100 gm/hour of carbohydrate?

It sounds like, with training, one can absorb up to 100 gm/hr of carbohydrate if the proportion of glucose to fructose is approximately 2:1. My questions are (1) does that vary with body size/weight (I’m 60kg) and (2) should endurance athletes always attempt to ingest 100 gm/hr carbohydrate during races if they can tolerate it?

My preferred discipline is cross country mountain bike races 2-2.5 hour in duration, on technical single track. I find it hard to ingest that much carb as there simply aren’t times of smooth trail to take the hands off the handle bars. Any tips?

Hey @robertehall1, great question.

Yes, we can absorb quite high amounts of CHO when using multiple transportable sources. I have not seen a specific recommendation based on body weight; just the previously researched absolute intake amounts, but @trevor may have more information on the relative amounts. If we think about some of the marathoners using that level of intake through Maurten and achieving rates of 100g/hour, it’s certainly possible in the case of Kenenisa Bekele, who weighs in at 55kg. But we also have to consider the delivery method in that source of carbs, where the hydrogel essentially bypasses the stomach to reduce GI distress.

If we’re talking about more typical sources of carbohydrate, my feeling is that you need to determine a starting point that is appropriate to what you will be losing during your race and then tune up from there to find an upper limit. It may not be 100g/hour simply because you may not be racing at such a high absolute speed that you are actually burning that many grams of carbohydrate per hour that would require such an intake. So to your second question, I would say that for the most pat, “no,” endurance athletes should not always attempt to ingest 100 g/hour. They should attempt to consume as much as they can within their range of CHO losses.

Technical singletrack can make it quite difficult to fuel, so you have to really be aware of the places you can eat or drink. I’ve run into this before and one thing I’ve learned is that one of the safe places to eat on a technical MTB course is on climbs. The hard part is that we’re usually working hard to get up the climb, and not thinking of our fueling. If you can find opportunities to drink and eat, even in very short segments of a technical course, it will pay off greatly. I raced in a technical stage race a couple years ago and that was the big take-away - use every single piece of “easy” trail to get something in my mouth or take a couple gulps of fluid, even if it was only 5 seconds that I had to toss something in my mouth. Otherwise, we keep riding and eventually we’re 60 minutes behind in our planned intake and have such a large energy deficit that it’s hard to climb out of it.

Can you think of any opportunities in your XC MTB races where you can find chances to fuel, even if only a few seconds at a time?

Coach Ryan

Cool, thanks. Ya I think pre-riding my race course will help plan fueling opportunities.
A follow up question. To achieve 100 gm/hr absorption carbohydrate, does it need to be spread out over the hour?

I have always fueled during training the way I fuel while racing so it’s habit while racing. My philosophy for high stakes/high stress training is you don’t rise to the occasion you fall to your level of preparation (habits).

This is especially important for fueling since its arguably more important to fuel properly racing (and more difficult!) than while training!

I don’t rely on solid food on the MTB. Too risky and too much mental thought/remembering etc involved with bars/gels. But, I also believe in hydration packs which is uncommon so my strategy may not be useful to many.

Anyways, in my hydration pack I put Electrolyte drink (Gatorade or Powerade Zero) for flavor which stimulates me to drink more than water.

My bottles have liquid fuel (Spiz for me, 500 cal per bottle and I burn about 500 cal/hr) and grab a bottle here and there when I can to get fueled (plus additional hydration!)

There is a decent recent book on fueling and the gut in Athletes.

The Athlete’s Gut: The Inside Science of Digestion, Nutrition, and Stomach Distress https://www.amazon.com/dp/194800710X/ref=cm_sw_r_cp_api_glt_fabc_TVs2Fb2BC2B93

@robertehall1, generally I find that a spread out approach is best. That way we can cause as little offense to the gut as possible. So finding that combination of multiple carb sources and consuming small bits regularly, seems to do the trick. I like to think of my approach for fueling during racing like an IV drip as much as possible. Of course MTB racing and other race or course specifics might not allow for that, but in general if I can just maintain a regular tempo with the incoming fuel, I’ve seen good success over the years with athletes and my personal performance.

Coach Ryan

I think Ryan’s feedback is great. I don’t have much to add. Just a couple points:

  1. I haven’t seen too much about body weight and rate of absorption. I think that’s primarily because of the large amount of individual variation in absorption rates. Its quite possible to have someone who weighs 70kg but can’t absorb as much CHO in an hour as someone who weighs 60kg.
  2. I completely agree with Ryan that trying to get 100g per hour is not always the goal. More is not always better. What I’ve really taken from all the research on absorption rates is not the top end of what we can absorb, but the fact that we should consume a mix of glucose and fructose at a little over a 2:1 ratio. After that, you really just need to experiment and see how much you can consume during hard activity without causing any G.I. distress.

