Fueling Zone 2 Workouts

Personally I feel like you’ve got it backwards.

Not fueling your rides is fine, fueling your rides is fine.

Noone is saying you can’t do great rides on just water, I think you’re seeing people excited about the performance they are seeing from riding with additional fuel.

This stuff is all cyclical. We were studying the benefits of fueling back in ~2007. Home made 2:1 mixes and ~90g/hr for performance. That was while fasted training was still very popular.

It’ll come around again in line with this Atria/ISM stuff. Currently though, the evidence is clear. You can go faster for longer by fueling properly. You can train not maximising fueling every ride, it just takes more effort to replenish stores off the bike.

For me personally, if I don’t fuel on the bike, like I used to not for all my ~6-7hr IM training rides, I’d have to stuff my face after. I don’t have time for that these days as I ride up until I can hop off and pick up the kids. Fueling on the bike means all I need is a protein shake and maybe something small to eat on the walk there.


Lately I’ve been mostly fueling them with rice cakes (essentially just white rice and a bit of cream cheese crushed into a block). Cheaper and has less wrapping. On a longer (>3 hr) ride I’ll have a clif bar or something for variety.

Not sure what g/hour I’m hitting but I’m not famished or full, so it’s probably fine.

1 Like

As mentioned above, you’re not expecting to ride 112W harder.

Even at 100g/hr, with your 330W FTP you’re still burning through twice the amount you’re fueling at an easy/moderate intensity.

1 Like

He’s unable/unwilling to change his off bike diet and his primary focus is body composition changes - so low fueling on the bike is probably his best option :slight_smile:


Unable or unwilling - it doesn’t make a difference. You aren’t changing your off-bike diet so you must adjust your on-bike diet so you can achieve the weight goals you have targeted.

I’m saying this because its worth noting that your priorities and diet off the bike might be different from others. You are taking a very dogmatic position (as are lots of other people on the other side) in many of your posts (although not all) - so I’m just pointing out the conditions you are operating under


I have held off on posting here as the topic has bounced all over the place. I look at the discussions you have but to me it all comes down to what is your goal. Diet vs bike performance. I see your last comment talks about teeth. Here is my 2cents.

I started to cycle regularly when I was told I need to lose weight. So i dropped 500 calories a day and for the next 15 weeks I dropped 30 pounds. I didnt fuel on the bike till near the end as I did struggle on some rides with no fuel. So I did this work to lose weight…hit goal weight and then went back to my new diet which was no sugar off the bike. Food intake went back to what I previously did. I fueled my rides. Not to the high levels but more like 60g an hour.

So now I was riding regularly, eating my healthy meals each day and consuming carbs on the bike. My weight continued to drop. I had to start eating more.

Seven years later I consciously have to eat more to maintain my weight. My weight is one pound more then what I dropped it to as my goal weight. This is where I have stabilized. I fuel the rides that are more then 90 minutes. I may fuel some of the others but it often is just some electrolytes or how I feel. My own take is I do everything I can to reduce my RPE. If my RPE is low I ride a lot easier…

So my take is fueling my zone 2 workouts only helps me. I fuel to make my rides feel easier. If I dont fuel I am starving after my ride. I am now in my early 60s. My ftp has improved. Improvement roughly 30% higher then when I started riding 7 years ago. No idea if I will keep improving. I dont think what I did to lose weight was smart. Too much too fast. I should of just let my body adjust over time from the diet changes at a slower pace. The cycling accelerated what I was doing. I personally dont see the benefit to not fueling long zone 2 rides other then crash dieting. I did it and wouldnt recommend it.


Everyone has answered this question wrong :grinning:

The answer is, it depends. @empiricalcycling would be well proud of me.

In fact it depends on so many factors you’d have to write a dissertation to answer it.

Many have offered some great guidance. Offering advice on nutrition is like walking through a minefield. There’s always going to be folks that offer extreme advice. These extreme examples are usually best avoided.

Here’s a few things to ponder to help with the “depends”…

  1. Are you trying to change body composition?
  2. How was your fueling through the day prior?
  3. How is your fueling going to be after the session?
  4. What is tomorrows session?
  5. How did your previous fueling go?
  6. Are you trying to increase your fueling tolerance?
  7. How will fueling this ride interact with your weekly fueling periodization?
  8. Is it low/mid/high Z2?
  9. Are you metabolically fit?
  10. Are you very sensitive to lower glycogen levels?

