Protein-enhanced sport drinks

Endurox R4 and Accelerade

What it is
Both Accelerade and Endurox R4 are protein-enhanced sport drinks that contain a formula of carbohydrate and protein in a ratio of 4 to 1 (for every 4 grams of
carbohydrate, there is 1 gram of protein). The benefits of Accelerade are believed to come when it is consumed during exercise. On the other hand, being a
more concentrated blend of nutrients, Endurox R4 is more suited for recovery. Both contain whey protein, sodium, potassium and various combinations of
carbohydrate including simple sugars, complex carbohydrates like maltodextrin and a disaccharide called trehalose. Accelerade also contains a little vitamin E and
calcium and a version containing caffeine can also be purchased. There is a gel version called AccelGel and it contains more vitamin C and E (100% RDA) than
the powder form. Endurox R4 contains large amounts of vitamin C (780% RDA), vitamin E (1330% RDA), L-glutamine (an amino acid) and a little calclium and
magnesium.

Here's how these products compare nutritionally to the traditional carbohydrate sport drink, Gatorade (check out my review on antioxidants to find out more about
vitamins C and E and their effects on performance and recovery).

                                      Gatorade        Accelerade        AccelGel        Endurox R4
Serving                                8 fl oz             8 fl oz              1 pack           2 scoops
Calories                                 50                  80                    100                270
Carbohydrate                        14 g               15 g                   20 g              52 g
Fat                                        0                     0                       0                  0
Protein                                   0                   4 g                    5 g               13 g
Sodium                               110 mg          120 mg            100 mg           210 mg
Potassium                            30 mg            15 mg              50 mg           120 mg
Vitamin E                               0                  25%                 100%            1330%
Vitamin C                               0                     0                   100%             780%
Magnesium                            0                     0                      0                 60%
Calcium                                  0                   2%                    0                10%
L-Glutamine                            0                    0                      0                420 mg

What it costs
Accelerade powder purchased in a container of 15 servings sells for about $15, about $1 per serving. I found that the larger the container (as much as 60
servings),is cheaper at about 50 cents per serving. AccelGel packets are a bit more expensive at $32 for a package of 24 gel packs, about $1.33 per serving.
Endurox R4 can be purchased in 2 or 4 lb containers. The 2 lb contains 14 servings and sells for about $26, a little less than $2 a serving. I purchased a package
of Endurox and a package of Accelerade (each one serving) at a bicycle shop. The Endurox cost $3 and the Accelerade was $2. In comparison, a 3-lb container
of Gatorade powder, about 100 servings, costs about $6-7 in the grocery store, about 15 cents per serving.

The taste test
When it comes to sport drinks, taste preference usually wins out. While paddling, I prefer Gatorade, a bit on the diluted side. Accelerade is fine, but it has a hint of
"metallic" or medicine-like taste that is typical of protein drinks. It's about as sweet tasting as Gatorade (they contain the same amount of carbohydrate) and I
didn't mind it too much. If I allow it to get too warm, my tolerance for Accelerade decreases dramatically. I have yet to try AccelGel. As for the Endurox, I would
much rather eat a turkey sub (which would provide me similar carbohydrate and protein quantities) than drink Endurox. But, the convenience of Endurox during
paddling trips makes it a better option. Unfortunately, I did not like the taste of it, as is the case with so many protein drinks. The whey protein adds a heaviness
or medicine-like taste to the drink that I cannot tolerate in large quantities. If it is more convenient to drink than to eat a turkey sub, by all means, drink it. The
advantage of the Endurox drink over the turkey sub is that you are also replacing fluids. You may also believe the other advantages are that Endurox contains
vitamins C and E, as well as L-glutamine. I review antioxidant supplements in another article, check that out to find out more about the evidence for their effects
on performance and recovery.

The benefits of protein
In addition to glycogen resynthesis, the recovery period is associated with increased muscle protein turnover (both synthesis and breakdown). For net protein
synthesis to occur during recovery from exercise, adequate protein must be consumed. Similar to carbohydrate, optimal results occur when protein is ingested
immediately following exercise and in frequent intervals during the first 4-6 hours. It is also important that the protein ingested contains all 9 essential amino acids,
with or without other nonessential amino acids (somewhere on the label, it should state that all essential amino acids are included). The effects of carbohydrate
ingested with protein may or may not have an added effect on protein synthesis.

