CHO Intake Research Articles

Carbohydrate supplementation during a simulated 10-km open water swimming race: effects on physiological, perceptual parameters and performance.

ABSTRACT The aim of the present study was to test the effect of carbohydrate ingestion, simulating a 10-km open water race competition on energy cost (Csw), perceived exertion (RPE), heart rate (HR), stroke rate (SR) and performance. We hypothesized that carbohydrate ingestion would reduce Csw and RPE in elite open water swimmers (OW-swimmers) and improve performance. Eight elite OW-swimmers swam for 3 × 30 min with 20-s of interval necessary to collect data in the swimming flume at a pre-set pace corresponding to their 10-km race pace, followed by a time to exhaustion test (TTE) at 100% of the peak oxygen uptake (V̇O2peak). During the set, OW-swimmers ingested 45-g of carbohydrates (CHO) in 550-mL of water (8% solution) during each of the two intervals or a placebo solution (PLA). HR, RPE, V̇O2 and SR were measured. Shapiro–Wilk test was used to verify the normal distribution of data. Two-way repeated measures ANOVA and t-test was performed (p < 0.05). A significant difference emerged in TTE between the trials (169.00 ± 91.06 s in CHO; 102.31 ± 57.47 s in PLA). HR, RPE and SR increased during the TTE but did not differ between trials. Csw did not show a significant main effect between the two conditions and in time course in both conditions. CHO ingestion significantly increased TTE at 100% of V̇O2peak after 90-min of swimming at 10-km race pace. These findings indicate that CHO intake during a 10-km open water swimming competition should have a beneficial impact on performance in the final part of the race.

Effects of two different doses of carbohydrate ingestion on taekwondo-related performance during a simulated tournament

BackgroundCarbohydrate (CHO) ingestion enhances exercise performance; however, the efficacy of CHO intake on repeated bouts of exercise simulating a taekwondo tournament is unknown. Therefore, the purpose was to compare the effects of two different doses of CHO on a sports-specific kicking test during a simulated taekwondo tournament compared to placebo (PLA).MethodsIn a double-blind, randomized-placebo controlled, cross-over trial, eleven junior male professional taekwondo athletes (age: 16 ± 0.8 years, body mass: 55.3 ± 7.3 kg) ingested one of three solutions: (i) high dose (C45): 45 g of CHO (60 g∙h− 1), (ii) low dose (C22.5): 22.5 g of CHO (30 g∙h− 1; both solutions containing 2:1 glucose:fructose), or a PLA immediately following each kicking test. The kicking test was repeated 5 times, separated by 45 mins of rest, simulating a typical taekwondo competition day. Ratings of perceived exertion (RPE) and gastrointestinal discomfort (GI) scores were collected immediately after, and blood glucose before each test.ResultsThe results revealed that C45 and C22.5 did not improve total, successful, or percentage of successful kicks compared to PLA (p > 0.05). Blood glucose was significantly higher following both CHO conditions compared with PLA across all five tests (p < 0.05). There were no differences between treatments or across tests for RPE (p > 0.05).ConclusionCHO intake, independent of the dose, did not alter taekwondo kick performance during a simulated taekwondo tournament.

Effects of Reduced Carbohydrate Intake after Sprint Exercise on Breath Acetone Level.

Assessment of breath acetone level may be an alternative procedure to evaluate change in fat metabolism. The purpose of the present study was to investigate the effect of insufficient carbohydrate (CHO) intake after sprint exercise on breath acetone level during post-exercise. Nine subjects conducted two trials, consisting of either reduced CHO trial (LOW trial) or normal CHO trial (NOR trial). In each trial, subjects visited to laboratory at 7:30 following an overnight fast to assess baseline breath acetone level. They commenced repeated sprint exercise from 17:00. After exercise, isoenergetic meals with different doses of CHO (LOW trial; 18% for CHO, 27% for protein, 55% for fat, NOR trial; 58% for CHO, 14% for protein, 28% for fat) were served. Breath acetone level was also monitored immediately before and after exercise, 1 h, 3 h, 4 h, and 15 h (on the following morning) after completing exercise. A significant higher breath acetone level was observed in LOW trial than in NOR trial 4 h after completion of exercise (NOR trial; 0.66 ppm, LOW trial; 0.9 ppm). However, breath acetone level did not differ on the following morning between two trials. Therefore, CHO intake following an exhaustive exercise affects breath acetone level during early phase of post-exercise.

