Protein and amino acids for athletes

The main determinants of an athlete's protein needs are their training regime and habitual nutrient intake. Most athletes ingest sufficient protein in their habitual diet. Additional protein will confer only a minimal, albeit arguably important, additional advantage. Given sufficient energy intake, lean body mass can be maintained within a wide range of protein intakes. Since there is limited evidence for harmful effects of a high protein intake and there is a metabolic rationale for the efficacy of an increase in protein, if muscle hypertrophy is the goal, a higher protein intake within the context of an athlete's overall dietary requirements may be beneficial. However, there are few convincing outcome data to indicate that the ingestion of a high amount of protein (2-3 g x kg(-1) BW x day(-1), where BW = body weight) is necessary. Current literature suggests that it may be too simplistic to rely on recommendations of a particular amount of protein per day. Acute studies suggest that for any given amount of protein, the metabolic response is dependent on other factors, including the timing of ingestion in relation to exercise and/or other nutrients, the composition of ingested amino acids and the type of protein.     

Considerations for protein intake in managing weight loss in athletes

Abstract

A large body of evidence now shows that higher protein intakes (2–3 times the protein Recommended Dietary Allowance (RDA) of 0.8 g/kg/d) during periods of energy restriction can enhance fat-free mass (FFM) preservation, particularly when combined with exercise. The mechanisms underpinning the FFM-sparing effect of higher protein diets remain to be fully elucidated but may relate to the maintenance of the anabolic sensitivity of skeletal muscle to protein ingestion. From a practical point of view, athletes aiming to reduce fat mass and preserve FFM should be advised to consume protein intakes in the range of ～1.8–2.7 g kg^?1 d^?1 (or ～2.3–3.1 g kg^?1 FFM) in combination with a moderate energy deficit (?500 kcal) and the performance of some form of resistance exercise. The target level of protein intake within this recommended range requires consideration of a number of case-specific factors including the athlete's body composition, habitual protein intake and broader nutrition goals. Athletes should focus on consuming high-quality protein sources, aiming to consume protein feedings evenly spaced throughout the day. Post-exercise consumption of 0.25–0.3 g protein meal^?1 from protein sources with high leucine content and rapid digestion kinetics (i.e. whey protein) is recommended to optimise exercise-induced muscle protein synthesis. When protein is consumed as part of a mixed macronutrient meal and/or before bed slightly higher protein doses may be optimal.     

Skeletal muscle glycogen concentration and metabolic responses following a high glycaemic carbohydrate breakfast

The purpose of this study was to examine the influence of a carbohydrate-rich meal on post-prandial metabolic responses and skeletal muscle glycogen concentration. After an overnight fast, eight male recreational/club endurance runners ingested a carbohydrate (CHO) meal (2.5 g CHO?·?kg^?1 body mass) and biopsies were obtained from the vastus lateralis muscle before and 3 h after the meal. Ingestion of the meal resulted in a 10.6?±?2.5% (P?<?0.05) increase in muscle glycogen concentration (pre-meal vs post-meal: 314.0?±?33.9 vs 347.3?±?31.3 mmol?·?kg^?1 dry weight). Three hours after ingestion, mean serum insulin concentrations had not returned to pre-feeding values (0 min vs 180 min: 45?±?4 vs 143?±?21 pmol?·?l^?1). On a separate occasion, six similar individuals ingested the meal or fasted for a further 3 h during which time expired air samples were collected to estimate the amount of carbohydrate oxidized over the 3 h post-prandial period. It was estimated that about 20% of the carbohydrate consumed was converted into muscle glycogen, and about 12 % was oxidized. We conclude that a meal providing 2.5 g CHO?·?kg^?1 body mass can increase muscle glycogen stores 3 h after ingestion. However, an estimated 67% of the carbohydrate ingested was unaccounted for and this may have been stored as liver glycogen and/or still be in the gastrointestinal tract.     

