Q: I am doing my first 70.3 this month. How do I need to adapt my nutrition plan?
A: Graduating to the half-Ironman definitely requires some nutritional planning. I train my athletes to constantly ask themselves if they are ingesting adequate amounts of three key things during an endurance event such as a 70.3 or longer. Your new nutrition mantra: fluid-sodium-carbs!
Drinking adequate fluids is the most important nutritional factor in achieving your racing goals.
Aim to consume at least one bottle of fluid per hour on the bike.
Drink evenly; 6–8 ounces every 15–20 minutes to optimize gastric emptying and minimize sloshing in your stomach.
Test your individual sweat rate (determine this by weighing yourself nude before and after a 60-minute run with no fluids), factor in the environmental conditions, then adjust your fluid intake.
On the run, drink to almost match your sweat rate. Calculate approximate ounces needed per mile based on your realistic estimated pace. (For example: 24 ounces per hour at 7.5 minutes per mile pace, I’d need to drink 3 ounces every mile—three large swings!)
– Sodium is the key electrolyte you need to replace during a 70.3 event.
– Sodium content of sweat varies widely between individuals. Do you have tracks of dried salt on your face and body after a hard workout? If not, alternating between water and sports drink may be adequate for you. If you do, aim for mostly sports drink and always endurance formulas (such as Gatorade Endurance) or a customizable blend like Infinit) to ensure adequate sodium and prevent cramping.
– Consider additional sodium/ electrolyte supplementation with electrolyte tabs. There are many different tabs of varying “strengths,” so read the label and ask a sports dietitian to help determine the right amount for you.
– Aim for 30–60 grams of total carbohydrate per hour during the race.
– Count carbs you will take in through your planned sports drink.
– Add gels, energy chews or even carb-based energy bars (think Clif or similar) on the bike.
– Add gels or energy chews/blocks on the run too. Take them with water!
– Don’t stop fueling or hydrating until you have crossed the finish line!
Want to transform your triathlon knowledge, training, and performance? Check out 10 Weeks to Your Best 70.3—a complete training program led by top endurance coach Jim Vance—free with Outside+ membership!
Lauren Antonucci, R.D., is a board-certified specialist in sports dietetics, three-time Ironman finisher and the founding director of Nutrition Energy in New York City.