Comparison of two carbohydrate intake strategies to improve glucose control during exercise in adolescents and adults with type 1 diabetes

Background and aimsDuring aerobic physical activity (PA), hypoglycemia is common in people with type 1 diabetes (T1D). Few studies have compared the effectiveness of different carbohydrate (CHO) intake strategies to prevent PA-induced hypoglycemia. Our objective was to compare the efficacy of two CHO intake strategies, same total amount but different CHO intake timing, to maintain glucose levels in the target range (4.0–10.0 mmol/L) during PA in people with T1D. Methods and resultsAn open-label, randomized, crossover study in 33 participants (21 adults; 12 adolescents). Participants practiced 60 min PA sessions (ergocyle) at 60% VO2peak 3.5 h after lunch comparing an intake of 0.5 g of CHO per kg of body weight applied in a pre-PA single CHO intake (SCI) or in a distributed CHO intake (DCI) before and during PA. The percentage of time spent in glucose level target range during PA was not different between the two strategies (SCI: 75 ± 35%; DCI: 87 ± 26%; P = 0.12). Hypoglycemia (<4.0 mmol/L) occurred in 4 participants (12%) with SCI compared to 6 participants (18%) with DCI (P = 0.42). The SCI strategy led to a higher increase (P = 0.01) and variability of glucose levels (P = 0.04) compared with DCI. ConclusionsIn people living with T1D, for a 60 min moderate aerobic PA in the post-absorptive condition, a 0.5 g/kg CHO intake helped most participants maintain acceptable glycemic control with both strategies. No clinically significant difference was observed between the SCI and DCI strategies.ClinicalTrials.gov Identifier: NCT03214107 (July 11, 2017).

The metabolic and performance effects of carbohydrate timing in resistance trained males undergoing a carbohydrate restricted diet.

The purpose of this investigation was to examine the importance of carbohydrate (CHO) timing while consuming a carbohydrate restricted diet (CRD) and completing a high-intensity exercise program. Eighteen males completed 6 weeks of training with the first 2 weeks serving as familiarization. During the final 4 weeks, subjects were randomized into 2 groups and completed 3 days of resistance training and 2 days of high-intensity interval training, while consuming a CRD (∼25%, ∼25%, and ∼50%, CHO, protein, and fat, respectively). The supplemented group (n= 9) ingested 30g of CHO during exercise and 40g of CHO immediately after each training session. The non-supplemented group (n= 9) consumed a non-caloric placebo during exercise. Pre- and post-testing measures included back squat and bench press 1-repetition maximums (1-RM), peak oxygen consumption (V̇O2peak), anaerobic power, body composition, fasted glucose, insulin, and total testosterone. Both groups significantly improved back squat and bench press 1-RM, V̇O2peak, and power output (p< 0.05), but there were no differences in blood markers or body composition. Our data suggests that CHO timing does not negatively impact training adaptations during a high-intensity exercise regimen when dietary CHO intake is restricted, but that favorable adaptations can be made while consuming a CRD. Novelty: Carbohydrate restricted dieting has no negative impact on resistance training adaptations. Short-term high-intensity interval training is effective in increasing peak oxygen consumption.

Dietary carbohydrate intake in patients with type 2 diabetes mellitus and diabetes control: a cross-sectional study.

BackgroundFood intake has important implications for patients with type 2 diabetes.ObjectiveSimilarly, in other crop species, this observational study aimed to assess dietary carbohydrate (CHO) and non-starch polysaccharide (NSP) intake and examine their association with glycemic control among Saudi patients with type 2 diabetes mellitus (T2DM).DesignWe investigated dietary intake in 404 patients (207 males and 197 females) with T2DM between November 2018 and March 2019. Dietary intake was assessed by face-to-face interviews using a validated dietary questionnaire.ResultsThe results revealed that dietary CHO intake (67% of energy) exceeded the recommended daily intake, and white rice (Basmati rice) was the major contributor to CHO intake. However, the dietary NSP intake was lower than recommended, and it was negatively associated with HbA1c levels.ConclusionThis cross-sectional study showed that dietary CHO intake was high among Saudi patients with type 2 diabetes, and that their daily intake of NSPs was correlated with a lower level of HbA1c. Dietary advice should be given for patients with diabetes to reduce their intake of starchy food such as rice.

Ketone bodies as an energy source: regular-grade, premium, or super-fuel to power the mitochondrial engine?

Ketone bodies as an energy source: regular-grade, premium, or super-fuel to power the mitochondrial engine?

