Monday, October 25, 2010

50% Lower cal MIXED carb with Moderate Protein better than Higher Carb alone for Greater Endurance Want to stay out on your bike longer? There's a nice new study that has entered the energy drink fray, returning to the question of what's a ratio of protein to carbs that's optimal? In this case one measure of optimal is Time to Exhaustion or TTE. Also checked is optimal for what level of effort (below or near ventilatory threshold or VT). Turns out that half the calories (of the right blend of carb types with protein) can give greater, go longer, harder results.

The authors of this study manipulate a couple of variables in interesting ways. First, they decide they want to reduce the total amount of calories in the beverage - so lower the carbs in particular. But then, they want to look at a carb blend rather than just one carb type. So their target is a maltodextrin-dextrose-fructose blend. And then they want to add in some protein, since many studies have shown previously that throwing in some protein seems to have a better endurance effect than carb alone (a few recent examples cited below)

The authors say they were motivated by the desires of cyclists who actually want a lower cal beverage for restoration while on a ride. That makes the question simple: can a better blend of the basics achieve the same or better effect than a higher cal beverage for endurance?

That these authors are asking this question at two distinct ventelatory threshold percentages is also pretty unique.

Here's the abstract:
J Strength Cond Res. 2010 Oct;24(10):2577-86.
The effect of a low carbohydrate beverage with added protein on cycling endurance performance in trained athletes.

Ferguson-Stegall L, McCleave EL, Ding Z, Kammer LM, Wang B, Doerner PG, Liu Y, Ivy JL.

Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, USA.

Ingesting carbohydrate plus protein during prolonged variable intensity exercise has demonstrated improved aerobic endurance performance beyond that of a carbohydrate supplement alone. The purpose of the present study was to determine if a supplement containing a mixture of different carbohydrates (glucose, maltodextrin, and fructose) and a moderate amount of protein given during endurance exercise would increase time to exhaustion (TTE), despite containing 50% less total carbohydrate than a carbohydrate-only supplement. We also sought post priori to determine if there was a difference in effect based on percentage of ventilatory threshold (VT) at which the subjects cycled to exhaustion. Fifteen trained male and female cyclists exercised on 2 separate occasions at intensities alternating between 45 and 70% VO2max for 3 hours, after which the workload increased to ∼74-85% VO2max until exhaustion. Supplements (275 mL) were provided every 20 minutes during exercise, and these consisted of a 3% carbohydrate/1.2% protein supplement (MCP) and a 6% carbohydrate supplement (CHO). For the combined group (n = 15), TTE in MCP did not differ from CHO (31.06 ± 5.76 vs. 26.03 ± 4.27 minutes, respectively, p = 0.064). However, for subjects cycling at or below VT (n = 8), TTE in MCP was significantly greater than for CHO (45.64 ± 7.38 vs. 35.47 ± 5.94 minutes, respectively, p = 0.006). There were no significant differences in TTE for the above VT group (n = 7). Our results suggest that, compared to a traditional 6% CHO supplement, a mixture of carbohydrates plus a moderate amount of protein can improve aerobic endurance at exercise intensities near the VT, despite containing lower total carbohydrate and caloric content.
So, great, a lower cal (50% lower) blend of carbs and protein (about 2:1) of their mixed carb +pro beverage does just as well as a higher cal protein drink when  moseying along, BUT it kicks statistically significant butt when going near or at VT.

What's rather interesting to me is not only the lower calories but the carb/protein ratio. Previously, it was asserted that a 4 to 1 ratio of carbs to protein was best for endurance types doing post exercise recovery. Now, these folks aren't really assessing recovery; they're looking at being able to go longer and greater intensity on the bike. And for that a 2:1 ratio of their mixed carb blend is doing the job.

There was speculation back in a 2009 chocolate milk study (thomas09) that checking similar markers, the reason that choclate milk and just plain carb (gatorade) beverage did better than a 4:1 custom drink (endurox) is that chocolate milk has a diverse mix of carbs. Indeed, the authors site another relatively recent study  by Currell  and Jeukendrup (currell08) that looked at the role of blending carb types and saw an 8% boost in using blended rather than single source carbs for cycling time trials. Similarly a carb/protein blend seems to mean better muscle protection (saunders07).

So, that's good evidence to say let's just go with a blend rather than re-validating that carb blends are better.

One might ask why there were only two treatment conditions in the study: a CHO only drink at 6%, a mixed carb plus protein drink at half the calories. What about the mixed carb drink at half the calories, since we see from related research that mixed is better than straight carbs? The researchers had already done the related studies. They state:
Martinez-Lagunas et al.  recently compared the effects of a 4.5% CHO plus 1.15% PRO, and a 3% CHO plus 0.75% PRO beverage, to a traditional 6% CHO beverage and found that there was no difference in the times to exhaustion between the treatments. This suggests that the efficacy of the supplements was maintained despite the reduction in total CHO and total energy content with the substitution of a small amount of protein (ml). Based on these findings, we sought to determine if a lower CHO, lower calorie beverage containing a moderate amount of protein could be optimized using a mixture of CHO sources (glucose [dextrose], maltodextrin, and fructose) rather than a single CHO (dextrose).
Another nice thing about the study is that the researchers used trained athletes, which means that we're not having to account for level of fitness as a variable.  Even food logs for the three days leading up to the trial were assessed. The finding - 50% fewer calories  - for extended time to exhaustion when working hard is compelling. As the authors note:
The present investigation demonstrates that consuming a beverage containing a mixture of different carbohydrates, a moderate amount of protein and fewer calories than a traditional, higher single-carbohydrate supplement during endurance exercise can extend exercise TTE, especially when exercising at or below the VT.
Sometimes less really is more.


