Here’s an interesting question I got from one of my athletes who just completed a half Ironman triathlon. Her question pertains to nutrition and sustain energy during the race and there are a lot of important points here.

Hi Doc,

I had a pretty good race yesterday, was happy with the early season performance since I haven’t been feeling 100% as you know and I felt a little undertrained on the bike. Anyway, I have a nutrition question for you.

I got up about 4:45 am, had tablespoon of MCT Oil, and then in a bottle I mixed up ketones, creatine 5 grams, 1 1/2 scoops of UCAN and drank that about 5 am.

At about 6:45am I had a croissant and a hard-boiled egg, then started the swim at 7:20.  I was on the bike by 8am, had a Vespa Jr in the first 30 minutes, then another at about 2 hours in. I started the run at 11am, had another Vespa. I never felt hungry but about mile 10 I felt like the wheels started to come off. I had a Gu gel with me so I had that and finished fine, but I feel like I maybe should have either had something more on the bike or done something different so I didn’t get to that point where I felt like I had to eat but still wasn’t really hungry.

Thoughts? Should I have had more to eat on the bike?


There are several issues to address in this scenario. Just to recap this is a female athlete competing in a half Ironman event and is someone who is relatively well fat adapted.

  1. Carbohydrate intake. The prerace nutrition seems pretty adequate for the event at hand. UCAN is a modified starch used in glycogen storage diseases and is an excellent choice for a pre race carbohydrate source. The croissant is fine to eat as well, but I think the bigger issue is systematically taking a certain number of grams of carbohydrates per hour. No matter how fat adapted a person is, there is always going to be some requirement for carbohydrates during the race (of course this depends on intensity). In this example, I would suggest that 50 to 150 grams of carbohydrate per hour should be consumed (some studies even say 40 grams). These carbohydrates can come from drink, gels, bars or real food. A reasonable goal is to just eat 25 g of carbs anytime you eat or drink 4 times within the hour. This gives you 100 g per hour and is a good starting point.
  2. Not feeling hungry. The fact that you did not feel hungry during the race is a sign that you are fat adapted. However, in any event over 2 hours it is prudent to take a consistent amount of carbohydrates and adequate fluids. So whether you feel hungry or not you should be taking in something.
  3. In the race bonk. The most likely reason for this happening is that you didn’t take enough consistent carbohydrates during the race. The Vespa’s definitely helped, but it is apparent that she needed more. In this case, playing Monday morning quarterback, it would have probably been enough for you just to drink a Coke at the halfway point of the run. So this would have more to do with the timing of carbohydrates and whether you took in enough.
  4. There were no mention of taking salts, but depending on the person, this may or may not have been a factor.