Plus, food choices, gut tolerance, teeth health, environmental concerns…

This is essentially like asking the internet, should I do threshold training?

It depends…


I love it when @TheBandit posts, thank you for being the voice of reason.


I’m still working on being able to read things, cringing, and then not responding. You’re absolutely right - it does depend, and anyone telling you do XXX every time is wrong, including me. I encourage my athletes (and I do this myself) to fuel their work adequately, and that means changing their fueling depending on the ride they’re doing and what they’re eating around that. I completely agree with everyone who’s been saying 100g/hr for every ride is silly. I also think grossly underfueling is silly in basically all circumstances, but again, that’s based on performance and not everyone cares about that.

So stealing @WindWarrior’s statement and adding my caveat, I just tap out with: “Ride longer, fuel the work adequately, win in the kitchen.” What all that means to you? It depends. :slightly_smiling_face:

(Though I do like: “Eat a snack and ride longer.” too. That would be a good t-shirt.)


The takeaway here is just a different view of someone who has done what you said. Dont fuel zone2 rides. I think fueling in some manner for duration and intensity is smart regardless of what your goal is. I would of still lost the weight regardless…it may have taken twice as long but it really wouldnt of mattered as I would of hit that target…I view what I did off the bike being more important then the dieting on the bike.

I know what I did with weight loss I shrug off as it was easy to me. My motivation is likely the main reason I found it easy. Why did I do this? I was 55 and told I had a 20% chance of having a heart attack. Long term I became healthy from a diet change and from cycling. The easy of weight loss did result in me connecting cycling as my medicine.

I understand your point of view. We all react differently to exercise and food.


As a software developer, I can relate so much to this.

The answer is almost always, in most if not all things, it depends…

1 Like


What we are seeing is that some need to fuel themselves with sugar during 2-3 hour Z2 rides else they feel awful / have to cut the ride short, some take snacks and will have them later on if necessary during a 2-3 hour Z2 ride, others can quite happily ride 2-3 hours of Z2 without needing to snack or fuel during the actual ride as long as they are eating okay outside of their ride.

If you were talking 4-5 or 6-7 hours or 8-9 hours of Z2 it’s likely even the latter group would be taking on calories during such outings.


There was/ is also the misconception that “fasted” is just skipping breakfast.

But regarding nutrition, my experience over the last decade of taking an interest is that a lot of the “science” isn’t actually peer reviewed proven science, it’s “evidence” of potential. The nutrition industry has a lot of people trying to sell you something that leap on this evidence before it’s properly backed up (and then develop cult like followings!).

Like Keto, Paleo, and all the “fasting” diet apps around at the moment.

You’re right that dieting is a real minefield of researched, and non-reaearched products and ideas. All to sell a product to a vulnerable group of people searching for an answer.


This applies both to the people selling you products as well as the people selling you fasted riding. There’s a lot of theory out there about fasted riding; it hasn’t held up well in scientific practice.

Lots of coaching interventions might work that science hasn’t shown as effective yet, so YMMV.