CURRELL, K., & JEUKENDRUP, A. (2008). Superior Endurance Performance with Ingestion of Multiple Transportable Carbohydrates Medicine & Science in Sports & Exercise, 40 (2), 275-281 DOI: 10.1249/mss.0b013e31815adf19
Ferguson-Stegall L, McCleave EL, Ding Z, Kammer LM, Wang B, Doerner PG, Liu Y, & Ivy JL (2010). The effect of a low carbohydrate beverage with added protein on cycling endurance performance in trained athletes. Journal of strength and conditioning research / National Strength & Conditioning Association, 24 (10), 2577-86 PMID: 20733521

Martínez-Lagunas V, Ding Z, Bernard JR, Wang B, & Ivy JL (2010). Added protein maintains efficacy of a low-carbohydrate sports drink. Journal of strength and conditioning research / National Strength & Conditioning Association, 24 (1), 48-59 PMID: 19924010

Saunders MJ, Luden ND, & Herrick JE (2007). Consumption of an oral carbohydrate-protein gel improves cycling endurance and prevents postexercise muscle damage. Journal of strength and conditioning research / National Strength & Conditioning Association, 21 (3), 678-84 PMID: 17685703

Thomas K, Morris P, & Stevenson E (2009). Improved endurance capacity following chocolate milk consumption compared with 2 commercially available sport drinks. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 34 (1), 78-82 PMID: 19234590

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Hanley Tucks said...

In other words,

"drink milk."

Or if you want to be more complicated,

"Usually, ordinary food and drink is better than a more expensive version in a glossy packet."

Mike T Nelson said...

It is an interesting study and I love the work from Ivy's lab, but I am not sold yet.

They cite research showing a mixed CHO is better, but I have doubts that adding protein DURING training will make much of a difference (earlier data confirms this too).

I agree that IF the study holds up in a TIME TRIAL (note, most studies use exercise to exhaustion, but they do not always match a time trial/race simulated study), less calories and more performance is great! We can already due that by shifting fuel usage during exercise to more fat, esp since they are staying under VT. Make them more metabolically flexible to burn fat at a higher intensities, esp since this was a long ride.

Most trained athletes are so used to incoming carbs, that their bodies run primarily on them when they could be burning fat, so they get leaner, take in less carbs, and decrease the risk of the GI Monster visit (not as bad on bikes as running though).

Rock on
Mike T Nelson PhD(c)
Extreme Human Performance

dr. m.c. said...

why do a time trial? not everyone does time trials; lots of folks do mixes of hard rides and not so hard rides. if for two hour+ hard rides i'm doing better with less, that's a happy thing.

how do we know this higher protein reduced carb drink isn't enhancing metabolic flexibility. when you say "we already do this" who what when where?

dr. m.c. said...

Klashu, thanks for writing, but i can't go there with you on "drink milk"

too many folks have issues with ingesting or using milk to recommend it as a panacea; it's also higher cal; it's also not an optimal mix of electrolytes which most of us also want in real world ride situations when also wanting to stay hydrated in the heat. it's also animal based so not everyone's up for it. and it's not clear that it's "better"


Hanley Tucks said...

As I said, you can get more complicated if people have health or dietary issues.

"Usually, ordinary food and drink is better than a more expensive version in a glossy packet."

Lots of people get scientific about things. Other people just eat good food and get their bodies moving. Speaking of optimal nutrition for endurance, Cliff Young comes to mind. Sydney-Melbourne run, he won it at the first attempt at age 61, defeating professional athletes a third his age - and beat the record by two days. A couple of years later he broke the 24hr run record with almost 236km. When he was 77, he'd slowed down a bit and only managed 147km in 24hr. He was a vegetarian, by the way, and so far as anyone knows, never encountered protein powder, Gatorade or anything like that.

He just ate good food, drank water, and kept moving, however slowly. I'm sure there are many studies that say it was impossible or a bad idea. The science is interesting stuff, but let's not lose sight of the actual real-world performances we see.

Book knowledge, experience. The most competent people have both, and combine them in practice. It's tempting to think only one matters, but foolish.

Generally-speaking, ordinary food and drink is better for you than stuff from a glossy packet - whether it's a glossy packet of junk, or a glossy packet of supplements. If supplements were that brilliant, then penniless Kenyans and Nigerians would not be defeating rich Westerners in distance and short runs both.

Years of hard work plus good food.


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