Your race week diet can be the difference between a personal best and a DNF. Dial it in with this plan from sports dietitian Jeff Rothschild.

When you’ve spent months training for a race, the last thing you want to do is screw it up at the last minute by eating badly. But the truth is that by the morning of your event, you may have won or lost the nutrition game already. “I actually don’t get too picky on people’s race morning foods. Whatever they’re comfortable with,” says Jeff Rothschild, a registered dietitian at TriFit Performance Center in Santa Monica, California. “I get really picky during the three days out. Race morning is just topping up the tank.”

With so much riding on how you eat, it pays to plan out your taper-week meals in advance, especially if you’ll be traveling to your race. For the first few days of the week, Rothschild recommends that athletes eat similarly to their normal diet, with about 55 percent of calories coming from carbohydrates and the remainder split evenly between protein and fat.

A few days before the gun, switch to a carb-load diet to boost glycogen stores—and your available energy—for the race. (Exactly how long in advance depends on the length of the event: Rothschild recommends one day for an Olympic-distance triathlon, two days for a half-Ironman, and two to three days for a full Ironman.) Pay attention to your plate here. “Most people don’t carb load appropriately,” Rothschild says. “Their diets may include too much fat, fiber, protein, or overall calories, while consuming too few of the right kinds of carbohydrates.” At this point, a little over 70 percent of your calories should be coming from easy-to-digest carbs like white rice and potatoes.

If you’re used to getting most of your calories in one big meal, be prepared to make adjustments. You won’t be able to consume enough carbohydrates during dinner the night before a race. Plan on eating a bigger than normal breakfast and lunch, and fitting in snacks between meals.

This meal plan from Rothschild is designed for an average-size male athlete racing a half-Ironman. Your actual needs will vary based on your size, experience level, and race plans; consult a dietitian for optimal results.

Key

Protein
Lean animal protein (salmon, chicken, beef sirloin)
Carb
Baked potato or white rice
Pretzels
25 mini pretzels
Juice
12 ounces fruit juice or coconut water
Sports drink
12 ounces sports drink
Salad
Mixed green salad
Full Breakfast
All of the following: 2 eggs, 1 1/2 cups oatmeal, 2 slices toast with jelly, 1/2 avocado
High-Carb Breakfast
All of the following: 2 eggs, 3 cups oatmeal, 2 slices toast with jelly, 12 ounces fruit juice
Bar
Energy bar with 200-250 calories
Fruit
Banana or 1 cup canteloupe, etc.

Sunday

Breakfast
Full Breakfast
Morning Snack
Fruit
Lunch
Carb x 1 1/2 cups, Protein x 5-6 ounces, Pretzels, Salad
Afternoon Snack
Bar of Fruit
Dinner
Carb x 1 1/2 cups, Protein x 5-6 ounces, Salad

Monday

Breakfast
Full Breakfast
Morning Snack
Fruit
Lunch
Carb x 1 1/2 cups, Protein x 5-6 ounces, Pretzels, Salad
Afternoon Snack
Bar of Fruit
Dinner
Carb x 1 1/2 cups, Protein x 5-6 ounces, Salad

Tuesday

Breakfast
Full Breakfast
Morning Snack
Fruit
Lunch
Carb x 1 1/2 cups, Protein x 5-6 ounces, Pretzels, Salad
Afternoon Snack
Bar of Fruit
Dinner
Carb x 1 1/2 cups, Protein x 5-6 ounces, Salad

Wednesday

Breakfast
Full Breakfast
Morning Snack
Fruit
Lunch
Carb x 1 1/2 cups, Protein x 5-6 ounces, Pretzels, Salad
Afternoon Snack
Bar of Fruit
Dinner
Carb x 1 1/2 cups, Protein x 5-6 ounces, Salad

Thursday

Breakfast
High-Carb Breakfast
Morning Snack
Sports Drink, Bar
Lunch
Carb x 2-3 cups, Protein x 4 ounces, Pretzels, Juice
Afternoon Snack
Sports Drink, Fruit
Dinner
Carb x 3 cups, Protein x 4 ounces, Juice

Friday

Breakfast
High-Carb Breakfast
Morning Snack
Sports Drink, Bar
Lunch
Carb x 2-3 cups, Protein x 4 ounces, Pretzels, Juice
Afternoon Snack
Sports Drink, Fruit
Dinner
Carb x 3 cups, Protein x 4 ounces, Juice

Race Day!

Breakfast
Race Day! Normal breakfast three hours before start time