3 Step Guide to Carb Loading for Fast Marathons

Estimated read time: 4 minutes

Hey! - Performance Nerd Jonah here.

Do you want to improve your marathon time by 3% overnight?! That’s the difference between a 3:00 and a 2:55 marathon! 🏃‍♀️💨 

Enter Carb Loading. The #1 hack to rapidly improve your marathon.

But, 90% of runners get carb loading WRONG.

The Biggest Carb Loading Mistakes I see:

• Not eating enough carbs the day before the race

• Carb loading for 5 days (too long)

• Avoiding carbs early in race week

Here's how to actually carb load, step by step:

1) Exactly how many carbs should you eat? (13 Bagels)

For a marathon, 8-12 grams of carbs per kg or 3.6-5.5 grams per pound of bodyweight is best.

We don’t need to overload for 5 days. We can fill our carb stores in 1-2 days.

For example, I weigh around 77 kg (170lb). The 2 days before my marathon I intake 800 GRAMS OF CARBS per day.

That’s 13 bagels. I’m sending the bagel store owners’ kids to college. 🥯

If you’re new to carb loading or have had stomach issues before, start closer to 8 grams.

DRINK YOUR CARBS

Use drink mixes or liquid carbs (Juices)! Drink mixes and juices are easily to digest carbs and don’t fill up your stomach.

Look for drink mixes that are mostly simple sugars and have some fructose.

My favorites:

• Raw Fuel

• Maurten

• Precision Fuel

Carb Loading Table

2) Avoid Foods High in Fat and Fiber

DO NOT eat your vegetables.

Okay you should be, but carb loading and broccoli don’t mix (Sorry mom).

Food high in fiber, like vegetables and beans, are harder to digest.

Avoid them in a carb load.

Fats are high in calories and we don’t need to overload fat stores as we already have plenty.

It’s best to reduce fat calories and replace those with carbs so we don’t overeat.

Foods to Avoid:

• Uncooked Vegetables

• Leafy Greens (Spinach, Kale)

• High Fiber Vegetables (Carrots, Broccoli, Brussel Sprouts, Cauliflower)

• Beans

• Added Oils

• Fried Foods

• Full Fat Cheeses

• Full Fat Dairy Products (Milk, Yogurt, etc.)

• Fatty Meat (bacon, sausage, ribs, pork, most red meat, most deli meat)

• Alcohol

3) Stick with Foods You’re Used to

I have a lot of regrets.

The big daddy pizza the night before the Boston Marathon last year is definitely one of them. Mile 12 still gives me nightmares.

Stick with simple foods in the carb load that you know your stomach feels good with!

The pizza was really good though. #worthit

Top Carb Load Foods:

• Pasta

• White Bread

• Rice / Rice Cakes

• Gatorade or High Carb Sports Drink

• Juices

• Bagels

• Bananas

• Granola / Granola Bars

• Pretzels

• White Potatoes

• Jam / Jelly

• Cereal / Rice Krispies

• Honey

Practical Summary

• Aim for 8-12 grams per KG bodyweight

  • 8 grams if you’re just starting!

  • Use liquid carbs or drink mixes

• Carb load 1-2 days before the race

• Eat a normal amount of carbs early in a race week

  • There is no need to “carb-deplete” yourself

• Reduce overall fiber and fat content

  • Avoid vegetables, beans, whole-wheat products

  • Avoid heavy oils, fatty meat, and other high-fat products

• Stick to easy digestible foods your body is used to

Here is a quick video about carb loading on my instagram: LINK

Don’t forget: You + Science = AWESOMENESS 😎

Yours in science,

Jonah

Don’t forget to respond if you have any other questions about carb loading. Augie (pictured above) and I will get back to you!

References:

Podlogar T, Wallis GA. New Horizons in Carbohydrate Research and Application for Endurance Athletes. Sports Med. 2022 Dec;52(Suppl 1):5-23. doi: 10.1007/s40279-022-01757-1. Epub 2022 Sep 29. PMID: 36173597; PMCID: PMC9734239.

Bussau VA, Fairchild TJ, Rao A, Steele P, Fournier PA. Carbohydrate loading in human muscle: an improved 1 day protocol. Eur J Appl Physiol. 2002 Jul;87(3):290-5. doi: 10.1007/s00421-002-0621-5. Epub 2002 May 28. PMID: 12111292.