Yes, but I'd be pushing close to 6mg/kg caffeine to will myself through it. And it would probably feel utterly awful.

If for some reason I was actually limited to such fueling, I'd probably consider a keto diet or at least substantial training without any fueling at all.

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I've had an interesting battle with distance in the past, I used to always bonk massively hard, so I REALLY focused on getting better adapted to fat oxidation during exercise.

Now I find I do half irons with basically nothing on me. I'll be lucky to finish one bottle on the bike of whatever-ade, and maybe a gel on the run.

My nutrition strategy when I qualified for boston was 2 gels.

Now I'm sort of going the other direction, I know that I'm able to oxidize fat pretty well, but I am slowly training myself to eat and drink more and more on the bike, as to have stronger workouts, and not limit myself when I race.

It's taking time to get used to, but my upper end workouts are getting stronger, and my FTP just tested the highest it's ever been.

Be interesting when racing comes back around here to see if I've succeeded in getting myself better carb adapted :p

Sure, could finish a five hour race with no nutrition. Just that with nutrition it might be a three hour race...

I did several HIMs, under 5h, under 300 calories. (I was in my 50s)

I am diabetic and at that time not on insulin. Until I found Generation UCAN I didn't have much of a choice

My diet, due to my condition, lead to me to be more of a fat burner.

You know that your stomach issues are because of lactic acid right?
Going too hard for too long means you're body can't clear it, it builds up and makes you want to puke.


I used to be able to race like that when I was younger. I did half ironmans on whatever I ate for breakfast, a single gel on the bike and a few cups of coke on the run.

For gravel racing I can usually get in 200-300 calories an hour. One bar or shot blocks per hour with water.

I had acid issues with high intensity races until I replaced gels and drinks containing citric acid

Stress/excitement increases peptic acid in the stomach(bile is bright green/yellow throw up) so it doesn't make sense to stop eating the food that can mop it up. Eating antacids is actually supposed to increase bile production

Calories: yes, but as others said it would greatly impact your intensity or you'll bonk. You'll run out of glycogen way before 5 hours so you depend on fat burning (which you can't do at high intensity). but you can certainly do it if you just cruise along at low intensity.
Water: 40 oz in 5 hours is very low end and I'll be surprised if you are not totally dehydrated by the end of it. I think this is a bigger issue than calories, since even at low intensity you are losing water

You can do a race of pretty much any length on zero calories if you go slow enough.

If you are giving up on trying to fuel during a race, then I’d focus on optimizing fat burning w lots of fasted workouts and possibly a keto diet.

That said, I know several people who struggled with race day fueling and finally got it figured out. The key for all of them was pushing nutrition hard in their training. It’s an often ignored part of training. If you can’t consistently take in x grams of carbs an hour in training, don’t expect it on race day.

I probably did that in Chattanooga 4 years ago. Both my main bottles ejected at the start with all my nutrition. Plastic bottles wouldn’t stay in, so I had almost no nutrition and very little water on the bike. I ate 2 packs of gels on the run plus a little more water. I was definitely out of gas on the last 3rd of the run. But surprisingly, it was my second best HIM performance.

Definitely not alone. I gave up 4+ hour races a long time ago after going 4 out of 5 races in the med-tent / hospital. Kind of a bummer as I'm getting older and slower so its "the time" to go longer, slower and complete rather than compete.

For a half-iron that takes me around 4 and a half hours my nutrition plan is 2-3x 100 cal gels (plus one before the swim). The amount of water depends on the temperature. I never could figure out why many peoples have massive numbers of gels and such taped to their bikes and in belts and the like. I literally put two in my pocket and take one halfway through the bike and one in the last mile of the bike before running.

All that said, for a 5-hour hard bike ride I will commonly eat 2 clif bars plus have a gel, so more like 600 cals. There’s something about a bike ride over 4 hours that makes me need to fuel.

I think a lot of this is very individual, once you get past the minimum required sugar needed after glycogen stores are depleted.

Zach Bitter frequently runs very quick 100 milers on little or NO added calories

https://ultrarunning.com/...miler-in-us-history/

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

I’m pretty sure I could finish 3, not 4 and definitely not 5. I eat alot when racing

Where in the article does it say Bitter is racing 100 milers on no calories?

He talks extensively about his nutrition, though he doesn't explicitly state what his calorie intake is during races. This is the closest quote I can find:

"Since I began OFM, I have been able to reduce my race day hourly carbohydrate intake by over 200 calories and feel better."