Dietary intake and menstrual cycle changes in international level young athletes

Few studies have examined the influence of nutritional status and mental stress on menstrual cycle characteristics. The purpose of this study was to describe the impact of low energy availability (EA) and mental health problems on the menstrual cycles of elite female rowing competitors during a survey period. We enrolled sixteen subjects (16-18 years old) who were elite female rowing competitors preparing for an international competition. This study provides the first long-term assessment of dietary intake, body mass/composition, state of anxiety, and menstrual cycle in international level female athletes. Dietary energy intake increased significantly during the investigation period (P<0.001). CHO intake increased significantly during the investigation period (P<0.005). EA significantly increased during the investigation period (P<0.01). The percentage of athletes with menstrual dysfunction was 20.0% in April 2018 (2 of 10), but none of the athletes reported menstrual dysfunction in October 2019. The mental status measured by state anxiety index (STAI) did not change significantly during this survey period (P>0.05). There was no athlete who has menstrual disfunction after sufficient CHO intake during this survey period. These findings of this study suggest that adequate EA levels and sufficient CHO intake might lead to improved menstrual function. In addition, the impact of psychological factors on menstrual dysfunction at normal levels may be less than the effects of nutritional status.

Carbohydrate and fat intake associated with risk of metabolic diseases through epigenetics of CPT1A

Epigenome-wide association studies identified the cg00574958 DNA methylation site at the carnitine palmitoyltransferase-1A (CPT1A) gene to be associated with reduced risk of metabolic diseases (hypertriglyceridemia, obesity, type 2 diabetes, hypertension, metabolic syndrome), but the mechanism underlying these associations is unknown. We aimed to elucidate whether carbohydrate and fat intakes modulate cg00574958 methylation and the risk of metabolic diseases. We examined associations between carbohydrate (CHO) and fat (FAT) intake, as percentages of total diet energy, and the CHO/FAT ratio with CPT1A-cg00574958, and the risk of metabolic diseases in 3 populations (Genetics of Lipid Lowering Drugs and Diet Network, n=978; Framingham Heart Study, n=2331; and REgistre GIroní del COR study, n=645) while adjusting for confounding factors. To understand possible causal effects of dietary intake on the risk of metabolic diseases, we performed meta-analysis, CPT1A transcription analysis, and mediation analysis with CHO and FAT intakes as exposures and cg00574958 methylation as the mediator. We confirmed strong associations of cg00574958 methylation with metabolic phenotypes (BMI, triglyceride, glucose) and diseases in all 3 populations. Our results showed that CHO intake and CHO/FAT ratio were positively associated with cg00574958 methylation, whereas FAT intake was negatively correlated with cg00574958 methylation. Meta-analysis further confirmed this strong correlation, with β=58.4±7.27, P=8.98 x 10-16 for CHO intake; β = -36.4±5.95, P=9.96 x 10-10 for FAT intake; and β=3.30±0.49, P=1.48 x 10-11 for the CHO/FAT ratio. Furthermore, CPT1A mRNA expression was negatively associated with CHO intake, and positively associated with FAT intake, and metabolic phenotypes. Mediation analysis supports the hypothesis that CHO intake induces CPT1A methylation, hence reducing the risk of metabolic diseases, whereas FAT intake inhibits CPT1A methylation, thereby increasing the risk of metabolic diseases. Our results suggest that the proportion of total energy supplied by CHO and FAT can have a causal effect on the risk of metabolic diseases via the epigenetic status of CPT1A.Study registration at https://www.clinicaltrials.gov/: the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN)-NCT01023750; and the Framingham Heart Study (FHS)-NCT00005121.

Carbohydrate Consumption and Periodization Strategies Applied to Elite Soccer Players.

During a soccer season, athletes tend to play intense and light matches such as decisive and qualifying games. The amount of muscle glycogen stores is a determining factor of performance during exercise, and manipulation of carbohydrate intake during the soccer season to enhance muscle glycogen stores can improve the performance of elite soccer players. The purpose of this review is to provide a holistic view of the periodization of carbohydrates and their effects on sports performance, based on what the literature recommends for the periodization of carbohydrates for endurance athletes, and of muscle glycogen recovery and compensation among professional soccer players. The ingestion of large amounts of carbohydrates (CHO;10g/kg of body weight (BW)/day) is important 36h before a match for the elite soccer player to ensure muscle glycogen supercompensation. In addition, elite soccer players should intake 1 to 1.5g/kg BW/h within the first 4h after a soccer game to maximize glycogen resynthesis. However, the season is comprised of away and home games that require different intensities; thus, soccer players need to periodize CHO intake based on evidence-based recommendations such as "train low," "train low, compete high," and/or "sleep low." The goal is to induce training adaptations by alternating with high or low CHO availability based on seasons, matches, and training intensities. The strategy can result in improved performance during games. Periodizing the consumption of carbohydrates, based on the intensity of training and matches, should include more carbohydrates when the matches require higher intensity and fewer carbohydrates when they require lower intensity; this is a strategy that will improve the performance of elite soccer athletes.

