Fueling Zone 2 Workouts

Legit, I am actually asking for a friend!

Any advice on fueling long zone 2 workouts? 2-3 hours. I get that carbs are paramount for higher zone works, but zone 2 seems to be a weird zone to properly fuel.

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60g/hr and go from there. other things to consider:

  • workout day before
  • workout tomorrow
  • how fit you are (2-3hrs proper zone 2 would probably fry a newbie, for example)

edit: i train 10-15 hours a week and take the approach that overfuelling is better than under. A 3 hour endurance ride for me personally is normally around 2000kcal.


Definitely fuel the work. In the words of @ambermalika , don’t diet on the bike. Even with Z2 work it’s important and will have you comeing back stronger for subsequent workouts. It’s also a great opportunity to train the gut and experiment with different foods/drinks etc.


I remember reading or hearing something about eating carbs during z2 rides changes your body from using mostly fat to carbs. Is this something to consider as well?

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a lot to unpack with that but in summary a 3 hour endurance/z2 ride fasted or with the intention of riding low on carbs would be very taxing and put me in a deficit for tomorrows workout.

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Very good point. Short duration, no big deal. Longer duration, it pays to be fueled during and after the effort.

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my 2-3 hour zone2 rides are 170-200W, for 2 hours at 190W that is 1360kJ or roughly 1360 kcals.

I’ve always targeted on-ride replacement of 30-50% of calories burned, which would take eating about 400-700 kcals total on the 2 hour ride. Which I usually do as 2 Cliff bars (250 calories each), or 2 bananas while leaving and one Cliff bar on the bike.

And then after the ride eat real food within an hour. That works really really really well for me while riding 8-12 hours/week.

This summer I tried 400-500 calories per hour with 100-120g bottles of sugar water. No stomach issues with the increased on-ride carb intake. Made no difference to my rides, however it made my bike a sticky mess and I struggled with weight gain despite dialing down calories off the bike. So I went back to the 30-50% replacement rule.

Big exception are hard rides over 2 hours. Those I’ve always done well fueling at 60-90g/hour.

I think you need to figure out what works for your body and how you burn fat/carbs on those rides. Experiment!!!


No you actually NEED carbs to burn fat. Plus your brain needs carbs.


A rule of thumb I use for all riding is planned average power divided by 3 for hourly rate of carbs.
Example: 180W / 3 = 60g/hr


It’s shifts a little bit but not much. The latest WattsDoc of the empirical cycling podcast is all about this. It’s so minor that the conclusion is to just fuel like you would any ride. Especially since there have been studies that do show a slight improvement in fat vs carb burning, but none that show you get any faster because of it.

Every ride/workout I do I aim for about 90g of carbs an hour. Mostly drink mix but in zone 2 rides als some solid foot.
Only for 1 hour (low) zone 2 ride I use a bit less on the bike because it’s easy to fuel that before and after the ride.


I’m not a Doctor, Scientist, or any form of Expert on this subject but here’s my opinion / hypothesis / thought process on the topic.

The thing that really separates the best endurance athletes from the avg isn’t there ability to utilize more carbs an hour on the bike (although yea they’re better at this too)…it’s they’re ability to utilize more fat for fuel. Nothing wrong with Carbs…I F****** love them, but if you always spike your blood glucose levels with gels and sports drinks on z2 rides I’m speculating you probably don’t need to adapt to burn more fat for fuel (Review first point on why this is important).

I’ve been the guy that always fueled for every ride, and to be honest I never got that much better. Of course I saw improvements but at least it’s never felt like I raised my base level significantly or to a degree that I would have hoped. I’m going the other route now, no fueling for z2 rides…I’ll just eat my normal meals, use my onboard muscle glycogen and fat, and If I ride long enough to start to feel depleted I’ll count that as a win and stop for a proper meal before starting off again.

Of course this is just my opinion and I can’t back it up with any proof…it’s just what my N=1 experiences are.


I think this is really bad advice and not consistent with the best available science we have. World tour pros are not fueling with less carbs, they are taking in more than they used to.

Why is it a weird zone? Even if you fuel to the max, if your FTP is 200+ W, you will never be able to replenish the fuel you burn.

Personally, I fuel outdoor Z2 rides with about 80 g/h and indoor Z2 rides with about 80–100 g/h. The difference I feel is due to less efficient cooling (meaning my body has to expend more calories to cool itself, e. g. I also drink about twice as much indoors as outdoors).

If you are a lighter rider (say, 55 kg) and a lower FTP), I’d just scale down that number to e. g. 60 g/h.


I didn’t say eat less carbs. I’m just choosing to forgo the simple sugars on the bike during an easy ride and refuel later with more complex carbs.


You do you. But like I said, that’s not where the science is nor what the pros are doing.


Agree to disagree I suppose. Of course if you can back up those claims with an actual scientific study that shows 80g of carbs an hour on a 2-3 hr z2 ride is vastly superior than eating regular meals then I’d be happy to admit you were right.


The pros zone 2 isn’t 170-200W, and is likely longer than 2-3 hours.

And look at that!!! TR next science of getting faster is this exact topic. What are the odds


I don’t fuel my Z2 rides of 2-3 hours. I find I simply don’t have to. I don’t fade and I don’t feel hungry during the ride. I eat normally and everything is good. I’ve been getting faster off the back of it.

I’m wondering if those who stuff themselves full of sugar during Z2 are doing so much high intensity that their carbohydrate stores are getting burnt through so quickly that they can’t even last 2-3 hours without eating.

Plus I wouldn’t call it fasted riding, just not eating during actual ride. I’ll have had breakfast or lunch before the ride.


I wonder what those who don’t fuel for longer Z2 rides (2+ hours) think the downsides are to fueling during the rides? For me it’s been nothing but positives. Feel fresher on the bike. Less drained the hours after the ride and beter the day(s) after the ride.


This is the crux of it for me, I train early AM, so will not have eaten for over 10 hours. If I do a 2-3hr Z2 session (which could be anything from .65-.77 IF and 1500-2000+Kcal) I would feel pretty wasted with no food. I understand if you have eaten several meals prior to the workout that it would be less impactful, personally I would still fuel moderately even in that scenario as well, at least 40g/hr or more depending on where in ‘Z2’ it was.