Even though they look dorky in a XC setting, when I have a MTB race or training where fueling is important, I use a psuedo bento box. I can get it open and closed without looking. I love figs and chili spiced dried mangos in the box. These contrast enough with my primary liquid fuel that I don’t have any issues. As for the liquid fuel, I have experimented with Beta Fuel and Maurten 320. Both are in the 300+ Cal per serving range. I like Maurten 320 waaay better and going forward I won’t use Beta again. Feel free to put it in a camelback.

@SteveHerman, good call! Regardless of looks, having your fuel accessible is really the key. What is it that you like about the Maurten 320 versus Beta that would keep you going with Maurten? I haven’t used either before, so always curious on experiences with other fuels.
Coach Ryan

@ryan I really like the texture of Maurten. The hydrogel feels kind of slimy and thick on the pallet which sounds gross but for me is much nicer than the gritty texture of Beta Fuel. I’ve never had legitimate GI issues with either drink mix, but with Maurten I forget that I just drank it vs. Beta where I know that I just took a Calorie bomb. I don’t know if that last bit makes sense.

I like Maurten’s too given their ideal glucose/fructose ratio, just don’t like the price. For drink mix, I’ve resorted to a home mix of maltodextrin, fructose, and a pinch of salt. Maltodextrin:Fructose in a 2:1 ratio. Maltodextrin and fructose can be bought in bulk on amazon for dirt cheap. I think it was like $20 for a 5Kg container of maltodextrin.

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I am new here :slight_smile: so a little late to this party. I too recommend a hydration system for my mountain bike athletes. This allows you to drink take in nutrition on most types of terrain which really helps with keeping consistent during the hour.

I really like USWE Sports hydration packs and use them for mtb and moto, super comfy and stable (no I don’t get them for free or a discount, straight from the website).

The other idea as well is to use a top tube-type storage system to hold solid food as recommended earlier. Easy to reach for and right in front of you so you don’t forget.

Had an athlete do the BC bike race and it took a few conversations for that person to use this on their top tube. After one training ride, they were convinced, came in handy for the second-place finish they achieved :).

Nice! I got a USWE pack for xmas and just had a chance to try it out last week on a bike trip. The pack is light and stays snug with the strap system. It will definitely help me get the calories in as I hate taking my hand off the bars and reaching down.

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Another thing that works well for events with a drop zone, is to have two identical packs. Whatever items, tools, nutrition you carry when you start, have a second to leave at the drop. Then when you come to that feed zone, you can change your pack in less than a minute and have everything in the same spot!

I’ve tried maurtens, beta fuel (SiS) and super fuel (skratch). Skratch is by far my favorite as it’s the lightest (doesn’t taste that sweet) I can barely get superfuel down… It’s far too sweet. Maurtens is just weird. None of it’s cheap, but I can get super fuel 20% off at my LBS and then get points for them afterwards by sending in a receipt.

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@robertehall1 @smashsquatch have either of you tried Tailwind? I have had great luck with it with many clients and myself. Everyone is different just wasn’t in your list so wondered?

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I’ve used it for regular training and liked it. Although I’ve never had gastric issues… I’ve also never tried to push the 90g+ range / hr until recently with the above mentioned brands.

I didn’t think you could use it (tailwind) for high calorie rides though due to the lack of fructose (which allows to cross the traditional ~60g carb /hr)? Have any of your clients tried mixing 4 scoops? Was it palatable? Digestible?

@smashsquatch Not quite that high 70-80 yes. Usually used in combination with Born Nutrition liquid gels.

I’ve been working on this because I’m so bad about “dieting on the bike” or just forget to eat when I try to focus on it outside. It’s much easier indoors when you can lay everything out in front of you.

Two things I’ve done to help are to set my Garmin to alert me when I’ve burned 250 cals as reminder to eat and I’ve added plain water back it. Since I forget to eat, I figured drinking it would be the easiest solution, but I was having stomach issues. I went to more solid natural bars like Bonk Breaker or Enduro Bites to go with some SIS gels and do 1 bottle of H20 for every bottle of drink mix. That seems to have helped with the upset stomach issues.

These look interesting. Isotonic but without all the artificial sweeteners SiS puts in thiers. Do they have any online distributors in the US? I’ve never seen them in my LBS

Hi @smashsquatch

I really like their product.

I have done 5-7h rides with just water and their gels.

I haven’t had anyone try them who doesn’t feel the same way (n=12)

Oddly I don’t get too into the different type of sugar. For about 8 years my clients have been competing mostly in mtb stage races, 3-5 hours per day, 5-7 days long.

I find that when an athlete continues to use the same product year after year without complaints there is something there.

These products have been:

Infinit ride with personal mixture


Born products.

Hope this helps.