IM nutrition help

Hello all,

I did my first IM in Texas last April. Although I met my objective (sub 13), I’m still well… disappointed in my run performance. I did about 1:30 swim, 6:00 bike but the run was over 5 hours which I didn’t expect. As soon as I got off the bike I had BAD stomach cramp. As in 10.5 minutes mile is extremely painful. If I drink I feel already full, if I eat (gel etc.) I feel like puking. More about me:
First time IM
Only marathon time is December 2016 and was 4:22
Nutrition on the bike was infinit go far, 1 serving per hour. The only other thing was a stinger waffle, 30 minutes before I got off the bike
When I did long brick workout all of them were painful
I usually train on an empty stomach. I wake up drink water and start training.
A friend who did multiple IM suggested I use more solid nutrition(PB&J sandwich, pretzel, etc.). Is that the way to go?
Thanks for your help!
Also at the end of my IM I was very dehydrated even if I drank water a lot (as in peeing and only a handful of very dark yellow drops would come out)

Hey there Charlie!

I’ll leave the recommendations up to the triathletes in this forum as I haven’t personally done an Ironman.

That said, did you get a chance to listen to the four latest podcasts we put up while Jonathan, Nate, and Chad were in Kona for the IM World Champs? They interviewed 4 different athletes and talked all things triathlon. If not, here is a list of them including what they talked about regarding nutrition.

I hope this helps!


hi @Charlie_1980 sorry to hear about your troubles. Lets see if we can get this fixed… I would agree w/ @Ian check out the recent episodes if you have time. Overall, there are some general rules of thumb but no right or wrong answers as everyones body has different needs. There are certainly things you can do to prepare your body to handle race like conditions better but more on that shortly. It sounds as if you have two separate issues , nutrition and hydration. From a nutritional standpoint here are some basics. The limiting factor as far as nutrition goes is absorption. In general, for endurance events such as Ironman or half ironman (anything longer than 3hrs) a good guideline would be to take between 30-60grams of carbs per hour. There are 4cals per gram of carbohydrate so this is equivalent to 120-240calories per hour. This may sound counterintuitive but athletes who are out on the course longer usually require less cals per hour. Professional athletes who are cranking out tons of power need more calories and often times push the absorption limits to get their requirements. Tread with caution however as the more calories you take in the more prone you may be to GI distress. Infinite and other nutritional companies utilize various sources for carbohydrates (Sucrose, glucose, maltodextrin) or usually a combination of them all for different absorption rates. It sounds as if you were taking 1 serving of infinite per hour which is usually around 230calories. You may need to dial that back to the lower limit or around half that serving per hour. If that doesn’t work, you may need to try different nutritional products as they may agree with you more. It is also important to train your gut just like you train your heart, legs and lungs. I usually try to do my long aerobic rides in the months leading up to my races on the bare minimum of calories to become more fat adaptive. In the last 4-8 weeks before an Ironman, I recommend doing some ‘‘long days’’ in which you perform a metric ironman and practice your race day nutrition. Wake up like you would before an Ironman 3-4 hours before, take in some good calories 200-350cals around 3hrs prior to race start, swim 3.8 yards, take an hour (or 2 at most) break and ride at least 112km, take another hour break and run at least 26k. From a physiologic standpoint this is less taxing on your body and does not require much rest outside of any other long training day. It can be mentally taxing but will help prepare you for race day. Of course there is nothing quite as taxing as the race itself so it is still hard to be sure how your body will react on race day. Some people actually like to schedule half ironmans anywhere from 2-8 weeks outside of their full. I would say if you tried all of this and are still having problems you may want to dabble with the whole foods such as you suggested. Heck, the original ironman participants had bananas taped to their top tubes!! It isn’t impossible to do especially with being able to pick up a special needs bag.
From a hydration standpoint, it definitely sounds like you need to be taking in more fluids. The reason is two fold. One, it can stress your cardiovascular system and even begin to raise your core body temp. Two, the more fluid you consume it will actually aid in digestion!!! I suggest weighing yourself before and after long rides and runs (evening swimming) while accounting for your fluid intake to get your personalized sweat rate. A good starting point may be around 1L per hour. This will depend on the heat and humidity as well as the different paces you may be riding at so their is some wiggle room. A good goal would be to urinate at least twice on the bike (somewhere just over half the bike ride and another towards the end) as well as once on the run. You may also need to step up your pre hydration as well. This is something I touched on in the podcast so check it out when you get a chance. Hope this helps! Happy training


‘A metric ironman’…I have never heard of this but think I will definitely add it to my training, something just a little but longer than the half distance that will challenge the body and test the nutrition.