Building muscle: nutrition to maximize bulk and strength adaptations to resistance exercise training

Abstract

Several nutritional strategies can optimize muscle bulk and strength adaptations and enhance recovery from heavy training sessions. Adequate energy intake to meet the needs of training and carbohydrate intake sufficient to maintain glycogen stores (>7 g carbohydrate·kg^?1·day^?1 for women; >8 g carbohydrate·kg^?1·day^?1 for men) are important. Dietary protein intake for top sport athletes should include some foods with high biological value, with a maximum requirement of approximately 1.7 g·kg^?1·day^?1 being easily met with an energy sufficient diet. The early provision of carbohydrate (>1 g·kg^?1) and protein (>10 g) early after an exercise session will enhance protein balance and optimize glycogen repletion. Creatine monohydrate supplementation over several days increases body mass through water retention and can increase high-intensity repetitive ergometer performance. Creatine supplementation can enhance total body and lean fat free mass gains during resistance exercise training; however, strength gains do not appear to be enhanced versus an optimal nutritional strategy (immediate post-exercise protein and carbohydrate). Some studies have suggested that β-OH-methyl butyric acid (β-HMB) can enhance gains made through resistance exercise training; however, it has not been compared “head to head” with optimal nutritional practices. Overall, the most effective way to increase strength and bulk is to perform sport-specific resistance exercise training with the provision of adequate energy, carbohydrate, and protein. Creatine monohydrate and β-HMB supplementation may enhance the strength gains made through training by a small margin but the trade-off is likely to be greater bulk, which may be ergolytic for any athlete participating in a weight-supported activity.     

Nutritional intake and body composition changes in a UCI World Tour cycling team during the Tour of Spain

Abstract

The aim of this study was to quantify the food intake of an International Cyclist Union (UCI) World Tour professional cyclist team and to analyse changes in body composition during the Tour of Spain. Nine male professional road cyclists (31.3?±?3.0 years) volunteered to participate in the study. Nutritional data were collected each day throughout the 3-week Tour by two trained investigators who weighed the food ingested by the cyclists. Mean nutritional intake of the cyclists was as follows: carbohydrate, 12.5?±?1.8?g/kg/day of body weight (BW) (65.0?±?5.9%); fat, 1.5?±?0.5 g/kg/day BW (17.9?±?5.6%); and protein, 3.3?±?0.3?g/kg/day BW (17.1?±?1.6%). Intake of all micronutrients, except for folate, vitamin D and potassium (which were 78.7%, 46% and 84% of Recommended Dietary Allowances (RDA), respectively), exceeded the RDA. Height, weight, skinfolds, circumferences and diameters were taken following the guidelines outlined by the International Society for the Advancement of Kinanthropometry. Body density, body fat percentage, muscle mass, total muscle mass and fat mass of the arms and thighs were calculated. Percentage body fat, fat mass and upper arm fat mass significantly decreased (p < .05) after the Tour independent of the equation method used in the calculations. Total muscle mass remained unchanged. Generally, this sample of cyclists consumed more protein and less fat than the recommended amount and had low weight, BMI and fat mass. It is suggested that sports nutritionists design personalised diets in order to maintain a correct proportion of nutrients as well as controlling possible anthropometrical changes that could affect performance.     

Fluid and electrolyte balance in elite male football (soccer) players training in a cool environment

There are few data in the published literature on sweat loss and drinking behaviour in athletes training in a cool environment. Sweat loss and fluid intake were measured in 17 first-team members of an elite soccer team training for 90 min in a cool (5°C, 81% relative humidity) environment. Sweat loss was assessed from the change in body mass after correction for the volume of fluid consumed. Sweat electrolyte content was measured from absorbent patches applied at four skin sites. Mean (?± s) sweat loss during training was 1.69?±?0.45 l (range 1.06?-?2.65 l). Mean fluid intake during training was 423?±?215 ml (44?-?951 ml). There was no apparent relationship between the amount of sweat lost and the volume of fluid consumed during training (r ² = 0.013, P = 0.665). Mean sweat sodium concentration was 42.5?±?13.0 mmol?·?l^?1 and mean sweat potassium concentration was 4.2?±?1.0 mmol?·?l^?1. Total salt (NaCl) loss during training was 4.3?±?1.8 g. The sweat loss data are similar to those recorded in elite players undergoing a similar training session in warm environments, but the volume of fluid ingested is less.     

The addition of whey protein to a carbohydrate–electrolyte drink does not influence post-exercise rehydration