There is also some evidence that protein can help glycogen resynthesis. Combined, carbohydrate and protein elicit a similar to greater insulin response than
carbohydrate alone; thus, protein may assist in getting glucose into the muscle for subsequent storage during recovery. Numerous studies have investigated the
combined effects of carbohydrate and protein on glycogen synthesis during recovery and the results are somewhat conflicting. Several studies did not observe an
added effect from protein and found no difference between carbohydrate alone and combined carbohydrate and protein. What appears to be similar among these
studies is that the amount of carbohydrate ingested was considered to be optimal for maximizing carbohydrate stores (> 1 g/kg/hr) and ingested at frequent
intervals (every 30 or 60 min during 4 to 6 hr periods). On the other hand, other studies have shown an added effect of combining carbohydrate with protein
intake compared to carbohydrate alone. However, these studies differ from the previous in that the carbohydrate ingested was below optimal to begin with. The
fact that adding protein had no added benefit is not necessarily a negative for protein; rather, it can be concluded that protein adequately replaces carbohydrate for
glycogen resynthesis, possibly through its effects on insulin and glucose uptake.

The real evidence, protein and carbohydrate during performance
Of four studies that tested the effects of added protein to a carbohydrate supplement, only three measured performance. The results of these studies are
conflicting. The first, Ivy et al, used an intermittent exercise intensity protocol to test performance. While the intensity performed was controlled to test time to
fatigue (TTF), the intensity was varied in a pre-determined way such that athletes performed 3 or 8 minute intervals at 75% of maximum capacity followed by 3 or
8 minute intervals at 45% of maximum capacity for 180 minutes. This was followed by an intensity of 85% of maximum until fatigue. Athletes performed this
protocol on three occasions. During two trials, athletes were given a 7.75% carbohydrate solution (CHO) and for one of these trials, 1.94% protein was added
(CHO+PRO). A third trial was performed with a placebo (no calories). Supplements were given in 200 ml every 20 minutes during each trial. The amount of
carbohydrate was approximately 45 grams each hour, within the recommended 30 to 60 g/hr. Protein intake was approximately 11 grams per hour. Compared
to placebo, TTF was improved by 55% with CHO. More importantly, CHO+PRO improved performance by 39% above CHO alone.

It should be mentioned that there were only 9 male athletes in the study and 2 of them showed no improvement with CHO compared to placebo. Two athletes
showed no improvements with CHO+PRO compared to CHO and in fact, one performed better with the CHO. I like the fact that these investigators reported the
individual variability in response because this is something that is often disregarded as long as the average results are statistically significant. If you go by the
numbers, 1 out of 5 athletes would not benefit from the addition of protein to a carbohydrate supplement. Further, you could also say that 1 out of 5 athletes do
not benefit from carbohydrate supplementation. And, since TTF was used instead of a time trial, you could also say that it isn’t the most relevant assessment of
the supplement's effect on performance since athlete do not win according to time to fatigue.

Another study, Van Essen et al, reported different results from the previous study. These investigators used a self-paced time trial to assess performance, a more
real-life test. For this study, athletes cycled on an ergometer while following a software program that simulated a race time trial. The time trial consisted of four
laps of a 20-km course that was mostly flat to rolling terrain, with some hills at maximal grade of 4%. Athletes performed this time trial 3 times: placebo, CHO
(6% solution) and CHO+PRO (6% carbohydrate solution + 2% protein). The liquid was consumed in 250 ml every 15 minutes for approximately 60 g
carbohydrate each hour. The investigators reported at 4.4% improvement in time during both CHO trials compared to placebo, with no difference in time between
CHO and CHO+PRO. Nine out of 10 athletes showed improvement during the CHO trials compared to placebo, a higher rate than the Ivy et al study. More
importantly, there was no difference in performance between CHO alone and CHO+PRO.

Saunders et al tested the effects of a carbohydrate & protein supplement (formulated to a 4:1 carbohydrate to protein ratio) compared to a carbohydrate
supplement on two TTF tests performed 12-15 hr apart. Performance was assessed during both TTF tests. Supplements were ingested every 15 minutes during
and within 30 minutes following the first TTF. The supplements ingested contained 7.3% carbohydrate consumed in an hourly quantity equivalent to about ½ liter
of fluid and a carbohydrate intake of 37 grams, well within the recommended 30 to 60 g per hour. Following the test, about ¾ liter of fluid containing about 50
grams of carbohydrate was consumed. During the carbohydrate + protein trial, 1.8% protein was added to the carbohydrate in a quantity that provided
approximately 9 grams of protein each hour during the test and about 13 grams during the 30 minutes following the test. The investigators observed improved
performance during both TTF tests with the carbohydrate and protein supplements. Time to fatigue increased 29% and 40% during the first and second tests,
respectively, compared to CHO alone.