Lower Daily Carbohydrate Intake Is Associated With Improved Glycemic Control in Adults With Type 1 Diabetes Using a Hybrid Closed-Loop System.

To assess the association between daily carbohydrate (CHO) intake and glycemic control in adult hybrid closed-loop (HCL) users with type 1 diabetes (T1D). Mean individual daily CHO intake (MIDC) and relative deviation from MIDC (≤80% low, 81-120% medium, >120% high CHO consumption) were compared with parameters of glycemic control assessed by continuous glucose monitoring. Records from 36 patients (26 male, 10 female; age 36.9 ± 13.5 years; HbA1c 7.1 ± 0.9% [54 ± 10 mmol/mol]) provided 810 days of data (22.5 ± 6.7 days per patient). Time in range (70-180 mg/dL) for low, medium, and high CHO consumption was 77.4 ± 15.4%, 75.2 ± 16.7%, and 70.4 ± 17.8%, respectively (P < 0.001). Time above range (>180 mg/dL) was 20.1 ± 14.7%, 22.0 ± 16.9%, and 27.2 ± 18.4%, respectively (P < 0.001). There was no between-group difference for time in hypoglycemia (<70 mg/dL; P = 0.50). Daily CHO intake was inversely associated with glycemic control in adults with T1D using an HCL system. Lower CHO intake may be a strategy to optimize glucose control in HCL users.

Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability.

Key points Brief (5–6 days) adaptation to a low carbohydrate high fat diet in elite athletes increased exercise fat oxidation to rates previously observed with medium (3–4 weeks) or chronic (>12 months) adherence to this diet, with metabolic changes being washed out in a similar time frame.Increased fat utilisation during exercise was associated with a 5–8% increase in oxygen cost at speeds related to Olympic Programme races.Acute restoration of endogenous carbohydrate (CHO) availability (24 h high CHO diet, pre‐race CHO) only partially restored substrate utilisation during a race warm‐up. Fat oxidation continued to be elevated above baseline values although it was lower than achieved by 5–6 days’ keto adaptation; CHO oxidation only reached 61% and 78% of values previously seen at exercise intensities related to race events.Acute restoration of CHO availability failed to overturn the impairment of high‐intensity endurance performance previously associated with low carbohydrate high fat adaptation, potentially due to the blunted capacity for CHO oxidation. We investigated substrate utilisation during exercise after brief (5–6 days) adaptation to a ketogenic low‐carbohydrate (CHO), high‐fat (LCHF) diet and similar washout period. Thirteen world‐class male race walkers completed economy testing, 25 km training and a 10,000 m race (Baseline), with high CHO availability (HCHO), repeating this (Adaptation) after 5–6 days’ LCHF (n = 7; CHO: <50 g day−1, protein: 2.2 g kg−1 day−1; 80% fat) or HCHO (n = 6; CHO: 9.7 g kg−1 day−1; protein: 2.2 g kg−1 day−1) diet. An Adaptation race was undertaken after 24 h HCHO and pre‐race CHO (2 g kg−1) diet, identical to the Baseline race. Substantial (>200%) increases in exercise fat oxidation occurred in the LCHF Adaptation economy and 25 km tests, reaching mean rates of ∼1.43 g min−1. However, relative V˙O2 (ml min−1 kg−1) was higher (P < 0.0001), by ∼8% and 5% at speeds related to 50 km and 20 km events. During Adaptation race warm‐up in the LCHF group, rates of fat and CHO oxidation at these speeds were decreased and increased, respectively (P < 0.001), compared with the previous day, but were not restored to Baseline values. Performance changes differed between groups (P = 0.009), with all HCHO athletes improving in the Adaptation race (5.7 (5.6)%), while 6/7 LCHF athletes were slower (2.2 (3.4)%). Substrate utilisation returned to Baseline values after 5–6 days of HCHO diet. In summary, robust changes in exercise substrate use occurred in 5–6 days of extreme changes in CHO intake. However, adaptation to a LCHF diet plus acute restoration of endogenous CHO availability failed to restore high‐intensity endurance performance, with CHO oxidation rates remaining blunted.

Ingestion of Carbohydrate Prior to and during Maximal, Sprint Interval Cycling Has No Ergogenic Effect: A Randomized, Double-Blind, Placebo Controlled, Crossover Study.