The addition of whey protein to a carbohydrate–electrolyte drink has been shown to enhance post-exercise rehydration when a volume below that recommended for full fluid balance restoration is provided. We investigated if this held true when volumes sufficient to restore fluid balance were consumed and if differences might be explained by changes in plasma albumin content. Sixteen participants lost ~1.9% of their pre-exercise body mass by cycling in the heat and rehydrated with 150% of body mass lost with either a 60 g · L^?1 carbohydrate drink (CHO) or a 60 g · L^?1 carbohydrate, 20 g · L^?1 whey protein isolate drink (CHO-P). Urine and blood samples were collected pre-exercise, post-exercise, post-rehydration and every hour for 4 h post-rehydration. There was no difference between trials for total urine production (CHO 1057 ± 319 mL; CHO-P 970 ± 334 mL; P = 0.209), drink retention (CHO 51 ± 12%; CHO-P 55 ± 15%; P = 0.195) or net fluid balance (CHO ?393 ± 272 mL; CHO-P ?307 ± 331 mL; P = 0.284). Plasma albumin content relative to pre-exercise was increased from 2 to 4 h during CHO-P only. These results demonstrate that the addition of whey protein isolate to a carbohydrate–electrolyte drink neither enhances nor inhibits rehydration. Therefore, where post-exercise protein ingestion might benefit recovery, this can be consumed without effecting rehydration.     

Effect of acute ingestion of β-hydroxybutyrate salts on the response to graded exercise in trained cyclists

Acute ingestion of ketone salts induces nutritional ketosis by elevating β-hydroxybutyrate (βHB), but few studies have examined the metabolic effects of ingestion prior to exercise. Nineteen trained cyclists (12 male, 7 female) undertook graded exercise (8 min each at ～30%, 40%, 50%, 60%, 70%, and 80% VO_2peak) on a cycle ergometer on two occasions separated by either 7 or 14 days. Trials included ingestion of boluses of either (i) plain water (3.8?mL?kg?body mass^?1) (CON) or (ii) βHB salts (0.38?g?kg?body mass^?1) in plain water (3.8?mL?kg body mass^?1) (KET), at both 60 min and 15 min prior to exercise. During KET, plasma [βHB] increased to 0.33?±?0.16?mM prior to exercise and 0.44?±?0.15?mM at the end of exercise (both p?.05). Plasma glucose was 0.44?±?0.27?mM lower (p?.01) 30?min after ingestion of KET and remained ～0.2?mM lower throughout exercise compared to CON (p?.001). Respiratory exchange ratio (RER) was higher during KET compared to CON (p?.001) and 0.03–0.04 higher from 30%VO_2peak to 60%VO_2peak (all p?.05). No differences in plasma lactate, rate of perceived exertion, or gross or delta efficiency were observed between trials. Gastrointestinal symptoms were reported in 13 out of 19 participants during KET. Acute ingestion of βHB salts induces nutritional ketosis and alters the metabolic response to exercise in trained cyclists. Elevated RER during KET may be indicative of increased ketone body oxidation during exercise, but at the plasma βHB concentrations achieved, ingestion of βHB salts does not affect lactate appearance, perceived exertion, or muscular efficiency.     

The influence of carbohydrate and protein ingestion during recovery from prolonged exercise on subsequent endurance performance

Abstract

Ingesting carbohydrate plus protein following prolonged exercise may restore exercise capacity more effectively than ingestion of carbohydrate alone. The objective of the present study was to determine whether this potential benefit is a consequence of the protein fraction per se or simply due to the additional energy it provides. Six active males participated in three trials, each involving a 90-min treadmill run at 70% maximal oxygen uptake (run 1) followed by a 4-h recovery. At 30-min intervals during recovery, participants ingested solutions containing: (1) 0.8 g carbohydrate · kg body mass (BM)^?1 · h^?1 plus 0.3 g · kg^?1 · h^?1 of whey protein isolate (CHO-PRO); (2) 0.8 g carbohydrate · kg BM^?1 · h^?1 (CHO); or (3) 1.1 g carbohydrate · kg BM^?1 · h^?1 (CHO-CHO). The latter two solutions matched the CHO-PRO solution for carbohydrate and for energy, respectively. Following recovery, participants ran to exhaustion at 70% maximal oxygen uptake (run 2). Exercise capacity during run 2 was greater following ingestion of CHO-PRO and CHO-CHO than following ingestion of CHO (P ≤ 0.05) with no significant difference between the CHO-PRO and CHO-CHO treatments. In conclusion, increasing the energy content of these recovery solutions extended run time to exhaustion, irrespective of whether the additional energy originated from sucrose or whey protein isolate.     

