 81.2±5.3 kg; %body fat: 11.1±3.9) participated in this study.

METHODS

Venous blood samples were obtained before and after a ~2 h constant load on-water sculling training session (distance: 20.6±1.5 km; HR: 133±4 bpm; intensity: 80.3±1.7% of the HR turn-point).

RESULTS

The training session created an energy deficit of 1 200-1 500 kcal. Plasma adiponectin increased (+12.2%; P<0.05) while leptin decreased (-23.1%; P<0.05) at 30 min postexercise. Plasma osteocalcin (+23.7%; P<0.05) and type I carboxyterminal telopeptide (ICTP) (+28.6%; P<0.05) were increased on completion of the training session. Plasma IL-6 concentration was increased (P<0.05) about four-fold while insulin concentration was decreased (P<0.05) more than three-fold upon completion of exercise. There were no differences in TNF-α, glucose, testosterone and cortisol concentrations over time. Plasma adiponectin (r=0.59) and osteocalcin (r=0.57) concentrations measured immediately after the training session were related (P<0.05) to the distance covered.

CONCLUSION

Acute negative energy balance induced by a single endurance rowing training session elicited an inverse metabolic response in adiponectin and osteocalcin concentrations in male rowers. Our results suggest that peripheral markers of negative energy balance, such as adiponectin and osteocalcin, may serve as signals for metabolic reaction to the energy cost of acute exercise in athletes.

Relationship of blood pressure, behavioral mood state, and physical activity following caffeine ingestion in younger and older women

The purpose of this study was to examine the age-related differences in blood pressure, heart rate, and behavioral mood state after caffeine ingestion in younger and older women. Using a placebo-controlled, double-blind design, 10 younger (Y; 18-22 years) and 10 older (O; 50-67 years) healthy women who were moderate consumers of caffeine (self-reported mean intake: Y, 139 +/- 152 mg.day-1; O, 204 +/- 101 mg.day-1) were investigated. All volunteers were characterized for fasting plasma glucose, insulin, free-fatty acids and caffeine levels, body composition, cardiovascular fitness, physical activity, and energy intake. Before and after placebo and caffeine ingestion (5 mg.kg-1 fat-free mass; approximately 208-270 mg) test days, the following variables were measured in all subjects: plasma caffeine levels, heart rate, blood pressure, and behavioral mood state. Results showed that, following caffeine ingestion: (i) both systolic and diastolic blood pressure (SBP and DBP, respectively) increased significantly (p < 0.05) in the older women (SBP, 128.4 +/- 14.2 vs. 132.1 +/- 13.0 mm Hg (3%); DBP, 80.2 +/- 6.9 vs. 83.4 +/- 7.5 mm Hg (4%), whereas only DBP increased in the younger women (67.1 +/- 4.7 vs. 69.9 +/- 5.4 mm Hg (4.2%); p < 0.05); (ii) heart rate decreased significantly (Y, 59.2 +/- 8.7 to 53.9 +/- 10.6 beats.min-1 (p < 0.05); O, 61.9 +/- 9.2 to 59.2 +/- 8.4 beats.min-1 (p < 0.05)) in both groups; and (iii) self-reported feelings of tension and vigor increased and feelings of fatigue decreased (p < 0.05) in younger women, whereas depression decreased (p < or = 0.05) in older women. Self-reported level of physical activity was inversely related to change in DBP following caffeine ingestion in younger women. In conclusion, blood pressure response is augmented and subjective feelings of behavioral mood state are attenuated to a greater degree in older than in younger women following acute caffeine ingestion. Less physically active younger women are more vulnerable to the pressor response to caffeine than more active younger women. It should be noted that these findings are limited to moderate consumers of caffeine who abstained for 48 h prior to testing, and who ingested caffeine in pill form (approximately 240 mg).

Plasma adiponectin and insulin sensitivity in overweight and normal-weight middle-aged premenopausal women

Adiponectin has been reported to regulate systemic insulin sensitivity as a part of a broader control mechanism in energy balance. However, it is not clear whether adiponectin exerts its positive effects on insulin sensitivity equally in a wide range of obesity. We investigated the association of plasma adiponectin concentration with insulin resistance (IR) in a cross-sectional sample of 98 middle-aged premenopausal women with a wide range of obesity. In addition, we studied the relationship between adiponectin, body composition, and blood biochemical and cardiorespiratory fitness variables. Body composition and fat distribution were measured via dual-energy x-ray absorptiometry in normal-weight (NW) (n = 41, body mass index [BMI] < 25 kg/m(2)) and overweight (OW) (n = 57, BMI > or = 25 kg/m(2)) women. Fasting blood samples were obtained; adiponectin, leptin, insulin, glucose, and insulin-like growth factor-I were measured; and IR index was calculated. The IR index from fasting plasma insulin and plasma glucose levels was estimated using the homeostasis model assessment (HOMA), as follows: fasting plasma insulin (in microliter units per milliliter) x fasting plasma glucose (in millimoles per liter)/22.5. Adiponectin was significantly higher (P = .0001) in NW (14.7 +/- 4.7 microg/mL) compared with OW (9.9 +/- 3.1 microg/mL) women. Significant differences (P < .003) in body mass, BMI, percentage of fat mass, fat mass, trunk fat, trunk fat-leg fat ratio, leptin, insulin, and HOMA were also observed between NW and OW groups. Leptin was independently related to plasma adiponectin (beta = -.259, P = .001) in the overall study group. Plasma adiponectin was only related to trunk fat-leg fat ratio (beta = -.242, P = .002) among NW subjects, whereas plasma adiponectin was related to fat-free mass (beta = .182, P = .0001) and HOMA (beta = -.576, P = .002) among OW women. The inverse relationship between adiponectin and leptin concentrations suggests that leptin may be involved in the regulation of adiponectin in middle-aged premenopausal women. Our data also demonstrate that adiponectin may play an important role in sustaining insulin sensitivity only in OW middle-aged premenopausal women.