Carbohydrate (CHO) ingestion may improve intermittent sprint performance in repeated sprint efforts ≤15 s. Yet, evidence for its efficacy on sprint interval durations ~30 s is lacking. The purpose of this study was to investigate the effects of CHO ingestion on maximal sprint interval exercise. Fifteen (n = 15) recreational athletes (13/2 males/females, age 22 ± 2 years; height 176 ± 11 cm; mass 76.8 ± 11.3 kg) volunteered for this randomised, double-blind, placebo-controlled, crossover design. Participants completed two experimental trials (performed 10-days apart) involving the ingestion of an 8% CHO solution or a flavour and appearance-matched placebo (PLA) solution (5 mL/kg/bw), immediately before exercise, and preceding the second interval of four × 30 s bouts of repeated maximal sprint efforts (separated by 3.5 min of passive recovery). Peak and mean power (W) output progressively decreased during the repeated sprints (main effect of time, p < 0.0001), but there were no differences between CHO and PLA during any of the sprints (p > 0.05 for condition main effect and condition × time interaction). Physiological responses (blood lactate, heart rate, oxygen consumption, respiratory exchange ratio and RPE) were also unaltered by CHO ingestion. In conclusion, CHO ingestion does not enhance performance or modulate physiological responses during intermittent maximal, sprint cycling.

Effects of 120 vs. 60 and 90 g/h Carbohydrate Intake during a Trail Marathon on Neuromuscular Function and High Intensity Run Capacity Recovery.

Background: Current carbohydrate (CHO) intake recommendations for ultra-trail activities lasting more than 2.5 h is 90 g/h. However, the benefits of ingesting 120 g/h during a mountain marathon in terms of post-exercise muscle damage have been recently demonstrated. Therefore, the aim of this study was to analyze and compare the effects of 120 g/h CHO intake with the recommendations (90 g/h) and the usual intake for ultra-endurance athletes (60 g/h) during a mountain marathon on internal exercise load, and post-exercise neuromuscular function and recovery of high intensity run capacity. Methods: Twenty-six elite trail-runners were randomly distributed into three groups: LOW (60 g/h), MED (90 g/h) and HIGH (120 g/h), according to CHO intake during a 4000-m cumulative slope mountain marathon. Runners were measured using the Abalakov Jump test, a maximum a half-squat test and an aerobic power-capacity test at baseline (T1) and 24 h after completing the race (T2). Results: Changes in Abalakov jump time (ABKJT), Abalakov jump height (ABKH), half-squat test 1 repetition maximum (HST1RM) between T1 and T2 showed significant differences by Wilcoxon signed rank test only in LOW and MED (p < 0.05), but not in the HIGH group (p > 0.05). Internal load was significantly lower in the HIGH group (p = 0.017) regarding LOW and MED by Mann Whitney u test. A significantly lower change during the study in ABKJT (p = 0.038), ABKH (p = 0.038) HST1RM (p = 0.041) and in terms of fatigue (p = 0.018) and lactate (p = 0.012) within the aerobic power-capacity test was presented in HIGH relative to LOW and MED. Conclusions: 120 g/h CHO intake during a mountain marathon might limit neuromuscular fatigue and improve recovery of high intensity run capacity 24 h after a physiologically challenging event when compared to 90 g/h and 60 g/h.

Examination Of Low Energy Availability (LEA) And Macronutrient Intake Among Beach Volleyball Players

Low energy availability (LEA) may be prevalent in female collegiate beach volleyball players, which can be a catalyst for negative health consequences. Athletes can present in a state of LEA as a result of inadequate intake of the recommended macronutrients; those being proteins (PRO), carbohydrates (CHO), and fats. PURPOSE: Examine the prevalence of LEA and macronutrient intakes (PRO, CHO, and fats) among NCAA Division I female collegiate beach volleyball players. METHODS: Data from a larger cross-sectional study was used to examine recreational athletes (n=18; age: 19.8±1.4 years; height: 174.4±5.5 cm; weight: 63.2±5.1 kg). Athletes were moderately trained (exercised a minimum of 3-4 days/week). Data collection consisted of anthropometric data, surveys (e.g., demographics, age, gender, etc.), resting metabolic rate (RMR), a 7-day online dietary log to measure energy intake (EI), and exercise logs to measure exercise energy expenditure (EEE). Basic descriptive statistics, Chi-squares, and cross-tabulations were used to examine the proportion of participants classified as “at risk” for LEA (<30 kcal/kg/FFM) and the proportion that met the macronutrient recommendations. RESULTS: Overall, beach volleyball players demonstrated the following, with 94.4% (n=17) being identified as at risk for LEA: Average energy availability (EA): 12.4±9.6 kcal/kg FFM and average EEE: 1108.7±157.6 kcals. RMR recommendations for average minimal caloric intake for the sample was 1477.7±272.3 kcals; however, 55.6% (n=10) did not meet the recommendations. Recommended CHO and PRO macronutrient intake were not met by 100% and 61.1% of the sample, respectively. Overconsumption of fat compared to the recommendation was found in 33.3%. CONCLUSIONS: Beach volleyball athletes in this sample were severely and alarmingly at risk for LEA. Most of the athletes demonstrated low CHO and PRO intake while overconsuming fat compared to the recommendations. These athletes would benefit from nutrition education focused on properly fueling and macronutrient intake, which are both essential for elite performance in the athletic arena.