Combined metabolic gas analyser and dGPS analysis of performance in cross-country skiing

The purpose of this study was to provide a more detailed analysis of performance in cross-country skiing by combining findings from a differential global positioning system (dGPS), metabolic gas measurements, speed in different sections of a ski-course and treadmill threshold data. Ten male skiers participated in a freestyle skiing field test (5.6?km), which was performed with dGPS and metabolic gas measurements. A treadmill running threshold test was also performed and the following parameters were derived: anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio = 1, onset of blood lactate accumulation and peak oxygen uptake ([Vdot]O_2peak). The combined dGPS and metabolic gas measurements made detailed analysis of performance possible. The strongest correlations between the treadmill data and final skiing field test time were for [Vdot]O_2peak (l?·?min^?1), respiratory exchange ratio = 1 (l?·?min^?1) and onset of blood lactate accumulation (l?·?min^?1) (r = ?0.644 to ??0.750). However, all treadmill test data displayed stronger associations with speed in different stretches of the course than with final time, which stresses the value of a detailed analysis of performance in cross-country skiing. Mean oxygen uptake ([Vdot]O₂) in a particular stretch in relation to speed in the same stretch displayed its strongest correlation coefficients in most stretches when [Vdot]O₂ was presented in units litres per minute, rather than when [Vdot]O₂ was normalized to body mass (ml?·?kg^?1?·?min^?1 and ml?·?min^?1?·?kg^?2/3). This suggests that heavy cross-country skiers have an advantage over their lighter counterparts. In one steep uphill stretch, however, [Vdot]O₂ (ml?·?min^?1?·?kg^?2/3) displayed the strongest association with speed, suggesting that in steep uphill sections light skiers could have an advantage over heavier skiers.     

Caffeine and resistance exercise: the effects of two caffeine doses and the influence of individual perception of caffeine

Abstract

Although caffeine is a widely used ergogenic resource, some information regarding its effects on resistance exercises is still lacking. The objective of the present study was to verify the acute effect of the ingestion of two different doses of caffeine on performance during a session of resistance exercises and to analyze the perception of the subjects in relation to the intake of caffeine. Following a double-blind, randomised, cross-over, controlled, and non-placebo design, 14 trained and healthy men (24.7?±?6.8 years; 79.8?±?9.8?kg; 177.3?±?8.5?cm) performed a training session in chest-press, shoulder-press, and biceps curl exercises (3 sets until exhaustion; 70% 1RM; 3 min rest interval; 2?s for each concentric and eccentric phase) on three non-consecutive days after ingestion of 3?mg.kg^?1 caffeine (CAF3), 6?mg.kg^?1 caffeine (CAF6), or no substance (CON). Subjects were informed that one of the caffeine doses would be placebo. The total number of repetitions performed in CON (93.6?±?22.4) was significantly lower than in CAF3 (108.0?±?19.9, P?=?0.02) and in CAF6 (109.3?±?19.8, P?=?0.03) and there were no differences between caffeine doses. Eight subjects noticed that caffeine was in CAF3 and six in CAF6 and there were no differences in the number of repetitions between sessions in which the subjects perceived and did not perceive caffeine. In conclusion, caffeine doses of 3 or 6?mg.kg^?1 similarly increased performance in resistance upper limb exercises, independent of the subject's perception of substance ingestion.     

Caffeine lowers perceptual response and increases power output during high-intensity cycling

The aim of this study was to determine the effects of caffeine ingestion on a ‘preloaded’ protocol that involved cycling for 2?min at a constant rate of 100% maximal power output immediately followed by a 1-min ‘all-out’ effort. Eleven male cyclists completed a ramp test to measure maximal power output. On two other occasions, the participants ingested caffeine (5?mg?·?kg^?1) or placebo in a randomized, double-blind procedure. All tests were conducted on the participants' own bicycles using a Kingcycle? test rig. Ratings of perceived exertion (RPE; 6–20 Borg scale) were lower in the caffeine trial by approximately 1 RPE point at 30, 60 and 120?s during the constant rate phase of the preloaded test (P?<0.05). The mean power output during the all-out effort was increased following caffeine ingestion compared with placebo (794±164 vs 750±163?W; P?=?0.05). Blood lactate concentration 4, 5 and 6?min after exercise was also significantly higher by approximately 1?mmol?·?l^?1 in the caffeine trial (P?<0.05). These results suggest that high-intensity cycling performance can be increased following moderate caffeine ingestion and that this improvement may be related to a reduction in RPE and an elevation in blood lactate concentration.     