Why did one study not see an effect of added protein while 2 studies did? Differences between Van Essen et al study and the other two could be due to the
different performance protocols used (TTF vs time trial) and the different amounts of carbohydrates ingested between studies. Van Essen et al used a time trial,
which is more like an athlete’s competition and has been shown to be very reproducible. Further, their athletes consumed more carbohydrates than did the
athletes in the other two studies. However, the carbohydrate intake in the other two studies was well within the recommended amount. From these results, one
could conclude that the addition of protein has no added benefit on performance when relatively high amounts of carbohydrates are ingested during exercise. The
benefits of protein in Ivy et al and Saunders et al studies were likely because the protein made up for some absent carbohydrate calories.

The bottomline
Although few studies have investigated this question, it appears so far that the addition of protein to optimal amounts of carbohydrates may or may not have
beneficial effects on endurance performance, depending on the amount of CHO consumed. However, more work must be done before we can definitively
answer this question. For instance, we don’t know what would happen during very prolonged exercise (> 5 hrs); however, we do know that adding protein to a
carbohydrate supplement improves whole body protein balance during 6 hrs of exercise (Koopman et al). What effect this has on performance remains to be
seen. While companies continue to sell their patented carbohydrate:protein mixtures in the name of performance enhancement, the jury is still out as to whether
these are truly better than plain old carbohydrates. For the athlete, it may come down to a simple taste choice, either consume 60 g of carbohydrates each hour,
or consume fewer carbohydrates (45 g) and replace the rest with protein (15 g).

The real evidence, protein and carbohydrate during recovery
How is full recovery measured? When does an athlete know that he or she is fully recovered? For the athlete, the best way to access recovery is through
performance. If an athlete is not adequately recovered, performance will suffer. In the lab, recovery has been measured in various ways, one of which is to
measure muscle glycogen stores over a period of recovery time. Another method is to assess the repair of exercise-induced muscle injury. To do this, certain
enzyme levels that serve as markers for muscle damage or a rating scale for muscle soreness is often used to assess individual responses to muscle injury. Yet
another way to determine the success of recovery is by assessing exercise performance following a period of recovery. The performance studies address the
question: “Will this supplement help me recovery more quickly and thus, help maintain my performance levels?”

There is little doubt that ingestion of carbohydrate during recovery will improve subsequent performance. This has been demonstrated repeatedly in studies and
appears to be associated with glycogen restorage during recovery. Adding protein to the carbohydrate supplements may also have benefits for the athlete.
These benefits are associated with increased rate of glycogen resynthesis when added to a suboptimal amount of carbohydrate, increased protein synthesis and a
reduction in exercise-induced muscle injury. With these effects in mind, carbohydrate combined with protein may be better than carbohydrate alone when it
comes to recovery and subsequent exercise performance.

To get to the heart of the matter, five studies have attempted to determine whether or not a combination of carbohydrate and protein is more effective than
carbohydrate alone on improving exercise performance following a period of recovery from exhaustive exercise. In all of these studies, at least two trials are
performed, one with only carbohydrate ingested and the other with carbohydrate + protein. Some studies also included a placebo trial.

When deciding on the supplements and amounts consumed, investigators have two choices; isocaloric or isocarbohydrate. Isocaloric means that the amount
of calories consumed during each trial is controlled. For instance, the total grams consumed each hour during recovery may be set at 1 gram per kilogram body
weight (1 g/kg). In one trial, .6 g/kg of carbohydrate is consumed with .4 g/kg protein, while in the other trial 1 g/kg of carbohydrate is consumed. Basically, some
of the calories from carbohydrate are being replaced with protein. As a result, isocaloric means that the amount of carbohydrate consumed will differ between
trials while the total calories consumed will be similar between trials.

The isocarbohydrate studies control for the amount of carbohydrate, but not the calories. For instance, in one trial, athletes may receive 1 g/kg of carbohydrate
each hour and in the other trial receive the same amount of carbohydrate but with .4 g/kg of protein added. Thus, the carb+protein trial provides a greater amount
of calories. The amount of carbohydrate can be set at the minimum amount necessary for optimal glycogen recovery, which appears to be approximately 1.2
g/kg/hr. In these studies, any benefit from adding protein would be above the optimal benefit provided by carbohydrate.

Three isocaloric studies that measured performance following a recovery period are in agreement on one thing: there was no additional benefit of replacing some
carbohydrate with protein compared to carbohydrate alone. Berardi et al measured performance among cyclists during a second 60-min time trial performed after
6 hrs of recovery from the first 60-min time trial. During recovery, athletes were fed either a mixture of carbohydrate and protein, carbohydrate alone or a placebo
(no energy) immediately following, 1 hr and 2 hr after the first time trial. A meal consisting of a mixture of protein, carbohydrate and fat was consumed at 4 hr.
Interestingly, the carbohydrate and protein trial resulted in a higher rate of glycogen resynthesis during recovery; despite this, performance was not improved.

