Ironman Diet: 8 Nutrition Rules, Advice, and Tips to Keep You Going


When you’re training for a high-mileage Ironman triathlon, fueling up the right way isn’t just about what you consume. It’s about how you consume it, so you can maximize the benefits of workout recovery and race-day performance. This is especially true for Ironman newbies—because if you’re not properly nourished, you’ll fade faster than Lindsay Lohan at an all-night happy hour.

“For endurance races, especially the Ironman and Half Ironman, diet is critical,” says Penny L. Wilson, a registered dietitian with the Ironman Sports Medicine Institute. “Especially on race day, you’re out there for 12 to 17 hours. You have to be able to fuel your body to go that long.”

Wilson says to test your diet early on in training and tweak your intake until you find a near-perfect nutritional balance that satisfies your body’s needs. “If it works good in training, it wont work at the race,” she says, “It needs to be great.”

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Though everyone’s nutritional demands vary, here is Wilson’s general, no-fail advice. Follow her rules to build a diet plan that works for you—and be a well-fueled endurance machine by the time race day rolls around.

Eat lean protein within 45 minutes of a workout.
A good source of lean protein (with essential amino acids) is the ultimate recovery food—when consumed within 45 minutes of exercise, it repairs microscopic damage to your muscle tissue caused by working out. So depending on when you train, incorporate lean chicken, fish, nuts, and beans into a post-workout meal, or have a tall glass of low-fat chocolate milk as a snack. Its mix of protein and carbs is perfect for rapid recovery. (A note of warning from Wilson: With its lower protein count, chocolate almond milk doesn’t count.)

Fill up on fruits and veggies.
This may sound obvious, but suppressing your appetite with the best stuff on earth is key—fruits and raw vegetables (loaded with phytonutrients) provide a great source of fiber and antioxidants essential to digestive and overall health. So snack on apples, bananas, and green veggies (like spinach, zucchini, and kale), which are rich with iron—another key mineral for athletes.

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Load 1/3 your plate with complex carbs.
Energy is essential for an endurance athlete, and nutrient-dense carbohydrates—like potatoes, rice, and whole-grain pastas and cereals—replenish glycogen and stimulate insulin production. It is important, however, to eat those complex carbs in moderation. Wilson recommends reserving a third of your plate at big meals for starch (think: a side of potatoes and rice), balanced by equal parts protein and veggies.

Stoke your metabolism with a good breakfast.
Breakfast will always be beyond important. Period. And Wilson recommends a good balance of protein, carbs, and fat to keep you full the longest. Two solid options: Greek yogurt with granola, nuts, and dried fruit or breakfast quinoa, which can be served just like oatmeal. The quinoa packs twice as much as protein as normal cereal, and as an added bonus, it’s gluten-free.

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Hydrate with water and sports drinks.

Wilson recommends water with added electrolytes or low-sugar sports drinks as your most solid hydration options. The key is finding a flavor you like, and mixing it up throughout the day if necessary. This will spice up your routine and give it more variety, so you’ll be more likely to stay properly hydrated.

Skip fried foods.
This should be a no-brainer, but many people may not realize just how detrimental fried foods are to the endurance athlete. Fried foods aren’t just high in fat and calories, but depending on what’s being fried, most have almost no nutritional value. Pair that with their trans-fatty acids and the risk of increased blood pressure—and there is no reason to “reward” yourself with fried food if you’re serious about training.

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Beware of energy drinks and bars.
While they are marketed as nutrient-rich snacks—or even as meal replacements—most protein or energy bars are essentially candy bars (high in fat and calories) with sport-specific packaging. (Take this edible oxymoron, the Snickers Marathon Bar,  for example: It has 7 grams of fat and is loaded with sugar.) Same goes for energy drinks. Many of them include high amounts of sugar and caffeine. While you’ll get that short-term boost, the crash will slow you down, so Wilson suggests exercising caution.

Set your race-day plan early.
As you start to follow these other Ironman nutrition rules, you should begin to figure out what your body needs (how much water, how many calories, etc.)  to perform at its best—so use that knowledge to create a race-day fuel plan that starts up to 24 hours beforehand and runs through the daylong race. You’re definitely going to need carbs to burn during the grueling bike and run, and accessibility and portion-size will obviously be key. Wilson recommends a good ole’ peanut butter and jelly sandwich on whole-wheat bread or smaller snacks, like Clif Shot Bloks  and Sport Beans.

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