Inside the Desert: How The GU Roctane Performance Lab Prepared and Fueled Two Olympians for Marathon des Sables

Inside the Desert: How The GU Roctane Performance Lab Prepared and Fueled Two Olympians for Marathon des Sables

Inside the Desert: How The GU Roctane Performance Lab Prepared and Fueled Two Olympians for Marathon des Sables 

By: Roxanne Vogel, PhD 

When you take on the Marathon des Sables (MDS), you’re not just racing. You’re performing, adapting, and surviving for seven consecutive days in one of the harshest environments on earth, the Sahara Desert. In a place where temperatures regularly exceed 120° F, competitors must endure heat, sandstorms, and unforgiving terrain all while running up to 100k (62 miles) per day. 

For elite athletes Des Linden and Magda Boulet, success in the Sahara wasn’t just about fitness, it was about preparation and precise planning. It meant dialing in a personalized nutrition and hydration strategy, mastering performance under constant heat stress, and minimizing every ounce they had to carry in their packs. Here’s how The GU Roctane Performance Lab approached it. 

Start in the Lab, Validate in the Heat. 

Every decision began with data. Through Performance Lab testing and environmental simulations, I built a complete metabolic and hydration profile for each athlete, drawing from multiple data sources, including: 

  • Sweat rate and sodium losses under heat stress
  • Caloric demands at race pace
  • Carbohydrate versus fat utilization in simulated desert conditions 

But data alone isn’t enough, you must also prepare the entire system. 

Heat Training 

First, I knew we needed to prepare for the specific demands of the race. Because heat is a major factor in MDS, both athletes completed a progressive heat training protocol to: 

  • Decrease cardiovascular strain and increase heat tolerance
  • Improve sweat efficiency and electrolyte conservation
  • Practice our fueling strategies where they mattered most, in the heat 

Heat training sessions included both passive (sauna or hot tub) and active (training in the heat or overdressed) heat exposures which progressed in duration over the course of four weeks. Using CORE temperature sensors, I monitored each athlete’s heat training progress and ensured the targeted adaptations were happening gradually and effectively. 

The Reality of Racing in Extreme Heat 

In the heat, the gut is under increased stress. Digestion slows. GI issues multiply. Even the idea of consuming calories can feel overwhelming. So, I made a strategic decision to focus on liquid calories for the bulk of their “moving food” intake. The fueling strategy centered around simplicity, ensuring adequate hydration, and promoting GI comfort. The obvious solution was GU Roctane Energy Drink Mix. Instead of relying on gels or solid foods, which weigh more on a calories-per-ounce basis, we used a primarily powdered drink mix fueling approach which also helped shave weight from their packs. 

Why GU Roctane Drink Mix worked: 

  • Delivered carbs, electrolytes, amino acids, and fluid all at once
  • Reduced GI distress during high heat exposure
  • Matched energy demands from lab testing
  • Improved execution: no guesswork, no juggling multiple products 

The target was one serving per hour of movement, providing 60 g of carbohydrate, 320 mg sodium, and 900 mg BCAAs. In an environment where small mistakes become big problems, simplicity equals performance. 

Recovery Between Stages: Where Races Are Won 

MDS is a multi-day race. What you do after each stage determines how you show up the next day. So I had Des and Magda focus on four daily recovery priorities: 

  • Restore glycogen quickly
  • Maintain muscle under catabolic conditions
  • Reduce soreness and fatigue
  • Rehydrate
  • GU Roctane Protein Recovery Drink Mix 

A critical piece of the plan for recovery was our GU Roctane Protein Recovery Drink Mix, which was fast, palatable, and easy to consume (even with low appetite). With carbohydrates, electrolytes, and protein all in one, it also helped support muscle repair, glycogen replenishment, and rehydration. Plus, it was flexible enough to double as part of breakfast, mixed into their overnight oatmeal. Each day, they had a serving to start the day and a serving after they finished moving. 

BCAAs: Targeted Muscle Support 

With massive caloric deficits and repeated loading, GU Roctane BCAA capsules were used before and after stages, supplying and additional 4.5 g BCAAs to help reduce muscle soreness and promote recovery while supporting resilience across consecutive days. 

The Pack Weight Problem  

At MDS, athletes carry their own food, sleep system, and clothing for all seven days. That means every ounce matters. I planned out their daily nutrition with three key goals: 

1. Maximize Calories per Ounce 

  • Using mostly powdered drink mixes and dehydrated foods 

  • Concentrated energy density by adding healthy fats to round out their daily calories  

2. Eliminate Bulk 

  • Packed Roctane Drink Mix into sandwich bags to minimize packaging 

  • Reduced unnecessary weight and volume by making all meals cold water prep, eliminating the need for a stove or heat source 

3. Keep Athletes Eating 

Because appetite drops in the heat, we: 

  • Rotated between different flavors of breakfasts, drink mixes, and dinners across stages 

  • Included savory options (like mashed potatoes) to reduce flavor fatigue 

  • Incorporated more citrus-type flavors that are lighter on the palate and satiate thirst over indulgent flavors (chocolate, caramel, etc.) which are less appealing in hot conditions 

The goal wasn’t just creating the perfect plan on paper, it was ensuring they could maintain their fueling deep into the race by providing a variety of palatable, familiar food options. 

The Secret Weapon 

In extreme heat, perception can limit performance just as much as physiology. That’s where MC-318 comes in. 

What is MC-318? 

A patented*, menthol-based energy gel from GU that: 

  • Creates a strong cooling sensation in the mouth and airways when consumed 

  • Improves thermal comfort 

  • Helps athletes feel perceptually cooler  

Used strategically while running during the hottest parts of each stage, GU Roctane MC-318 helped Des and Magda feel cooler and more comfortable. While not yet commercially available, it’s already been tested in some of the world’s toughest, hottest races, including MDS, Badwater 135, and Western States 100. Athletes who’ve used it have called it game changing. 

The Takeaway 

Racing in extreme environments doesn’t just test your fitness, it tests your entire system. The athletes who succeed are the ones who train their gut as much as their muscles, adapt to the environment before race day, and simplify their fueling to execute under stress. Because in the harshest environments, performance doesn’t happen by chance; it’s built through preparation, precision, and purpose. 

 

*US Patent No. 11,850,217 B2 

Back to blog