Amy Stephens
MS, RDN, CSSD, CDCES
Licensed dietitian
specializing in sports nutrition
and eating disorders
Menu
Guide to carb loading for a marathon
-
By Amy Stephens RDN CSSD
Sports Nutritionist NYC
The greater the amount of glycogen present in your body, the greater your body’s capacity to run faster for a longer period. Fully stocked glycogen stores can significantly enhance your ability to endure the 26.2-mile journey and potentially boost your performance by 2-3% (as noted by Hawley).
Over the course of a marathon training cycle, you train your body to adapts to running longer distances. Carbohydrates are important to runners because they are a significant source of glucose.
To support extended running sessions, glucose is broken down to provide energy to your working muscles. This glucose is stored within the body as glycogen and serves as the primary fuel source.
Achieving effective carbohydrate loading involves consuming ample carbohydrate-rich meals in the days leading up to your race to ensure your glycogen stores are at their maximum capacity. This requires careful attention to meal planning and food preparation as the race day approaches. Carbohydrate loading represents the final phase of your marathon training plan.
Over the three weeks prior to the marathon, gradually increase carbohydrates as you gradually decrease exercise. This can be anxiety producing, especially if you have to continue eating while logging fewer miles.
Purpose of carbohydrate loading:
- Increase muscle adaptations
- Top off glycogen to maximum capacity
- Improve performance
Change in weight:
- A shift in your body weight is probably a result of rising glycogen levels. Because glycogen retains water, you may observe a minor uptick in your body weight.
- Have confidence in your fitness level. A change in weight is unrelated to a decrease in physical activity.
- As you get closer to race day, you will be eating more carbohydrates than you’re used to and exercising less. It’s okay for your body to feel different.
- Even if you’re not trying to gain fitness, your body is still working to retain muscle.
- Instead of thinking about numbers and weight, think about which nutrients are important to crush your 26.2.
- There’s less of an emphasis on post-run refueling because your runs are less demanding.
How to eat during race week:
- Eat a diet rich in carbohydrates to top off glycogen stores. Follow the same diet plan you have been training with but add additional carbs to meals. Now is the time to resume eating carbs even if you’ve been following a low training pattern with limited carbs. By adding back carbs into your diet, your body will top off glycogen stores. Aim for 4-5 g carb/pound body weight per day. For a 150 pound person, that ‘s about 600 grams of carbohydrate. Include: bread, pasta, rice, potatoes, oats, cereals, fruit, beans, and lentils.
- It’s okay to gain a couple of pounds this week. Carbohydrates hold on to water which can increase your weight but give you an extra edge when racing 26.2. Each gram of glycogen holds 3 grams of water (Fernandez).
- Eat every 3-4 hours to keep glycogen stores stocked. Can be small meals throughout the day or three meals plus three snacks. This will encourage tissue repair, maximize muscle strength and top off glycogen stores. Even if your work schedule gets busy, don’t skip lunch or snacks. Snacks are a good way to add in extra carbohydrates without feeling too full.
- Make sure you’re hydrated and drink a glass of water with each meal and throughout the day.
- Opt for lean proteins to provide high quality amino acids. Aim for 20-30 g (3-4 oz) protein per meal. That comes out to about .5-.8 grams protein per pound body weight. Include: grilled chicken, fish, turkey, tofu, egg whites, beans, lentils, and low fat diary.
- Choose low-fat foods to allow for adequate carbohydrates. This will also help from feeling too full. Low-fat foods create space for more carbohydrate-rich foods.Include healthy fats: avocado, nuts, seeds, olive oil, coconut oil.
- Lower your fiber intake so you can accommodate more carbohydrate-rich foods. Eating foods with fiber can make it harder to get the carbohydrates that your body needs.
Race week meal ideas:
Breakfast
Eggs with potatoes and toast
Granola bowl with fruit and yogurt
Smoothie – recipes
Toast with peanut butter and banana
Frozen waffles with fruit and syrup
French toast and side of yogurt
Oatmeal with nut butter and fruit
Baked banana oats with fruit
Toast with avocado and hemp seeds
Cinnamon raisin bagel with almond butter or tofutti cream cheese
Lunch
Wrap with hummus or turkey
Quesadilla topped with avocado
Burrito bowl
Grain bowl from sweet green, ie. harvest bowl
Smoothie and bagel
Pasta salad
Dinner
Grilled salmon or chicken with baked potato + fruit
Sushi
Pasta
Rice and beans
Burrito
Burger (veggie, beef, turkey) on bun with baked potato
Stuffed baked potato (white or sweet) with yogurt
Snack ideas
Bars – cliff, kind, Rx
Toast with peanut butter and banana
Toast with nutella
Crackers with peanut butter
Yogurt with fruit
Tortilla chips with hummus
Rice cake with peanut butter and banana
Trail mix
Fruit or dried fruit
Popcorn
Energy bites – recipes
References
Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. Eur J Appl Physiol. 2015 Sep;115(9):1919-26. doi: 10.1007/s00421-015-3175-z. Epub 2015 Apr 25. PMID: 25911631.
Hawley JA, Schabort EJ, Noakes TD, Dennis SC. Carbohydrate-loading and exercise performance. An update. Sports Med. 1997 Aug;24(2):73-81. doi: 10.2165/00007256-199724020-00001. PMID: 9291549.
Sherman WM, Costill DL, Fink WJ,Miller JM. Effect of exercise-diet manipulation on muscle glycogen and its subsequent utilization during performance. Int J Sports Med 1981;2(2):114-8.
Stellingwerff T, Cox GR. Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations. Appl Physiol Nutr Metab. 2014 Sep;39(9):998-1011. doi: 10.1139/apnm-2014-0027. Epub 2014 Mar 25. PMID: 24951297.
Stellingwerf T. Case study: Nutrition and training periodization in three elite marathon runners. Int J Sport Nutr Exerc Metab. 2012 Oct;22(5):392-400. doi: 10.1123/ijsnem.22.5.392. PMID: 23011657.