Over the past 20 years, we've had the opportunity to observe the fueling habits of many thousands of athletes. While the fueling protocols have varied tremendously, here are facts which are repeated consistently in every case:

Athletes Who Experience Fueling Success: Of the athletes who have contacted us to report success (no fuel-related, performance-inhibiting problems and consistent energy levels), the following factors occur with reliable consistency:

• Fluid intake was under 30 fluid ounces/hour.
• Sodium intake was between 300mg and 600mg/hour, with 400mg/hr being the most often reported dose.
• Caloric intake less than 300 cal/hour.
• Moderate simple sugar intake, favoring complex carbs.
• Body weight at finish decreased no more than 2-3%.

Athletes Who Experience Fueling Failure: Athletes who suffered poor performance due to fueling-related problems reported consumption as follows:

• Fluid intake over 30 fluid ounces/hour.
• Caloric intake exceeded 300 cal/hr.
• Consumed primarily simple sugar-based fuels, causing stomach ailments.
• Sodium intake above 600 mg/hour.
• Body weight at finish was hyper-hydrated with weight gain from 1-2%, or dehydrated at over 3% body weight loss.

What you should derive from this data is that while there is no one-size-fits-all fueling formula. When it comes to fueling for endurance performance, less is best.