Fueling for a Spartan Ultra Beast

FYI: I am not a doctor or nutritionist, but throughout my training and research this is what I’ve found out.

A Spartan Ultra Beast may take well over 8 hours to complete. Therefore it is crucial to be consuming nutrients throughout the race that will provide you with the needed energy to complete the race. During your training it is very important to experiment with as many different gels, bars, electrolytes, salt tabs, and real food as you can. You need to find out what works for you as every individual is different. What works for me or your friends may not work for you. As you experiment with different products you may find certain products lead to gastrointestinal issues (GI issues), such as cramping, vomiting, and diarrhea. Therefore I can’t stress enough how crucial it is that you figure out what works best with your body in training, so you do not experience any sort of GI issues on race day.

When deciding how much fuel and when to ingest fuel/food you need to have a rough idea of how many calories you will be burning every hour and how many calories your body can absorb per hour. While running you may burn anywhere from 400-600 calories per hour, however the human body is only able to absorb 240-280 calories per hour (Aschwanden, 2008). Therefore your body will be burning calories much faster than your body will be able to absorb them. This will put your body into a calorie depleted state. By ingesting calories you will be able to prolong the depletion process, allowing you to remain active for longer. When picking your calories be sure to pick a variety of flavours to keep your pallet entertained and prevent flavor fatigue. Flavor fatigue is experienced when you ingest the same thing over and over during a race and you eventually become repulsed by the thought of ingesting it again (i.e. only having chocolate flavoured gels because they are your favorite, but they might not be your favorite 5 hours into the race). If you keep ingesting different flavors this will keep your pallet entertained and prevent flavor fatigue.

In addition to the amount calories you are ingesting you’ll also need to be aware of the amount of salt you are consuming. As you sweat you will be losing sodium and other salts from your body and if you don’t replace these salts you may be at risk of cramping. It has been suggested that consuming 200-500 mg/hr to as much as 1000 mg/hr in some cases, will be enough to ward off any unwanted affects caused be salt depletion (Stevenson, 2012).

You’ll also want to be very careful of how much water you drinking. If you don’t drink enough water you’ll become dehydrated, however if you drink too much water you are at the risk of entering hyponatremia which can be life threatening. Drinking to thirst in general is a good rule to follow but if you’re like me you’ll find that you may not be drinking enough and begin to feel the onsets dehydration. That’s why during my longer runs I’ll take small sips (no more than a mouthful) of water every 15 minutes or so, as well as taking a cup of water at every aid station (in a race). My advice about hydration is to not overthink it and take in small amounts of water as needed.

Here is a link to a very informative podcast about Hydration

Key Points

  • Your body can only absorb 240-280 calories per hour
  • Have a variety of flavors
  • Consume 200-500 mg/hr of salt
  • Drink to thirst, or small sips every 15 min
  • Research! There is tons of data out there and try to learn as much as you can about the science and your body, to determine what works for you.

My Ultra Beast Nutrition Plan

Gu Energy Gel

Nuun electrolyte tablets

Clif Builder Bars

Real Food (Peanut Butter, Jelly, and Bacon Wrap)

I carried 1.5 litre of water mixed with 3 Strawberry Lemonade Nuun tablets (1 tablet/500 ml) and aimed to drink all 1.5 litres of water per lap. I took small sips of water roughly every 15 minutes, as well as whenever I consumed an energy gel. My salt intake was ~ 550 mg/hour (Nuun in my water, and Gu Energy gels/other food).

Gu Energy Gels were my main source of calories. I had my first gel 45 minutes into the race, my second gel at 90 minutes, and then I consumed one gel or another source of calories every 30 minutes until the end of the race. My goal was to consume roughly 200 calories per hour (each Gu gel is ~100 calories). On my first lap my sole source of calories was the Gu Energy Gels. On the second lap in addition to the Gu Gels I consume one Clif Builder Bar (Clif’s protein bar), and a peanut butter, jelly and bacon wrap (this was a perfect treat halfway through the second lap). The energy gels I used contained caffeine. It is important to continuously consume caffeine once you begin to ingest it during a race, because as soon as you stop you will quickly feel effects as you come off the “caffeine high”.

In my drop bin I had 1.5 L of Nuun infused water (allowing for quick refill) and much more energy gels, bars and food than I needed. In a race like this you don’t know entirely what to expect so it is a good idea to pack extras, because you most definitely don’t want to need something and not have it.

Dial in your nutrition, and you’ll conquer the Ultra Beast!



  1. You said that the body can only consume 240-280 calories per hour. So why did you have a peanut butter and jelly sandwich at the halfway point?

    1. Good question. I didn’t eat the entire sandwich at the halfway point. Instead I brought it with me on the second lap and took bites of it at specific intervals (~30 min), in order to not exceed the calorie limit. Also note some people out there consume more than the above suggested amount. So be sure to play around with it and see what works with you.

Leave a Reply

Your email address will not be published. Required fields are marked *