I’m training for a 100-mile mountain bike race and trying to dial in my fueling strategy. I’ve read a lot about the 90g/hour carbohydrate target and the idea that “you can’t eat more than you’re burning.” But does that recommendation make sense for those of us with lower FTPs?
My FTP is 216W, so I’m not burning as many calories per hour as some of you. I’ve started adding longer rides, and my last one was 6 hours, with TrainerRoad estimating around 2,500 calories burned.
For simplicity, using Gu gels as an example (22g carbs/100 calories), hitting the 90g/hour carb goal would require ~25 gels over 6 hours, adding up to 2,500 calories—which matches my estimated burn. But in reality, I mix in solid foods, which likely puts me over my calorie expenditure.
The race I’m training for will likely take around 13 hours. Given my FTP and burn rate, should I be focusing more on fueling by calories rather than strictly hitting the 90g/hr carb target?
I think this depends on how close to/over threshold you’re riding those 6 hours. Easy/moderate rides for 6 hours just don’t need 90g per hour plus other food imo. The other answer to this question is, are you gaining weight? That will tell you if you’re over consuming calories in short order.
I think aiming for around 40-60% of your estimated “calorie burn” is the right approach. If more intense or longer duration, aim on the high side. With a 216w FTP, assuming you’re doing like 120-140w for long rides, and burn 400-500 calories an hour, 40-70 grams of carbs an hour. You will absolutely want to experiment for yourself though and see what works and feels best. For reference, my FTP is around 50% higher and I haven’t found any benefit above 80-100 grams an hour in any situation.
I have a similar FTP and I went with what „feels best“ after a lot of trail and error. I don‘t overeat and try to eat as healthy as possible. Means I probably don‘t get enough carbohydrates and I have to fuel even with shorter rides (1.5-2 hours). I feel best with around 60g/hour (a bit more on harder efforts). Recovery is good too.
I had to find that out. I tried 90g/hour and it often just didn‘t feel right (sometimes felt great though). With 30g/hour recovery suffered.
I listened to a Tim Podlogar podcast where he recomended starting off with less CHO in the first hour or so and gradually increasing the amount per hour as the event goes on. This approach minimises the blunting of fat burning by eating too much CHO initially and then takes into account that you need plenty of blood glucose as time goes on as the body starts to restrict the release of muscle glycogen as it get more and more depleted.
You’re correct, this will be below threshold. I’m guessing around 500 calories/hour.
Thanks for the replies. Sometimes all of this information I’m reading and hearing in podcasts is geared to faster and younger athletes (currently 51) and it’s hard to differentiate.
You may consider experimenting with drink mixes. As you mentioned, 25 gels is a lot, purely from a dynamic perspective of storing, opening while riding, etc. several others gave good input regarding your question, but that specific thing stuck out to me. It’s much easier to drink calories such as flow formula or tail wind. Just make sure to dial it in beforehand, not race day!
The 25 gels was only to keep calculations simple, seemed to be most carbs-to-calories ratio and highlight I’m probably overeating from a calorie perspective.
In reality, I’m playing with a mix of drink, rice cakes, maple syrup and gels and plan to try other solid food besides race cakes.
To put things into perspective, at an average power of 140 W (around 65 % of your current FTP, an easy endurance ride), you’d expend around 500 kJ per hour at the pedals, which corresponds to about 500 kCal per hour in total energy expenditure if you assume an efficiency of around 20–25 %.
100 g of carbs have around 400 kCal of energy. So even fueling this mellow endurance ride at 100 g/h, you wouldn’t break even.
Independently of your FTP, you might want to adapt the amount you take in. For intense sessions, I take in 110–120 g/h, for endurance sessions 80–90 g/h.
No, it is hard work to fuel with 90 g/h for 13 hours straight. Get in as many calories as you can and don’t worry about weight gain or so. You won’t gain any weight. (Keep in mind that your weight might fluctuate a lot, depending on water retention before the race and sweat rate.)
Check out nutrition plans for Ironman and other ultra endurance events. I prefer to take liquid calories as I also need a lot of fluids, so drinking/eating something every 20-30mins. It takes practice and there is some variety between people, but I think I’m around average on nutrition but high side on fluids, needing 750-1000ml per hour.
Although I agree with most of what you wrote I have a problem with last sentence. I would agree if you would be restricted to the day of the training. If you plan to ride hard and or long in the days following there is a benefit from higher intake still.
Where do you get that number from? Why is that the right approach?
I don’t think this is in line with what we know now about nutrition. 40–70 g/h is too low. And the issue with the “feels best” approach is that it ignores carb intake is something you can train.
Individuals definitely react differently and e. g. gut distress and palate fatigue are real. But some of these factors can be mitigated. I don’t like things that are overly sweet. So I add 30–40 ml of lemon or lime juice to my bottles to add some sourness and tartness, which makes drink mixes more palatable to me.
I paid someone with a degree and certifications that has plenty of experience with both world tour and masters athletes (that have won at the highest level) for a complete nutrition plan for on and off the bike. Do whatever you like though. If you’re winning and have a totally different fueling strategy, I’m glad you found something that works!
Here’s a relevant video that was just posted. Cam Nicholls ate around 700 grams of carbs on a 6 hour road race and thought it was a “disgusting amount”. Roughly 53% intake vs expenditure while on the bike. Yes, 900-1000 grams total including the pre-race carbs and breakfast, which we all know fueling off the bike is as important as on the bike, but since this topic is about “while riding”… Chris Miller also posted and said he had 660 grams, which is around 100-110/hr, and burning through roughly 2x as much energy as the OP. Again, if you want to eat more and it works for you, that’s great!
Yes, but my understanding is that this is because athletes are taking in as much as they can, not because they think 53 % is desirable or “the right number”.
AFAIK according to the “classical” literature, carb uptake by the body is limited to 90 g/h (60 g/h glucose and 30 g/h fructose). Tim Podlogar has challenged that consensus in recent works and many athletes are taking in significantly more than that.
My FTP is comparable to yours (320–350 W, depending on training status), and I have been consuming 100–115 g/h for hard workouts and 80 g/h on longer rides or for endurance workouts.
Yeah but you don’t need to replace 400kcal worth of carbs if you ride at Zone 2 pace as you are not burning that amount in carbs… Your burning closer to 250kcal in carbs. Unless you train your gut I don’t see much reason to go over 60g/hr for wattages and intensities that low.
People are variably efficient, but let’s just say 125 watts for an hour is ~400kcal or ~100g of carbs. (Plus the fire doesn’t just shut off the second you stop pedaling.) I’d say experiment during training however you want, but if I’m racing, I’m taking in 90g an hour min. Sometimes more. I don’t have a “high” FTP either.
The way I feel during long rides (races especially) significantly changed for the better when I started taking in 90g.
That’s false for most people. Have a look at the example I provided above: at 140 W (which is easy Z2 for OP and easily achievable for the majority of TR athletes) you burn 500 kCal per hour, not 250 kCal/h. You’d have to lower your output to 70 W average, which is low on any scale.
Given that you are burning 500+ kCal/h even on Z2 rides (again, provided you are averaging 140 W or more), then you need to replenish this energy at some point. There are multiple reasons why you would want the energy deficit to be as small as possible in many circumstances. Reasons include having a more stable diet off the bike and a lowered RPE.
No you are burning 500kcal but only half of that comes from your glycocen stores the rest is fat. You don’t need to replace the fat part with carbs during the ride. Replace that with healthy foods after the bike and during the day.