Comparable Exogenous Carbohydrate Oxidation With Lactose Or Sucrose Feeding During Endurance Exercise

PURPOSE: Endogenous carbohydrate (CHO) availability can limit endurance exercise performance. CHO ingested during exercise such as glucose, glucose polymers and sucrose are readily oxidized and can improve endurance performance. The extent to which lactose can be utilized as a fuel source during exercise is unknown. The purpose is to elucidate the metabolic response to lactose ingestion during endurance exercise, compared to sucrose or water. METHODS: 11 participants (mean ± SD: 22 ± 4 years, 50.9 ± 4.7 ml.min-1.kg-1) cycled for 150 min at 50% of Wmax on 3 occasions. During exercise participants ingested, in a randomized order, water (WAT), lactose (LAC) or sucrose (SUC) containing beverages; a CHO dose of 0.8 g.min-1 (48 g.h-1) was used. Indirect calorimetry was used to calculate fat and total CHO oxidation and stable isotope tracer methodology (natural high 13C abundance CHO ingestion, 13C:12C ratio determination in expired breath by isotope-ratio mass spectrometry) was used to quantify exogenous CHO oxidation. Venous blood samples were taken throughout exercise and analyzed for glucose, lactate and non-esterified fatty acids (NEFA). RESULTS: Mean exogenous CHO oxidation rates in LAC (0.55 ± 0.19 g.min-1) and SUC (0.58 ± 0.10 g.min-1) were similar (P=0.68). Endogenous CHO oxidation contributed less to energy expenditure (EE) in LAC (39 ± 14 %) than in WAT (50 ± 11 %, P=0.01) and SUC (50 ± 8 %, P=0.04). Fat oxidation contributed most to EE in WAT (50 ± 11 %), which was significantly greater than in LAC (42 ± 8 %, P=0.04) and SUC (28 ± 6 %, P<0.01), with fat oxidation higher in LAC than SUC (P<0.01). Plasma glucose was significantly higher in LAC (5.2 ± 0.4 mmol.L-1) and SUC (5.3 ± 0.5 mmol.L-1) than WAT (4.6 ± 0.5 mmol.L-1, P≤0.01). Plasma lactate was significantly higher in SUC (1.7 ± 0.5 mmol.L-1) than WAT (1.5 ± 0.4 mmol.L-1, P<0.01). Plasma NEFA were significantly higher in WAT (1.1 ± 0.4 mmol.L-1) than SUC (0.5 ± 0.3 mmol.L-1, P<0.01), and tended to be higher in WAT than LAC (0.7 ± 0.4 mmol.L-1, P=0.08). CONCLUSIONS: Exogenous CHO oxidation during exercise was comparable from ingested lactose and sucrose. However, lactose ingestion promoted higher fat and lower endogenous CHO oxidation during exercise than sucrose. This suggests that lactose may be at least as efficacious as commonly used CHO sources for improving exercise performance.

An Investigation Of Dietary Patterns And Macronutrient Intakes Among Resistance-trained Men