Romano et al compared carbohydrate supplement to Accelerade and Endurox, both formulated with carbohydrate and protein. In this study, athletes performed a
time-to-fatigue trial at 70% of their maximum capacity followed by 24 hrs of recovery after which they performed a second time-to-fatigue trial at 80% of
maximum capacity. During the first ride, athletes were given either a 9.3% carbohydrate solution or the Accelerade which consists of 7.5% carbohydrate and
1.8% protein every 15 minutes. The total amount of carbohydrate provided during the ride was 60 g/hr for the carbohydrate trial and 45 g/hr for the Accelerade
trial. Immediately following the ride, a recovery drink was provided, either 18.6% carbohydrate or Endurox drink which consists of 15% carbohydrate and 3.6%
protein. The athletes returned 24 hr later to perform the second ride. Similar to Berardi et al, there was no improvement in performance when the carbohydrate
and protein mixture drinks were consumed. However, there was evidence that exercise-induced muscle damage was reduced with the carbohydrate and protein
drinks, as determined by enzyme levels measured in blood samples.

Similar to the previous two studies, Millard et al did not observe performance benefits from a carbohydrate and protein mixture consumed during recovery.
Runners began the trials with a 21-km time trial followed by 2 hr of recovery and a time-to-fatigue run at 90% of maximum capacity. Twenty four hours later, the
runners completed a 5-km time trial. During the 2-hr recovery period, athletes were provided either a 6% carbohydrate drink (Gatorade), 10% carbohydrate drink,
or a 8% carbohydrate + 2% protein drink, provided in amounts equivalent to 1 g/kg/hr. They were also give ¾ liter of a solution following the 90% time-to-fatigue
trial. Among the 3 trials, there were no differences in performance, for both the time-to-fatigue run and the 5-km time trial. However, athletes reported less
muscle soreness following the carbohydrate and protein solution.

From the isocaloric studies, the results can be interpreted to mean that when protein replaces some of the carbohydrate, there is no added benefit in terms of
performance; however, it can also be interpreted to mean that protein adequately replaces carbohydrate in terms of recovery and performance. Consuming the
protein in place of some carbohydrate may also reduce exercise-induced muscle injury, but this needs to be studied further before a final answer can be provided.
The bottomline from these studies is that an athlete has some choices for foods or supplements during his or her recovery period if they are concerned about
getting adequate carbohydrates. Eating a Subway turkey breast would be just as beneficial as consuming a Power Bar.

The two isocarbohydrate studies differ in their results. Saunders et al, discussed earlier, observed a 40% improvement during a TTF trial performed following 12-
15 hr of recovery from another TTF trial. Supplements were ingested every 15 minutes during and within 30 minutes following the first TTF. The supplements
ingested contained 7.3% carbohydrate consumed in an hourly quantity equivalent to about ½ liter of fluid and a carbohydrate intake of 37 grams, well within the
recommended 30 to 60 g per hour. Following the test, about ¾ liter of fluid containing about 50 grams of carbohydrate was consumed. During the carbohydrate
+ protein trial, 1.8% protein was added to the carbohydrate in a quantity that provided approximately 9 grams of protein each hour during the test and about 13
grams during the 30 minutes following the test.

Betts et al tested a carbohydrate and protein mixture consumed during 4 hrs of recovery from a 90-min run at 70% maximum capacity. Performance was
evaluated during a TTF trial performed at 85% of maximum capacity. Athletes were provided a 9.3% carbohydrate solution either with or without 1.5% protein
added. Solutions were consumed every 30 min in volumes that provided 1.2 g/kg/hr carbohydrate. In another study, athletes consumed the same solutions but
at a rate of .8 g/kg/hr of carbohydrate. TTF trial run performance did not differ between carbohydrate and carbohydrate + protein trials, indicating that protein
added to adequate carbohydrate had no additional benefits to performance.

The bottomline
When performance is evaluated following a recovery period, protein can adequately replace some carbohydrates, but may or may not result in improved
performance beyond the effects of adequate carbohydrate intake. In other words, if you consume the optimal amount of carbohydrate during recovery, adding
protein may not have beneficial effects on performance. On the other hand, it is interesting that the addition of protein to a carbohydrate solution may benefit
athletes by reducing muscle injury. Given that protein ingestion increases net protein synthesis following exercise, this is likely one of the effects. But how this
subsequently affects performance appears to be controversial. The conflicting results on performance may have more to do with the lack of reliability among
these tests. On the other hand, a 40% improvement is substantial and well beyond day-to-day variability experienced by an individual athlete. Perhaps the true
test of protein's effects are during multi-day strenuous races where protein breakdown is substantial as a result from prolonged exercise and chronic negative
energy balance.