An acute bout of endurance exercise but not sprint interval exercise enhances insulin sensitivity

An acute bout of endurance exercise (EE) enhances insulin sensitivity, but the effects of sprint interval exercise (SIE) have not yet been described. We sought to compare insulin sensitivity at baseline and after an acute bout of EE and SIE in healthy men (n = 8) and women (n = 5) (age, 20.7 +/- 0.3 years; peak oxygen consumption (VO2 peak), 42.6 +/- 1.7 mL.kg(-1).min(-1); <1.5 days.week(-1) structured exercise; body fat, 21.1 +/- 1.9%). Subjects underwent 3 oral glucose tolerance tests (OGTT(s)) the day after each of the following 3 conditions: no exercise, baseline (OGTT(B)); SIE at approximately 125% VO(2 peak) (OGTT(SIE)); and EE at approximately 75% VO(2 peak )(OGTT(EE)). SIE and EE sessions were randomized for each subject. Subjects consumed identical meals the day preceding each OGTT. Two insulin sensitivity indices - composite whole-body insulin sensitivity index (ISI-COMP) and ISI-hepatic insulin sensitivity (HOMA) - were calculated, using previously validated formulas (ISI-COMP = 10 000/ radical(glucose(fasting)) x insulin(fasting) x glucose(mean OGTT) x insulin(mean OGTT)); ISI-HOMA = 22.5/(insulin(fasting) x glucose(fasting)), and the plasma concentrations of cytokines interleukin-6 and tumor necrosis factor-alpha were measured. There were no differences by sex for any condition (men vs. women, p > 0.05). Pearson's correlation coefficients between ISI-COMP and ISI-HOMA for each condition were highly correlated (p < 0.01), and followed similar patterns of response. ISI-COMP(EE) was 71.4% higher than ISI-COMP(B) (8.4 +/- 1.4 vs. 4.9 +/- 1.0; p < 0.01) and 40.0% higher than ISI-COMPSIE (8.4 +/- 1.4 vs. 6.0 +/- 1.5; p < 0.05), but there was no difference between ISI-COMP(B) and ISI-COMP(SIE) (p = 0.182). VO(2 peak) was highly correlated with both ISI-COMP and ISI-HOMA during baseline and SIE test conditions (p < 0.02). These findings demonstrate that an acute bout of EE, but not SIE, increases insulin sensitivity relative to a no-exercise control condition in healthy males and females. While these findings underscore the use of regular EE as an effective intervention strategy against insulin resistance, additional research examining repeated sessions of SIE on insulin sensitivity is warranted.

Moderate protein intake improves total and regional body composition and insulin sensitivity in overweight adults

A high protein intake (approximately 40% of energy intake) combined with aerobic and resistance exercise training is more closely associated with improved body composition and cardiovascular risk profile than a traditional protein intake (approximately 15% of intake) combined with moderate-intensity aerobic exercise. However, there is concern that such high-protein diets may adversely affect health. We therefore tested the hypothesis that moderate protein intake (approximately 25% of energy intake) would elicit similar benefits on body composition and metabolic profile as high protein intake. Twenty-four overweight/obese men and women (body mass index [BMI] = 32.2 +/- 3.4, percentage of body fat [%BF] = 37.3 +/- 8.0) were matched for BMI and %BF and randomly assigned to one of 3 groups for a 3-month nutrition/exercise training intervention: (1) high-protein diet (approximately 40% of energy intake) and combined high-intensity resistance and cardiovascular training (HPEx, n = 8, 5 female and 3 male), (2) moderate-protein diet (approximately 25% of energy intake) and combined high-intensity resistance and cardiovascular training (MPEx, n = 8, 5 female and 3 male), or (3) high-protein diet only (HPNx, n = 8, 5 female and 3 male). Total and regional body composition (dual-energy x-ray absorptiometry), insulin sensitivity (insulin sensitivity index to the oral glucose tolerance test), insulin-like growth factor-1 (IGF-1), IGF binding protein-1 (IGFBP-1), IGF binding protein-3 (IGFBP-3), and blood lipids were measured at baseline and after the intervention. All groups experienced significant (P < .05) and similar losses of body weight, BMI, and total and abdominal %BF, and similar improvements in insulin sensitivity (HPEx, 6.3 +/- 1.2 vs 9.5 +/- 0.98; MPEx, 6.2 +/- 1.4 vs 8.4 +/- 1.6; HPNx, 3.7 +/- 1.1 vs 7.0 +/- 1.1; insulin sensitivity index to the oral glucose tolerance test; P < .05) and leptin levels. Furthermore, the HPEx group demonstrated decreases in total cholesterol (TC) and triglycerides, and increases in IGF-1 and IGFBP-1. The MPEx group experienced decreases in TC, whereas the HPNx group had increases in high-density lipoprotein cholesterol, TC to high-density lipoprotein, IGF-1, and IGFBP-1. In conclusion, moderate protein intake elicits similar benefits in body composition and insulin sensitivity as a high-protein diet. These findings may have practical implications for individuals interested in diets containing elevated dietary protein.