Simulated tennis matchplay in a controlled environment

The aim of this study was to develop an exercise protocol to simulate tennis matchplay on a 'category 2' surface. Match analyses were used to form the basis for the design of the protocol. The protocol involved playing against a tennis ball serving machine. Part A of the protocol comprised 92 min 46 s of simulated tennis matchplay; Part B consisted of continuous hitting to the point of 'volitional fatigue' or when the required hitting frequency for two consecutive ball feeds could no longer be maintained. Ten elite tennis players (5 males, 5 females) volunteered to participate in the study, which was performed on an indoor tennis court (Matchplay?, En-Tout-Cas)?. Their age, body mass and estimated maximal oxygen uptake were as follows: males, 21.7±1.0 years, 73.6±2.6 kg and 58.0±1.7 ml?·?kg^?1?·?min^?1, respectively; females, 21.9±1.3 years, 62.3±2.0 kg and 42.2±0.7 ml?·?kg?·?min^?1, respectively (mean±). Heart rate, change in body mass and time to volitional fatigue were monitored. The heart rate responses of the participants to the simulated matchplay (range: 140-157 beats?·?min^?1, 73-81% peak heart rate) were consistent with the results of previous studies, for 'actual' matchplay. This protocol was successful in simulating similar physiological responses in Part A to 'actual' matchplay on a 'category 2' surface, in a controlled environment; it was also a sensitive evaluation tool of skilled performance in Part B. The current protocol may be used as a baseline protocol for studying the influence of, for example, training and dietary intervention on performance.     

Effect of combined carbohydrate-protein ingestion on markers of recovery after simulated rugby union match-play

Abstract

In this study, we investigated the effect of ingesting carbohydrate alone or carbohydrate with protein on functional and metabolic markers of recovery from a rugby union-specific shuttle running protocol. On three occasions, at least one week apart in a counterbalanced order, nine experienced male rugby union forwards ingested placebo, carbohydrate (1.2 g · kg body mass^?1 · h^?1) or carbohydrate with protein (0.4 g · kg body mass^?1 · h^?1) before, during, and after a rugby union-specific protocol. Markers of muscle damage (creatine kinase: before, 258 ± 171 U · L^?1 vs. 24 h after, 574 ± 285 U · L^?1; myoglobin: pre, 50 ± 18 vs. immediately after, 210 ± 84 nmol · L^?1; P < 0.05) and muscle soreness (1, 2, and 3 [maximum soreness = 8] for before, immediately after, and 24 h after exercise, respectively) increased. Leg strength and repeated 6-s cycle sprint mean power were slightly reduced after exercise (93% and 95% of pre-exercise values, respectively; P < 0.05), but were almost fully recovered after 24 h (97% and 99% of pre-exercise values, respectively). There were no differences between trials for any measure. These results indicate that in experienced rugby players, the small degree of muscle damage and reduction in function induced by the exercise protocol were not attenuated by the ingestion of carbohydrate and protein.     

The creatine content of Creatine Serum™ and the change in the plasma concentration with ingestion of a single dose

Three samples of Creatine Serum? ATP Advantage from Muscle Marketing USA, Inc. were assayed for creatine by two different techniques by four independent laboratories, and for creatinine by two different techniques by two laboratories. A further sample was assayed for phosphorylcreatine. Dry weight and total nitrogen were also analysed. Six male volunteers ingested in random order, over 3 weeks: (A) water; (B) 2.5?g creatine monohydrate (Cr?·?H₂O) in solution; and (C) 5?ml Creatine Serum? (reportedly containing an equivalent amount of Cr?·?H₂O). Blood samples were collected before and up to 8?h after each treatment and plasma was analysed for creatine and creatinine. Eight-hour urine samples were analysed for creatine. Ingestion of 2.5?g creatine monohydrate in solution resulted in a significant increase in plasma creatine (from 59.1±11.8?μmol?·?l^?1 to 245.3±74.6?μM μmol?·?l^?1; mean±s) and urinary creatine excretion. No increase in plasma or urinary creatine or creatinine was found on ingestion of Creatine Serum? or water. Analysis showed 5?ml of Creatine Serum? to contain <10?mg Cr?·?H₂O and approximately 90?mg creatinine. Phosphorylcreatine was not detectable and only a trace amount of phosphorous was present. Total nitrogen analysis ruled out significant amounts of other forms of creatine. We conclude that the trace amounts of creatine in the product would be too little to affect the muscle content even with multiple dosing.     