Here’s my 2 cents on the subject which I’ve been internally debating for the past 3 months. This is the 2nd time I’ve done the HVSS base program. The first time was the summer during lockdown 2020 when I first discovered TR and just now, my second time.
Some context about me. I’m in my early 50s, 5’7” 140-150 lbs with a high max heart rate. I’m all fast twitch muscle trying to develop my FTP. I started racing Olympic Triathlons in 2014 and didn’t know how to properly train, so everything was high intensity. I was fueling constantly: gels, bars sports drink. I love carbs and ice cream. During the race season, I dropped my weight to a low of 133lbs. My FTP was probably 180. Since 2020, I’m exclusively biking.
Doing HVSS in 2020, I listened to the fuel the ride and don’t diet on the bike. The rides were extremely tough and I was taking gels and sports drink but I managed to get my FTP to 240 at 138 lbs. However, often my rides would have my heart rate at 85%-90% max rate. After that session, it was hard for me to keep that intensity and my FTP dropped and fluctuated between 210-230.
This year, due to surgery on my hand then a broken foot, I didn’t ride from January to late August. Listening to Dr Peter Attia’s interview with Dr San Millàn changed my training. Since the last week of August, I started riding again, almost exclusively Z2 at 73% max HR. I was up to 151 lbs and the first rides were 90 watts for 45 minutes. Increasing my duration to 75 minutes avg, 127 watts, I started the HVSS in October. Every ride this time has been unfuelled and sometimes fasted. I only have 1 bottle of water. Every time my HR goes over 73%, I lower the intensity to maintain the HR. So all my rides are strictly controlled by my HR. Thankfully I use the AI detection and have avoided the ramp test. Z2 @ 73% max HR is “easy”. I’ve completed virtually every ride. I’m not exhausted and wasted after the workouts. I dropped 15lbs and am back to 136-138 lbs. AI has my FTP at 204 and for fun, I did the Full Frontal 4DP Test the other day and my 20 minute block was 207.
So Z2 rides can be done unfuelled but you have to keep the HR below LTV1.
My two goals are to get my FTP up to 4 w/kg and sprint power back which was greater than 20 w/kg @ 5” from the current 14 w/kg. We’ll see how I have to fuel going forward.

1 Like

This. I’ve been reading along and my particular case, for whatever reason has me struggling to meet calorie needs without post workout shakes with carbs AND carbs during the workout, even just a 1hr z2.

I just can’t seem to get through more food during the day. 600g a day of carbs from food, WTF lol.

A normal day is about 300g, I fill the extra through carbs during and after the ride. 86kg rider.

I am new to cycling, TR and endurance sports so fuelling during workouts it’s new to me. 2hr weightlifting sessions never seemed to require it.

Is there a consideration here to preservation of muscle mass too, where not fuelling IF required cause muscle loss?

Also, in my uneducated endurance brain, wouldn’t fuelling z2 speed up recovery and better prepare you for the next session, be it lifting or riding. A single session unfuelled might be ok but if this is recurring and you struggle to meet daily caloric requirements at the same time, won’t long term progress suffer?

I’m So new to all this I’m finding it confusing. Fuel, don’t fuel, fuel intensity but not z2, etc.

What I do know is calories in vs calories out is the number one determinant of ‘weight’ loss. I’ve played with this and lived it for years.

I normally do Z2 workouts up to 3.5hrs with 2 bottles with 60g of sugar each. As additional fuel I bring one or two packages of ginger bread, with 50g of carbs each.

When I started doing these long rides, I would need to eat the ginger bread towards the second hour. Lately I could even do without the gingerbread and was fine with just the two bottles of sugar water.

This morning I had a different experience. Already 50 min into the ride, my legs were burning as if I was doing a threshold interval, but this was just mid Z2. Then when I ate a slice of ginger bread and flushed it with some sugar water, I was totally fine and all felt normal again!

This has never happened before to be out of juice already within an hour. Looking back, the day before I had done a 1.5hr workout, that consisted of 6 all-out 40s intervals with long rests in between. I had probably eaten at maintenance that day, also with plenty of carbs, but probably not enough given what happened this morning. Anyways, the lesson is, even for Z2 rides, always bring carbs!


I don’t know if it was a recent podcast or one of the snippets on YouTube, but I think Jonathan or Chad said that a rider doing 180w for 1 hour burns 400 calories. For me that’s just below zone 2.

That being the case, having one gel (just using gel because it makes the math easier) every 20 minutes will put me behind by 100 calories per hour. If I use a flask and put 4 gels worth in but consume it in 3 shots (133 cal/28g of carb) I’ll be at brake even and roughly 84g of carb per hour.

In EP 9 of the Science of Getting Faster pod cast Dr. Hearris said that their results indicated that eating once every 20 min was the most efficient. (also that another study indicated rice cakes aren’t as good as gels or liquid carbs for fueling but they were pretty good) Are Gels Really That Bad? w/ Dr. Mark Hearris - The Science of Getting Faster Podcast Ep. 9 - #2 by webdev511

So to avoid deficit at 180w you need 400 calories and roughly 80g of carbs. Oh you’re racing? better turn that up to 11 and your best bet is to still do that every 20 minutes.

1 Like

180 W is actually more towards 650 kCal per hour ( multiply wattage by 3.6 to get 650 kCal per hour).