PURPOSE: This study aimed to assess the adequacy of dietary patterns and macronutrient intakes in support of the adaptations to resistance training within a weekly microcycle of resistance-trained (RT) men using traditional dietary assessment methods. METHODS: Thirty-seven RT men (age (y) Mdn (IQR) 24.9 (20.7-29.7), body mass (kg) M (SD) 81.3 (11.8)) were recruited to participate in this study. Dietary data were collected by self-reported 7-day weighed intake record and analysed on both a daily and per eating occasion (EO) basis using nutrition software. Adequacy was assessed against recommendations for this population (ACSM, 2016; IOC, 2018). Data are reported as M (SD), Mdn (25-75 percentile) and p-value (p). RESULTS: Average daily energy intake for training day (TD) and rest day (RD) was 36 (7) and 34 (8) kcal·kg-1·d-1, respectively. Daily protein (PRO) intake (g·kg-1·d-1) was significantly greater than recommended minimum (1.6 g·kg-1·d-1) on TD [2.1 (0.5), P < .001) but was not different on RD [1.8 (0.6), P = .058]. Carbohydrate (CHO) intake (g·kg-1·d-1) was significantly lower than 5 g·kg-1·d-1 on both TD [3.5 (1.1), P < .001], and RD [3.3 (1.0), P < .001)]. Daily frequency of EO was significantly higher than the recommended 3-4 EO (P < .001) for TD [5 (5-6)] and RD [5 (4-5)]. When analysed per EO (g·kg-1·EO-1), average PRO intake was significantly greater per main meal (MM) on TD [0.5 (0.4-0.6), P < .001] and RD [0.5 (0.4-0.6), P < .001], but not significantly different per snack (SN) [0.2 (0.1-0.3)] for TD (P = .254) and RD (P = .111) vs recommended 0.25 g·kg1·EO-1. CHO intake (g·kg-1·EO-1) per MM was 0.9 (0.7-1.1) for TD and 1.0 (0.7-1.1) for RD. CHO (g·kg-1·EO-1) consumed per SN was 0.4 (0.3-0.5) for both TD and RD. Daily number of MM was 3 (3-3) for TD and RD, and of SN were 3 (2-4) for TD, 2 (1-3) for RD. CONCLUSION: RT men met dietary recommendations to optimise adaptation to resistance training. However, the traditional dietary assessment methods do not address the importance of quantity, quality (source), timing, distribution and frequency of nutrients relative to a specific training session, termed peri-training nutrition (PTN), to optimise training adaptation. Future work must work towards analysis methods in support of periodised, personalised nutrition, relative to a specific training stimulus. FHI Grant TC20130001.

Examination Of Energy Needs Across 2-week High-Intense Functional Exercise Program In Recreational Athletes

Increases in physical activity without proper nutritional knowledge may expose recreational athletes to compromised energy needs and macronutrient profiles. PURPOSE: To examine the energy needs across a 2-week high intense functional exercise program in female and male recreational athletes. METHODS: Thirty adults (age: 31.2 ± 8.1; females: 164.7 ± 7.1 cm, 69.9 ± 11.1 kg; body fat%: 29.2 ± 5.5%; males: n=12, 176.9 ± 6.2 cm, 89.5 ± 15.1 kg, body fat%: 22.3 ± 8.8%) participated in a larger cross-sectional study. Participants completed a demographic survey, a 7 day online dietary and exercise log across 2 weeks. Measurements included; height, weight, and DXA scan (body fat%) at the beginning of the study. Exercise energy expenditure (EEE) was calculated using Ainsworth/Heyward equations, energy availability (EA) was calculated by EA = ((EI - EEE)/FFM.kg-1) and energy balance (EB) was calculated by EB = (EI – TDEE = 0). Macronutrients (CHO, PRO, and fats) were assessed using ACSM recommendations (recs.). Low EA (LEA) was defined at >30 kcals/FFM.kg-1 and EB was defined as negative, balanced, or positive, and Macros were defined as low, within or above recs. RESULTS: Results yielded LEA (week 1: 73.3%, n = 22, week 2: 80% n=24) and negative EB (week 1: 94.4%, n=17; 75.0%, n=9) across the two weeks. No significant differences were found between gender or training weeks for energy needs and Macros. Over the 2 weeks, participants demonstrated similar energy needs including: EI (week 1: 1752.3 ± 599.8 kcals, week 2: 1831.2 ± 634.4 kcals), EEE (week 1: 310.7 ± 63.7 kcals, week 2:302.7 ± 62.1 kcals), EA: (week 1: 25 ± 10.1 kcals/FFM.kg-1, week 2: 25.1 ± 9.8 kcals/FFM.kg-1), TDEE (week 1: 2518.5 ± 266.1 kcals, week 2: 2543.1 ± 286.1 kcals), and EB (week 1: -766.2 ± 627.4 kcals, week 2: -712 ± 652.3 kcals). Macronutrients were also similar between weeks; with PRO intake within recommendations (week 1: 50%, n=15; week 2: 63%, n=17, n=6), CHO intake was extremely low (week 1: 96.7%, n=29; week 2: 93.3%, n=28,) and fats were within recs. (week 1: 62.1%, n=18; week 2: 46.7%, n=9). CONCLUSION: Participants demonstrated consistent EI and EEE habits over the 2 weeks, however, the recreational athletes under consumed CHO and presented at risk for LEA and negative EB. This leads to compromised fueling for the EEE utilized during training. Funded by Avadim Technology

Comparable Exogenous Carbohydrate Oxidation from Lactose or Sucrose during Exercise.