From what he says, while reducing his carb intake by 200 cal/hour, for all we know, he may have increased his fat consumption by 100. Or decreased his carbs from 300 to 100.

He does indicate he still races on some level of carbs:

"carbs are “strategically” brought back (as at a race) they work like never before with minimal to no impact on fat metabolism"


I just can't imagine anyone running 100 miles on zero calories, let alone as quickly as Bitter runs.

My mistake - I got my podcasts episodes mixed up

It was actually Mike McKnight who ran the 100 on zero calories, but was referenced on the Zach Bitter episode the following week

https://blisterreview.com/...les-0-calories-ep-51

https://blisterreview.com/...l-world-record-ep-52

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

On the few longer races Ive done I can tolerate maybe 3 or 4 gels before my stomach says enough. I tend to load up a bit the couple of days prior to a long event then post race I stock up. ;)
Its seems like I'll hit a point during the race where I feel the bonk coming on but then kind of blow through it then Im ok.

With a high of 85 there is no way I could do 5 hours running on 40ozs of water. At 40-50 degrees I could do 4 hour run with no water or nutrition as I've done it in the past, but my body doesn't tolerate hot/humid weather well. A white face crust forms at almost every marathon/ultra.

In bike training I generally plan a minimum 1 bottle for each 1 1/2 hours of ride time -- 40ozs is 2 bottles so 3 hours. Stretching it I could probably ride the 5 hour duration, but not race it.

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Swim - Bike - Run the rest is just clothing changes.

So what did you switch to? I had a painful 1/2IM run due to stomach shutdown and I would like to prevent that in the future.

I replaced gels with vitamin c (ascorbic acid) for gu espresso love flavor which tastes not sweet or sour

I would have one bottle of plain water on the bike to drink from if the Gatorade started giving rot gut

And I replaced some if the calories from Gatorade with acid neutral food like dates or power bar type bars which absorb stomach acid

But it's true that lactic acid levels are related so you can pace on heart rate to keep below anaerobic threshold and plan eating away from hilly efforts on the course

By the end of the race cola is great, I never had an issue from the carbonic acid even when negative splitting but I think that's because the caffeine reduces gastric motility

Train more. You went too hard for your fitness.

When I read you statement about 200-300 calories an hour, it reminded me of when I asked a question of the guy who hit 10,000 miles of riding in March. He opened it up for questions so I asked what he eats while riding and he said he hits about 400 calories an hour. I snorted loudly and thought, "Well, there you go. If I could eat 400 calories an hour, I'd probably ride more, too." Just the thought of 200 calories an hour makes me nauseous during exercise.

If you typically train fasted, it's not surprising that you would struggle with race day nutrition. Think of your digestive system the same way you think of your aerobic engine or muscular endurance. For long endurance events, it can be just as important and must be trained to perform during a race.

Yes, the cost is a big factor if you are trying to replicate race day nutrition. Popping ~$1 gels (or whatever) every 20 minutes of every training ride gets expensive in a hurry. The way I compromise - I only do serious nutrition training on my long saturday rides. Very few people can just go out in a hard race and force down 90g of carbs per hour without having trained their body to do it. The old advice "don't try anything new on race day" really applies here. Digestive problems can end a day early, much more so than trying a new piece of equipment.

Also, you might revisit your "preferred" nutrition and look for something cheaper. You shouldn't be married to Hammer products since they obviously aren't working for you anyway. You'd be better off with a "lower quality" option that you can consume consistently during training rather than trying to use something for racing that you can only use on special occasions. Honey in a squeeze bottle is pretty darn cheap and can be effective.

I've generally done what you describe using my long rides/workouts to experiment with nutrition. I've tried the high-tech stuff, Gatorade, pretzels, bagels, gummi bears (my favorite, but a little too sweet) and nothing has really stood out. I'm most comfortable with Hammer products, but can't say they are the be-all and end-all for me. I'm willing to concede that I may gain a measure of stomach tolerance by pushing race-day nutrition for every day training, but I'm not overly hopeful. Today, I jumped in and tried to see what would happen in my sweet spot workout where I hold around 80 percent FTP for a minimum of two hours. I set my timer, drank about 4 oz every 15 minutes (so about 25 calories) and made it through the workout fine (about a 2:45 ride). The reason that I'm not overly hopeful is that I rarely have any issues until I get well past three hours. Since I'm old and can't do that often (once, maybe twice a week if I cut down my running) then really I'm only doing it on my Saturday long rides.
I'm going to try this for a bit and see what happens, but like I said, I'm not overly hopeful; this is not my first rodeo and I don't really expect any epiphanies.