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John Cristiano

I have gone through 2 occasions of stomach shutdown when using a carb-protein drink during an Ironman. I had very good results with the product during training (with bricks up to 6.5 hours in length), but at about the 8.5 hour mark the shutdown issues began.
Are there any recommendations about the amount of calories/carbs per hour as I start to look for a new nutrition strategy going forward? Also, do you see any possible benefit to using a carb-protein product for the first portion of a race prior to switching to something simpler to digest (I'm thinking around mile 60 on the bike where special needs typically is staged)?




I understand the point that the calories were higher in certain trials, but were the quantities of fluid used the same? It could make a difference over long distance if you can more bang for your fluid oz?

Joe Friel

Colm--If I recall right, every study had the subjects use the same amount of fluid for each trial. But feel free to check for yourself with the abstracts links provided under References.

Joe Friel

John Cristiano - The standard answer is 240 cal/hour. But that will vary with body size, exercise intensity, and personal experience.

Rebecca Frederick

One other thing that is missing from most of these studies is any potential gender differences - is there good recent evidence that it works the same or differently in women?

Jay Austin

Thanks for taking the time to write so much. Everyone is fantastically busy, and given your schedule I can't imagine how you find the time to squeeze out even one blog post per month...

Anyway, my question is a follow up to the "240 calories per hour" standard.

I recently listened to a very interesting podcast where Sunny Blende was interviewed by www.Ultrarunnerpodcast.com

She noted that fructose and sugars (other than sucrose) get processed by the liver before they become available for the muscles to do work. She called this a separate pathway and allowed for a slight increase in calorie per hour standard.

Reading your post here made me wonder if there isn't another route for protein too. And if so, is it different enough that you can slightly increase your caloric intake per hour by adding protein to your 240/hr?
Thanks again.

Joe Friel

Jay Austin--I know of no 'separate pathway' for protein. Sugar is closely monitored and processed by the body as it is viewed almost as a toxic substance. So the body does unique things with it (e.g., converted to glycogen, glucose or fat very quickly after processing) that it doesn't do with fat or protein. Again, the standard 240 cal does not take into account body size etc.

Joe Friel

Rebecca--Yes, if you look down the list of refs you'll find one that focused on women. A couple of the others also had male and female subjects. These found no differences if my memory serves me right. But can check for yourself also.


Great post. I'm 4:1 carb:protein user, and it works for me -- it keeps me from getting that queasy-depleted feeling after 5-6 hours of just taking in sugar. I'd never considered that the effect might be from the added calories. Very interesting.

It would seem that the presence of the protein would slow the rate of absorption of the sugars, i.e., lower the glycemic index of the drink. This would help some people avoid problems with blood sugar spiking in response to a pure-carb intake, then crashing as insulin surges in response to the spike in blood sugar.


Joe - What about the consumption of BCAAs vs other forms of protein (whey or casein)? Many drinks are starting to add protein in the form of these BCAAs and they claim to be absorbed easily and not cause and stomach shutdowns. Also, I know this article is about Carbs and Protein but what about Fats from Multi Chain Triglycerides (MCTs)? My understanding is that these also have some benefits for Endurance athletes and I personally have not had any stomach issues when consuming them.

Tad Fullerton

Great post.

I've been reading two books by John Ivy and Robert Portman, Nutrient Timing and The Performance Zone, and these advocate protein and carbo, seem to be well referenced and may be of interest to you. Nothing in these books go out anything like 8 hours though. It seems like protein in the post exercise drink is benificial.


Chris Livingstone

Joe--Can you summarize recommendations for a sports drink for use during exercise? Is there a commercial product you favour, or a recipe for a homemade one?





I have been interested in this post ever since you mentioned it. Thanks for sharing your knowledge, opinions and experience with us.

You mentioned "sports media endurance" in the earlier part of your post. Then in the latter part of your post you pose the rhetorical question of whether or not to use a carb-protein drink mix and also mention that there is no benefit/downside for exercise sessions less than an hour. This raises a big question for me, how long were the exercise sessions of the studies? How long was the time trial? In my honest little opinion I wouldn't consider 60 minutes and maybe not even 3 hours an "endurance" session. When I think of endurance, I think of a marathon, or a cycling century that takes 5 to 6 hours to complete.

I just completed my first LOTOJA (which I owe this success in great part to incorporating as much as your Racing Bible knowledge into my training as I could). In the past year I have been learning to train and complete endurance events with nothing more than water, sports drink mix, sports gels and an electrolyte supplement. The sports drink uses a mix of complex carbohydrates, maltodextrin and just a bit of sugar (about 1/6 to 1/8 of total carbs), soy protein and fat.

It took me just over 11 1/2 hours to complete the 206 mile ride while consuming no solid food; just the above described energy sources. I personally swear by this program. At the end of the 206 miles I felt like I could have kept riding until the sun went down, I felt great. The legs were still firing and at that time I had no stomach distress. Introducing solid foods afterwords was a bit interesting but not a big problem. I would argue that there is a benefit to carb-protein-fat drinks; I guess I am not sure how to compare them to Carb-protein drinks.

But my main point is, I would not use a carb-protein drink on any exercise session lasting less than 3 hours; sub-60 minute session would be unheard of for me. It seems to me like the protein would not be necessary until MAYBE after two hours, but most likely 3 hours or more, so why are there studies for shorter sessions, but not long endurance sessions of several hours, like 6, 8, or 10? That is what I would like to see some data on.



Joe Friel

David--Most of the studies used time to exhaustion at a set percentage of, for example, VO2max following a long warm up of usually several hours. If interested follow the links for each study for more details.

Joe Friel

Chris L--It's pretty much an individual call based on taste, cost, availability, etc. For my 3h and longer rides I use Coco-Cola.

Joe Friel

Henry--Yes, there are studies on these nutrients in sports drinks also. I wrote about them in my Training Bibles.

Jonny Creatine

I've never seen advice to take protein during exercise, only before and after. I can't see how it could fuel athletic performance effectively so quickly?

bmi converter

Hi Joe,
Can you let me know what brand or what is the name of the Carbohydrate-Protein drink that you have tried? Maybe you can recommend one... don't worry, I will not blame you if I got burn out..

Joe Friel

bmi--I don't use CHO-PRO drinks at all.

Iron Mineral

Hi Joe,
What are health benefit of protein supplement?

Joe Friel

Iron--Supplements are best avoided. Eat real food. If for some weird reason you can't then use a supplement--sparingly.

Paul Lundgren

Based on my personal observations the benefit of a carb/protein drink is not worth the risk of stomach issues in events under x-hours. My concern is with events over the norm in time. I'm struggling with 12 to 50 hour events and finding the optimum solution that works with both digestion and physical requirements. The question I have is at what point does protein become more of a concern and do you recommend a ratio of carb/protein in stages of time?
Thank you,

Joe Friel

Paul--Personally, I don't think protein is every necessary during a ride. That said, if you're going to use it very, very long rides would be the time--as in RAAM and most long brevets.

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