ABSTRACTPurposeIngesting readily oxidized carbohydrates (CHO) such as sucrose during exercise can improve endurance performance. Whether lactose can be utilized as a fuel source during exercise is unknown. The purpose of this study was to investigate the metabolic response to lactose ingestion during exercise, compared with sucrose or water.MethodsEleven participants (age, 22 ± 4 yr; V̇O2peak, 50.9 ± 4.7 mL·min−1·kg−1) cycled at 50% Wmax for 150 min on five occasions. Participants ingested CHO beverages (lactose or sucrose; 48 g·h−1, 0.8 g·min−1) or water throughout exercise. Total substrate and exogenous CHO oxidation was estimated using indirect calorimetry and stable isotope techniques (naturally high 13C-abundance CHO ingestion). Naturally low 13C-abundance CHO trials were conducted to correct background shifts in breath 13CO2 production. Venous blood samples were taken to determine plasma glucose, lactate, and nonesterified fatty acid concentrations.ResultsMean exogenous CHO oxidation rates were comparable with lactose (0.56 ± 0.19 g·min−1) and sucrose (0.61 ± 0.10 g·min−1; P = 0.49) ingestion. Endogenous CHO oxidation contributed less to energy expenditure in lactose (38% ± 14%) versus water (50% ± 11%, P = 0.01) and sucrose (50% ± 7%, P ≤ 0.05). Fat oxidation was higher in lactose (42% ± 8%) than in sucrose (28% ± 6%; P ≤ 0.01); CHO conditions were lower than water (50% ± 11%; P ≤ 0.05). Plasma glucose was higher in lactose and sucrose than in water (P ≤ 0.01); plasma lactate was higher in sucrose than in water (P ≤ 0.01); plasma nonesterified fatty acids were higher in water than in sucrose (P ≤ 0.01).ConclusionsLactose and sucrose exhibited similar exogenous CHO oxidation rates during exercise at moderate ingestion rates. Compared with sucrose ingestion, lactose resulted in higher fat and lower endogenous CHO oxidation.

682-P: Carbohydrate Needs for Prolonged Fasted Exercise with and without Basal Rate Reductions in CSII

The amount of oral carbohydrate (CHO) needed to prevent hypoglycemia during prolonged fasted exercise in CSII is unclear. We assessed CHO intake needs during 3 different basal rate strategies during prolonged fasted exercise in active patients with T1D. Individuals with T1D on CSII (n=15) completed three 120-min treadmill exercise (∼45% of VO2peak) visits in a randomized crossover design. Strategies included: A) no basal rate reduction (BRR) and a dextrose intake of 0.3 g/kg/hr when BG was &amp;lt;10mmol/L (CHO only); B) a 50% BRR set 90 min pre-exercise, with dextrose as needed to treat hypoglycemia (50% BRR); and C) a 50% BRR set at exercise start plus dextrose intake of 0.3 g/kg/hr when BG was &amp;lt;10 mmol/L (Combo). Glycemia was higher in C compared to A or B by 105 min of exercise (P &amp;lt; 0.05). The drop in blood glucose during exercise was greater in A (-2.7 ± 3.4 mmol/L) than in B (-1.9 ± 2.5 mmol/L) or C (0.3 ± 2.6 mmol/L). Total CHO intake was 38.0 ± 18.8 g, 0.8 ± 3.1 g, and 29.5 ± 16.2 g, for A, B and C, respectively. Compared to A, B had lower RER (0.83 ± 0.04 vs. 0.79 ± 0.04), higher ketones (0.1 ± 0.1 vs. 0.4 ± 0.3 mmol/L), greater net loss of calories (709.2 ± 217.4 vs. 859.7 ± 239.6 kcal) and greater fat oxidation rate (0.39 ± 0.1 vs. 0.51 ± 0.2 g/min) (all P &amp;lt; 0.05). A BRR, set 90 min prior to exercise is associated with good glycemic control and an increased rate of lipid oxidation compared to CHO feeding alone or combined BRR and CHO feeding approach at exercise onset. Disclosure S.M. McGaugh: None. R. Pooni: None. D. Zaharieva: Speaker’s Bureau; Self; Ascensia Diabetes Care, Insulet Corporation, Medtronic. N.C. D’Souza: None. T. Vienneau: Employee; Self; Insulet Corporation. Stock/Shareholder; Self; Insulet Corporation. T.T. Ly: Employee; Self; Insulet Corporation. M. Riddell: Advisory Panel; Self; Zucara Therapeutics Inc. Consultant; Self; Lilly Diabetes. Research Support; Self; Dexcom, Inc., Insulet Corporation. Speaker’s Bureau; Self; Medtronic, Novo Nordisk A/S. Funding Insulet Corporation