Like HowStuffWorks on Facebook!

How Triathlon Nutrition Plans Work


Food Intake for Triathletes
A triathlete may need to nearly double caloric intake.
A triathlete may need to nearly double caloric intake.
Photo courtesy of the Department of Defense

An endurance athlete's caloric needs are high, evidenced by Michael Phelps reported pasta-and-pizza diet [source: ESPN]. An average 160-pound human being needs between 2,000 and 3,000 calories per day. An average 160-pound triathlete needs between 3,000 and 4,000 calories per day [source: TNO].

For triathletes, eating too little doesn't just mean losing weight; it means a poor finish. If they don't eat enough, it affects performance. A car can't drive without fuel. An inadequate number of calories (and fluids) can result in fatigue and perhaps injury, or maybe just a terrible training session or race.

Performance in both training and racing relies a great deal on taking in the right nutrients. In general, a triathlete needs to pay specific attention to intake of:

  • Calcium: supports muscle and bone health
  • Carbohydrates: the fastest energy supply for muscles with 4 calories per gram
  • Fat: a more concentrated energy source with 9 calories per gram
  • Protein: essential for building and repairing muscle with 4 calories per gram
  • Iron: needed in red-blood-cell and muscle-cell production, as well as the conversion of food to energy (metabolism)
  • Vitamin B complex: needed for metabolism and to produce red blood cells (which transport oxygen)
  • Vitamin C: supports connective-tissue and bone health while also acting as an antioxidant (prevents free-radical cell damage -- triathletes take in more oxygen when exercising, leading to increased production of free radicals)
  • Vitamin E: also an antioxidant
  • Water: transports nutrients and keeps the body from overheating
  • Zinc: supports energy production in muscle cells

Of these items, the ones most specifically tied to endurance athletics are carbohydrates, proteins, fats and water. Triathletes use more of these nutrients and have to make sure they balance activity levels with intake. For an average triathlon training day, Bob Seebohar of the Colorado Center for Altitude Training and Performance recommends:

  • Carbohydrates: 1-10 grams per kilogram of body weight
  • Protein: 1.2 -- 1.6 grams per kilogram of body weight
  • Fat: 1 gram per kilogram of body weight
  • Water: at least 10-12 cups per day

[source: Seebohar]

This balance is key to any successful triathlon nutrition plan. But 3,000 to 4,000 calories per day doesn't mean 3,000 to 4,000 calories of anything. Here's where the real plan begins…


More to Explore