Run nutrition strategy for an 8-hour run

Ultra-marathon running and race nutrition go hand-in-hand. It's not possible to perform well in a long run without the appropriate fuel for a couple of reasons. The first is that the energy expenditure over a long run is very high and some of that energy needs to be replaced. In my 8-hour run my heart rate monitor estimated that I used 3,938kCal. The second is that a long day out also means that some normal meals will be missed putting the body further into deficit. I started my run at 6AM and finished just before 2PM in which time I would normally eat breakfast and lunch.

It's not easy to figure out race nutrition. I've had problems in the past and tried all sorts of different products and strategies. I have friends who have tried similar strategies to me and those strategies have not worked for them. As a crew member and spectator at UTMB I saw lots of people with stomach issues (I think this was from the tremendous shaking on the long descents). I'm pleased that the strategy I have now is working for me and this post is to share the plan so anyone can try it and use it.

There are three underlying principles that I built my plan on. I think that these rules apply to everyone and that they need to be followed as closely as possible. How each athlete chooses to adhere to them and fuel their running is a personal choice (in terms of products and timing), but these principles are a great place to start building a race nutrition strategy.

(1) The body can assimilate between 175kCal/hr and 325kCal/hr through the digestive tract. This is far below the energy expended during running so energy will have to come from other sources within the body (glycogen stores and fat). However, the most efficient and effective way to provide energy is through a balance of these sources that include stores within the body and the food and drinks taken during the run. Keeping the nutrition coming into the body through eating and drinking during a race is important.

(2) Different fuels and products have different impacts on the level of insulin in the blood and the rate at which energy will become available. A measure of the rate at which each item ingested delivers energy to the muscles is the glycemic index (GI). Low GI foods are more stable and take longer to deliver energy to the muscles; nuts, some dried fruit, meats and vegetables are low GI. High GI foods deliver energy to the muscles very quickly; sugar and colas and fruit are high GI. High GI foods need to be taken very consistently to avoid spikes and dips in energy, however, they can be good to give a fast boost in energy when it's needed. My principle is to take low GI food and products in the earlier parts of a long run and slowly phase in higher GI products towards the end of the run when the effort becomes more intense.

(3) There are lots of options to put fuel and energy into the body. While it's possible to meet energy requirements during an 8-hour run by eating 16 gels of the same flavor, the gels later in the day are going to taste bland and boring (no matter how much you love the vanilla, coffee, peanut butter or salted caramel flavor!). My final principle is to take a variety of different fuels and products during a race, in terms of both flavor and texture, to keep things interesting and improve adherence to the nutrition strategy. [sometimes this principle cannot be followed due to specific race requirements like carrying all the fuel for a multi-stage race. Here it makes sense to carry the lightest products possible even if they provide little variety.]

In practice for me this means eating about 200-250kCal per hour starting with bars and energy tablets and then switching to gels and chews later. The energy input is correct (1), the products during the first part of the race are low GI with some high GI products towards the end (2), and there is a variety of things for me to eat (3).

I'm sponsored by 32Gi so I have great access to a range of their products for my running fuel. I believe in the high quality of the 32Gi products, I like the range of options that I can use during a training and racing and the principles behind the company and product range match what I try to do. Nevertheless, the race nutrition strategy below is based on the three principles I wrote about above and it can be used with any products. Obviously I would recommend using 32Gi if it's available!

Food for 8 hours of running (loop 1 on the left, loop 2 on the right).

Pre-run

One hour before the run I ate and drank the following:

1 bottle of Recover
1 Foodbar
I cup of coffee
1 Trumag tablet
1  caffeine tablet 150mg

kCal = 428

First loop (3:45, 28km)

On the first loop of the run I ate the following:

0.5hrs: half a Foodbar
1.0hrs: 3 Endure Tablets, quarter a packet of Chews
1.5hrs: half a Foodbar
2.0hrs: 3 Endure Tablets, quarter a packet of Chews, caffeine tablet 150mg
2.5hrs: half a Foodbar
3.0hrs: 3 Endure Tablets, quarter a packet of Chews
3.5hrs: half a Foodbar

Loop total = 728kCal at 194kCal/hr

On this first loop I had no problem at all sticking exactly to the plan and eating as I was supposed to. I took enough food for four hours and finished the loop in about 3:45 so I had one more set of food to eat when I arrived at the checkpoint. I loaded my pack with food for the second loop and I took a Trumag tablet in the checkpoint.

Second loop (4:00, 28km)

On the second loop I ate the following:

4.0hrs: 1 coffee gel
4.5-4.75hrs: 2 Endure Tablets, half a pack of chews, caffeine tablet 150mg
5.25-5.5hrs: 1 coffee gel
6.0-6.25hrs: 2 Endure Tablets, half a pack of chews, caffeine tablet 150mg
7.0hrs to end: Endure tablets, Chews about every 15 minutes to the end

Loop total = 724kCal at 181kCal/hr

This loop started off well although my run nutrition strategy went a little off plan at about 4.5hrs. There was a big 900m climb about half an hour after the checkpoint at the end of the first loop. I was climbing hard and my hands were full with my poles so I took longer than expected to eat the food I was supposed to at 4.5hrs. I stretched out the time in which I ate a little and from then on each time I was supposed to eat took a little longer with a period of about 15 minutes to 20 minutes for me to eat all the required food. At the end of the run during the last hour I was eating little snacks, an Endure tablet or a chew every now and then to get me to the end. It wasn't as disciplined as I would like to be, but it worked out OK.

Run total = 1,453kCal at 187kCal/hr


Finishing up just under 8 hours and feeling good.

In this run I only drank water and used solid food products for my nutrition. I usually like to use 32Gi Endure drink and will test that out as an alternative to the Endure tablets. During this run, however, I was testing out a new hydration system (soft flasks) and I wasn't sure about how much I would drink due to the colder temperatures and all the shaking on the downhills might not feel too good with a stomach full so I kept my nutrition an dehydration separate. This way I knew that I could manage my nutrition intake independent of what I drank. I carried two 500ml soft flasks of water and drank from them when I was thirsty.

Please feel free to ask any questions in the comments below.