In summary

Consuming adequate carbohydrates before, during and after exercise is beneficial to performance compared to no calories consumed.
Replacing some carbohydrates with protein during exercise and immediately following exercise can adequately replace carbohydrate’s effect on performance
and recovery.
Replacing some carbohydrates with protein immediately following exercise can adequately replace carbohydrate’s effect on glycogen synthesis.
Adding protein to optimal levels of carbohydrate during exercise and immediately following exercise has no additional benefit to performance or glycogen
synthesis.
Adding protein to a carbohydrate supplement may reduce exercise-induced muscle injury symptoms.
Adding protein to a carbohydrate supplement immediately following exercise will improve protein synthesis.

The final score for Accelerade and Endurox out of a possible 5 points: 4.5

References
Berardi et al. Postexercise muscle glycogen recovery enhanced with a carbohydrate-protein supplement. Med. Sci. Sports Exerc. 38: 1106-1113, 2006.

Betts et al. Recovery of endurance running capacity: effect of carbohydrate-protein mixtures. Int. J. Sport Nutr. Exerc. Metab. 15: 590-609, 2005.

Carrithers et al. Effects of postexercise carbohydrate-protein feedings on muscle glycogen restoration. J. Appl. Physiol. 88: 1976-1982, 2000.

Fallowfield et al. The influence of ingesting a carbohydrate-electrolyte beverage during 4 hours of recovery on subsequent endurance capacity. Int. J. Sport Nutr.
5: 285-299, 1995.

Ivy J. et al. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J. Appl. Physiol. 93: 1337-1344, 2002.

Ivy J. et al. Effect of a carbohydrate-protein supplement on endurance performance during exercise of varying intensity. Int. J. Sport Nutr. 13: 382-395, 2003.

Jentjens & Jeukendrup. Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Med. 33: 117-144, 2003.

Koopman et al. Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise. Am J. Physiol. 287: E712-E720,
2004.

Lemon P. Beyond the zone: protein needs of active individuals. J. Amer. Coll Nutrition. 19:513S-521S, 2000.

Millard-Stafford M. et al. Recovery from run training: efficacy of a carbohydrate-protein beverage? Int. J. Sport Nutr. Exerc. Metab. 15: 610-624, 2005.

Romano-Ely B. C. et al. Effect of an isocaloric carbohydrate-protein-antioxidant drink on cycling performance. Med. Sci. Sports Exerc. 38: 1608-1616, 2006.

Saunders M. J. et al. Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage. Med. Sci. Sports Exerc. 36: 1233-1238, 2004.

Van Essen & Gibala. Failure of protein to improve time trial performance when added to a sports drink. Med. Sci. Sports Exerc. 38: 1476-1483, 2006.

Wong et al. Effects of ingesting a large volume of carbohydrate-electrolyte solution on rehydration. Int. J. Sport Nutr. Exerc. Metab. 10: 375-393, 2000.

Written in 2008

Back to HOME

For optimal glycogen refueling during recovery, follow these guidelines.
Carbohydrate alone	Carbohydrate + Protein
1.2 g/kg body weight immediately following exercise. > 1 g/kg/hr during the 4-6 hr period following exercise, consumed every 30 to 60 minutes.	0.8 g/kg body weight of carbohydrate + 0.4 g/kg body weight of protein immediately following exercise and continuing this during the first 4-6 hr period, at intervals 30 to 60 minutes.

Two strategies for adding protein (PRO) to carbohydrate (CHO) intake during recovery periods
Isocaloric	Isocarbohydrate
The same: Total grams (calories) consumed every hr 1.2 g CHO/kg body weight vs 0.8 g CHO/kg body weight + 0.4 g PRO/kg body weight Different: Total CHO consumed 1.2 g CHO/kg body weight vs 0.8 g CHO/KG body weight Study results: no added benefits of PRO on performance following a recovery period.	The same: Total grams CHO consumed every hr 1.2 g CHO/kg body weight vs 1.2 g CHO/kg body weight + 0.4 g PRO/kg body weight Different: Total calories consumed 1.2 g CHO/kg body weight vs 1.6 g CHO +PRO/kg body weight Study results: no added benefits of PRO on performance following a recovery period.