Both vanilla and chocolate gu contain caffeine. Power gel strawbanana contains none.

Caffeine is known to increase gastric acid production in the stomach:
https://www.ncbi.nlm.nih.gov/...articles/PMC5544304/

I have a friend who is a big coffee drinker and always complained about severe stomach cramps during the run. He tried all different foods and hydration etc.

It wasn't until he stopped using coffee on race morning and caffeine gels on race day that his cramps went away.

Sounds to me like some kind of bacteria from the water. That kind of GI distress is what one would expect from bacteria overwhelming the GI system.

I figure that I need 4-6 calories/kg/hour on the bike. (70 kg male, 280-420 calories per hour). I usually go on the lower end of this scale. I am a 5:30-6:00 IM cyclist, so 5.5 x 280=1.540 calories, 5.5 x 420=2,310.

I plan to get all of those calories from liquid nutrition, ie my water bottles. I mix four water bottles with 500 calories per bottle. Two on the bike, two to be picked up at bike special needs. 2,000 liquid calories available to me, that I have trained with in preparation for the race. This is my nutrition for the bike. I supplement with water at aid stations, how much water depends on how hot it is.

If I have done it right, I am well hydrated and fueled coming off the bike and need very little for the run. I'm not super fast but I have several 3:30 marathons off the bike where the only thing I have consumed for the run is coke and water (I shoot for 1-2 calories/kg/hour while running). Zero electrolyte supplementation on the run. Coke is a wonder drug during the IM run.

This is what worked for me. I used to have GI issues while racing but this plan has solved all of that and I have multiple finishes where I have not run out of energy and have finished feeling good. I scale it down for HIM racing.... basically just half the amount that I use for IM.

Sounds like I’m not eating enough. Although, I took one gel every 30 min on the bike or run during training. In my prior Ironman races, I took a gel every 20 min, but I can tell my metabolism isn’t the same as it once was, so I cut it back.

What liquid nutrition do you use?

Point taken.

However, power at website shows caffeine in powergel. Look at the pic of the gel.
https://www.powerbar.ca/...l/strawberry-banana/

Huh. That picture above is the one that I Google when I made the comparison.

I'd still submit the most likely cause of stomach distress be the chemical that causes increased acid production in the stomach, but I realize caffeine is kind of near religious significance for many. It might just be related to you going a bit harder than normal combined with the caffeine. I can't imagine you having severe pains 40 miles into the bike from lack of calories unless you weren't eating anything. I'd start with eliminating the drug from your nutrition first, but again I realize this likely has a lot of lifestyle implications to it also.

I went into Ironman Barcelona feeling good. During the race, the swim felt good and I was running quicker than my expected pace on the bike. An hour into the bike, I decided to back down the pace and play it safe even though as felt good. All was good.

At mile 40 or so, I started feeling stabbing pain in my stomach. I first ignored it and figured it would go away. By mile 80, it didn’t go away and was getting worse. I took in as much nutrition as I could and drank a bottle of water. I knew the inevitable, but told myself I would finish the bike and see how a I felt. The pain was worse and I literally was in tears as I rode. It was a sad sight. A grown man weeping as I rode. I finished the bike, making the cutoff…. But, ai chose to turn in my chip and take a DNF. I went to the hotel and didn’t eat anything that night and the next day slowly took in food until I felt “normal”.

During the swim, I obviously didn’t take in nutrition. On the bike, I drank water every 20 min and a gel every 30 min. The sports drink on course didn’t taste great and at first, I thought that was causing the stomach pain. Now, I don’t think so. When the pain began, I started missing times I was suppose to take in gel and sometimes water, but I tried to continue water as much as I could. I never bonked or felt like I was losing power or energy. Just stomach pain.

I always had a stomach like a garbage disposal and I could eat anything and I never had GI issues. Maybe that now changed.

Prior events, I used Powergel strawberry banana and it worked just fine for me. This year, I couldn’t find it …. Maybe it is unavailable now. I used GU instead and settled on vanilla and chocolate. I’m not sure if it was the GU nutrition not absorbing, I don’t know.

Help! Give me your thoughts and nutrition info as well

Sounds like you are unaware of what energy drinks was given out on the bike, and hence, you have not trained with this type of energy.

In general: NEVER try anything new on race day. That goes for nutrition also.

The pain was worse and I literally was in tears as I rode.

I’ll leave the advice giving part to experienced 140.6 finishers - in fact any 140.6 finishers - but you skipped some important facts. Like: how much water did you drink? “3 times an hour” could be 150 ml or 750 ml an hour. How much of the sports drink did you drink? What was the weather like? What position were you riding in?

With this description of pain, and assuming it was the physical pain (not the mental) that made you cry, I would also look elsewhere than nutrition alone.

Did you swallow a lot of air or water during the swim?

Did you try to take a potty-break?

Problems that probably contributed, if I'm understanding correctly:

1. Pace on bike too fast too early.
2. Insufficient water
3. Substantially more carbs & sodium per hour than typically used in training. It sounds like you reduced your gel intake rate from 1 per 20 min to 1 per 30 min in training. Then in racing, added carb solution from aid stations.

Those three things taken together probably gives you your answer.

I doubt that caffeine played a significant role in this. Caffeine gets a bad rap because it's so potently 'sensed' by the user, and so it's assumed to be pretty abrasive to the gut or other systems. It's not. It's far more likely that other things besides caffeine contribute to GI distress for most people. Even when it's narrowed down scientifically (through testing and process of elimination) that coffee is the primary irritant for someone, it's almost never the caffeine that's the culprit, but the acid, or caffeine-induced anorexia (caffeine blunts hunger) followed by dehydration followed by rapid over-consumption during a sugar crash, or other chemicals in the coffee, or hyponatremia contributed to by way of non-sodium fluid consumption, etc etc etc.

Not sure if I swallowed air or water, but I was feeling bloated and gassy and tried to use the bathroom, but I wasn’t pissing like I was mega hydrated. Maybe a mix of mental and physical, but the physical pain was a 9/10 when the stabbing pain would occur. This was my first DNF, so I’m certain mentally it played a role.

I'm not the fastest but I've done that race before. I doubt you overcooked the bike because it's one of the fastest courses anyhow, with good drafting - legal or not.

I'm curious: what did you eat for breakfast before the race, and how much? This is where you can get tripped up on a destination race because it might be hard to find exactly what you normally eat. Your dinner the night before might have got you also.

Sorry about the bad luck - I really like that venue.

P.S. know the on-course options well before you race. IM seems to be offering Maurten gels at races lately. I think they're disgusting.