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How to Carb Load On the Low FODMAP Diet

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How to Carb Load On the Low FODMAP Diet

Did you know that carb loading before a marathon or another type of endurance sporting event can help you improve your performance? And yes, it is possible to carb load and feel great even if you have IBS! Here is how to carb load on the low FODMAP diet.

view of a male runner's legs as he runs down a road
Did you know that carb loading before a marathon or another type of endurance sporting event can help you improve your performance?

Building Up Glycogen Stores

During a long distance race (90 minutes or longer) such as a marathon, a triathlon, or another endurance sporting event, the body uses glycogen (carbohydrate) stores as its main source of fuel. When glycogen stores in the muscle and the liver become depleted, the body then needs to rely on fat to produce energy.

Fat is a less effective fuel than glycogen, because it requires a lot more oxygen to produce the same amount of energy.

Therefore, the sooner you run out of glycogen, the sooner you will feel tired and will have to slow down. Carb loading a few days before a marathon or an endurance event can help optimize performance. It consists of modifying your diet and training to maximize the amount of glycogen in your muscles.

A proper protocol followed faithfully will nearly double your muscle’s glycogen content! It is estimated that carbohydrate loading can improve performance over a set distance by 2 to 3%.

how to carb load on the low FODMAP dietHow to Carb Load On the Low FODMAP Diet – and Not Trigger IBS

According to the most recent research, it is recommended to reduce training volume the days before the race (what’s known as tapering) and adopt a carbohydrate rich diet (7g to 12g of carbohydrates per kilogram of body weight) for three days before the race. Now that’s a lot of carbs! It’s about 70 to 80% of your calories as carbohydrates.

This can be challenging if you are following a low FODMAP diet and there are a lot of carbohydrate rich foods that trigger your GI symptoms.

Here are 5 tips to help you succeed:

1)   Stick to foods that you can tolerate very well

Identify the carbohydrate rich foods that you know you tolerate very well and stick to those foods as much as possible. Even if that means eating the same foods a few times, it’s only for 3 days… Better be safe than sorry!

2)   Don’t overeat!

Understand that you do not need to eat more than usual. Eating too much will make you feel full and sluggish. Instead, you need to substitute fat and protein with carbohydrate. For example, if you usually put some avocado in your salad, put some blueberries instead. If you usually snack on almonds, snack on rice crackers instead.

If you usually eat eggs for breakfast, eat oatmeal or gluten free waffles with maple syrup instead. You need to modify your food choices, not the serving sizes! Eat smaller meals and snacks more often – at least 6 times per day – to avoid feeling too full. Make sure to stick to low-fat foods.

3)   Plan your carb loading ahead of time

Plan your carb loading ahead of time to avoid being caught off guard.If you need to travel for your race, make sure to bring high carbohydrate low FODMAP snacks with you such as rice cakes, rice crackers, gluten free bagels, dried banana chips, bananas, instant oatmeal and low FODMAP cereal such as Cheerios or Chex.

4)   Drink some of your carbs

During carb loading, carbohydrate needs are so high, which makes it hard to meet your needs with solid foods without feeling too full. That is why drinking some of your carbs is a good idea! Choose a sweet drink that you can tolerate well, such as the one that you usually drink during a long workout.

Gatorade is usually well tolerated by people that have IBS. You can also drink cranberry juice, which is low FODMAP, or again you can try our strawberry lemonade.

5)  Do not try something new on race day

The morning of the race, eat what you are used to eating before exercising. You should test different breakfasts options in advance so you can find a breakfast that you can tolerate well.

You should also carry your own supplements such as gels and sports drinks or make sure that you are familiar with the ones that are provided on the race course.

Here is a low FODMAP carb loading one-day meal plan to guide you*:

*The menu is based on a 3000-calorie diet. Serving sizes should be adjusted according to one’s individual energy needs. Don’t hesitate to consult a Sports Dietitian to get a personalized meal plan.


  • 3 gluten free waffles or pancakes, 4 inches (10 cm) diameter each (made with gluten free flour and lactose free milk)
  • 2 tablespoons of blueberry compote or 1 tablespoon maple syrup and ¼ cup (64 g) blueberries
  • 1 orange
  • 1 cup coffee with 2 teaspoons sugar

AM Snack:

  • 15 dried banana chips or 1 banana or 1 slice of banana bread
  • ½ cup (125g) lactose free low fat strawberry yogurt
  • 1 cup (250 ml) Gatorade


  • ½ cup dry (100g) rice (1½ cup cooked)
  • 2 oz (60g) baked chicken
  • ½ cup (100g) green beans
  • 1 cup (250 ml) cranberry juice or strawberry lemonade

PM Snack

  • 3 rice cakes with 2 tablespoons (30 ml) orange marmalade or strawberry jam
  • 1 cup (150g) grapes
  • 1 cup (250 ml) Gatorade


  • 1 ½ cup (150g) gluten free pasta
  • 1 cup (250 ml) tomato sauce
  • 1 cup (240 ml) of cranberry juice or strawberry lemonade
  • ½ packet (240 ml) lime Jello

Evening Snack


  1. Monash University. Low FODMAP smartphone app. Retrieved from 
  2. Jeukendrup (2016) Carb Loading: What is New? 
  3. Atkinson et al. (2011) Pre-Race Dietary Carbohydrate Intake can Independently Influence Sub-Elite Marathon Running Performance. Int J Sports Med; 32: 611– 617.
  4. Australian Institute of Sports (2004) Carbohydrate Loading.

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