A single session of resistance exercise does not reduce postprandial lipaemia

This study investigated the effect of a single session of resistance exercise on postprandial lipaemia. Eleven healthy normolipidaemic men with a mean age of 23 (standard error = 1.4) years performed two trials at least 1 week apart in a counterbalanced randomized design. In each trial, participants consumed a test meal (1.2?g fat, 1.1?g carbohydrate, 0.2?g protein and 68 kJ?·?kg^?1 body mass) between 08.00 and 09.00?h following a 12?h fast. The afternoon before one trial, the participants performed an 88?min bout of resistance exercise. Before the other trial, the participants were inactive (control trial). Resistance exercise was performed using free weights and included four sets of 10 repetitions of each of 11 exercises. Sets were performed at 80% of 10-repetition maximum with a 2?min work and rest interval. Venous blood samples were obtained in the fasted state and at intervals for 6?h postprandially. Fasting plasma triacylglycerol (TAG) concentration did not differ significantly between control (1.03?±?0.13?mmol?·?l^?1) and exercise (0.94?±?0.09?mmol?·?l^?1) trials (mean?± standard error). Similarly, the 6?h total area under the plasma TAG concentration versus time curve did not differ significantly between the control (9.84?±?1.40?mmol?·?l^?1?·?6?h^?1) and exercise (9.38?±?1.12?mmol?·?l^?1?·?6?h^?1) trials. These findings suggest that a single session of resistance exercise does not reduce postprandial lipaemia.     

Whole-body vibration can reduce calciuria induced by high protein intakes and may counteract bone resorption: A preliminary study

Abstract

Excess protein intake can adversely affect the bone via an increase in calcium excretion, while suitable mechanical loading promotes osteogenesis. We therefore investigated whether vibration exposure could alleviate the bone mineral losses associated with a metabolic acidosis. Ten healthy individuals aged 22 – 29 years (median = 25) underwent three 5-day study periods while monitoring their dietary intake. The study consisted of recording the participants' usual dietary intake for 5 consecutive days. Participants were then randomly divided into two groups, one of which received a protein supplement (2 g · kg^?1 body mass · day^?1; n = 5) and the other whole-body low-magnitude (3.5 g), low-frequency (30 Hz) mechanical vibration (WBV) delivered through a specially designed vibrating plate for 10 min each day (n = 5). Finally, for the third treatment period, all participants consumed the protein supplement added to their normal diet and were exposed to WBV exercise for 10 min per day. Daily urine samples were collected throughout the experimental periods to determine the excretion of calcium, phosphate, titratable acid, urea, and C-telopeptide. As expected, when the participants underwent the high protein intake, there was an increase in urinary excretion rates of calcium (P < 0.001), phosphate (P < 0.003), urea (P < 0.001), titratable acid (P < 0.001), and C-telopeptide (P < 0.05) compared with baseline values. However, high protein intake coupled with vibration stimulation resulted in a significant reduction in urinary calcium (P = 0.006), phosphate excretion (P = 0.021), and C-telopeptide (P < 0.05) compared with protein intake alone, but did not affect titratable acid and urea output. The participants showed no effect of WBV exercise alone on urinary excretion of calcium, phosphate, urea, titratable acid, or C-telopeptide. The results indicate that vibration stimulation can moderate the increase in bone resorption and reduction in bone formation caused by a metabolic acidosis.     

Carbohydrate intake and ketosis in self-sufficient multi-stage ultramarathon runners

ABSTRACT

Ultra-endurance athletes accumulate an energy deficit throughout their events and those competing in self-sufficient multi-stage races are particularly vulnerable due to load carriage considerations. Whilst urinary ketones have previously been noted in ultra-endurance exercise and attributed to insufficient carbohydrate (CHO) availability, not all studies have reported concomitant CHO intake. Our aim was to determine changes in blood glucose and β-hydroxybutyrate concentrations over five days (240 km) of a self-sufficient multi-stage ultramarathon in combination with quantification of energy and macronutrient intakes, estimated energy expenditure and evaluation of energy balance. Thirteen runners (8 male, 5 female, mean age 40 ± 8 years) participated in the study. Glucose and β-hydroxybutyrate were measured every day immediately post-running, and food diaries completed daily. CHO intakes of 301 ± 106 g·day^?1 (4.3 ± 1.8 g·kg^?1·day^?1) were not sufficient to avoid ketosis (5-day mean β-hydroxybutyrate: 1.1 ± 0.6 mmol.L^?1). Furthermore, ketosis was not attenuated even when CHO intake was high (9 g·kg^?1·day^?1). This suggests that competing in a state of ketosis may be inevitable during multi-stage events where load reduction is prioritised over energy provisions. Attenuating negative impacts associated with such a metabolic shift in athletes unaccustomed to CHO and energy restriction requires further exploration.