7 Marathon Nutrition
Tips For Race Week

Daniel Murphy // Dietitian // Nov 23

Nutritionist running a marathon

Where To Start, Marathon Nutrition

Are you planning on running Cork marathon or Dublin marathon this year? Marathon week is a crucial time for runners as they gear up for the big race day. Proper nutrition during this period can make a significant difference in performance, energy levels, and recovery. In this section, we’ll explore the first set of 7 marathon nutrition tips for race week. These tips will help you get your body in top condition for the race.

Setting the Stage for Marathon Success

The Final Countdown

Race week is when all the hard work you’ve put into your training starts to culminate. It’s crucial to treat your body right as you approach the big day. Nutrition plays a pivotal role in setting the stage for marathon success. Nerves will always play a part but with an effectively practiced nutrition strategy, food is one last thing to worry about.

Sport nutritionist running a marathon

1. Hydrate, Hydrate, Hydrate

One of the most fundamental aspects of marathon nutrition during race week is hydration. Staying well-hydrated is key to optimal performance and recovery. Dehydration can lead to cramps, fatigue, and poor race-day performance. Even mild dehydration around 2% losses can significantly impair endurance performance by up to 20%. Going past 2% water losses could possibly mean your race day is over. This is especially important for Cork marathon as the June Bank Holiday weekend can be warm. An ice slushy can reduce your core body temperature and be the perfect solution to a run on a warm day. 

Baseline water requirements start at 35ml per kg of bodyweight. This can vary drastically on training volume and sweat rates. 

2. Carb Loading

Carbohydrates are the primary source of energy for marathon runners. During race week, you should gradually increase your carbohydrate intake to ensure your glycogen stores are fully topped up. Carb loading is a process of increasing carbs 24-36 hours before the day of the race to provide up 25% increase in energy on the day of the marathon. This can be a difficult process on your own so make sure to get guidance from a sports nutritionist before attempting it. 

During this period Carbs can increase to 8-12g per kg of bodyweight. For an 80kg person this can mean 800g of carbs over a 36 hour period. If done correctly, carb loading will fuel you for a large portion of the marathon. The main tip is to focus on low fibre carbs such as cereals, juices and syrups. Also lessening high fibre foods such as vegetables and wholegrain products as these can cause stomach cramps when loading. 

3. Carbohydrates and Fuelling

One of the key strategies to prevent hitting the wall is proper pacing and fueling. Start the race at a manageable pace, and consume carbohydrates regularly to ensure a steady supply of energy. Energy gels or chews can be particularly helpful in this regard. Aim for 60-70g of carbohydrate every hour. Take note of gel and sport drink spots on the course and calculate based off your expected finish time how much carbohydrates you’ll need. 

For example: 60g of Carbs x 3 hours = 180g of carbs over the duration of the race. 5 gels x 1 litre of sports drink over the duration. This is in an ideal world but strategy may go differently on the day. 

4. Protein for Recovery

Protein plays a crucial role in muscle repair and recovery. While carbohydrates take the lead in providing energy, proteins help repair and rebuild muscle tissues that inevitably experience some damage during long runs.

Aim to consume about 15-20% of your daily calories from protein sources like lean meat, fish, beans, and dairy products. This can help with muscle recovery and prevent muscle breakdown, especially if you’re doing strenuous training sessions during race week. Many athletes overdo it with protein. 

Protein is a poor energy source. Aim for 1.7g per Kg of bodyweight. This is enough to promote recovery and allows more room for added carbs.

5. Supplements for Marathons

While a well-balanced diet should provide most of the essential nutrients you need, some marathon runners may benefit from vitamin and mineral supplements. Iron, calcium, and vitamin D are often of concern for endurance athletes, as deficiencies can affect performance and overall health.

Gels: An excellent way of fuelling while running. Find a brand that suits you and stick with it. Be sure to check what gels are available on race day so that new foods are not introduced on the big day.

Beetroot Juice: Taking 1 shot of beetroot juice a day on the 2-3 weeks lead up to the marathon has a vasodilation effect. What does this mean? Beet juice contains concentrations of nitrates which expand blood vessels. In turn, more oxygen is delivered to our muscle allowing us to go for longer. 

Beta Alanine: This supplement works as a lactate buffer. As lactic acid builds up in our muscles, causing pain and soreness. Beta Alanine works by increasing carnosine levels in the body. Reduced lactic acid build up allows us to run for longer distances.

Supplements are a great addition but cannot correct poor fuelling and an incorrect diet. Always look to start with a food first approach and get advice on supplements that will help you hit a marathon personal best on the day. 


"Hitting the wall" is a term often used to describe the point during a marathon when a runner's energy levels suddenly plummet, and fatigue sets in. This phenomenon occurs when glycogen stores become depleted, and the body switches to burning fat for fuel. While hitting the wall can be a real challenge for marathon runners, proper nutrition strategies can help you avoid it.

6. Creating a Race Week Meal Plan

The Last Supper

The night before the marathon is often referred to as “The Last Supper.” This meal is crucial, as it provides your body with the necessary fuel to start the race strong. Aim for a balanced meal that includes complex carbohydrates, lean proteins, and healthy fats. Some options could include grilled chicken with quinoa and steamed vegetables or a hearty bowl of pasta with tomato sauce and a side salad.

Avoid heavy, fatty, or overly spicy foods that could lead to discomfort during the race. Stick to foods that are familiar and well-tolerated by your digestive system

Breakfast Of Champions

Race-day breakfast should provide you with a blend of fast-acting and slow-releasing carbohydrates. A good choice could be oatmeal with sliced bananas and a drizzle of honey. Add a source of protein, such as Greek yogurt, to keep you feeling full and satisfied.

Ensure that you eat your pre-race breakfast at least 2-3 hours before the race starts to allow for digestion and prevent any stomach discomfort. It’s also essential to practice your race-day breakfast during your training to ensure it works well for you.

7. Fuelling During the Marathon

Staying hydrated during the marathon is critical to maintain your performance. Dehydration can lead to decreased energy levels and even impair cognitive function. Carry a water bottle or use hydration stations along the course to sip on water at regular intervals.

For longer races, consider using sports drinks that provide both fluids and electrolytes to replenish what you lose through sweat. The amount of fluid you need to consume during the race will vary from person to person and depends on factors like weather conditions, sweat rate, and personal preferences.

Sport nutritionist running the end of a marathon

Success Stories from Apex Nutrition’s Marathon Runners

Marathons are a test of physical endurance, mental resilience, and, of course, the right nutrition strategy. At Apex Nutrition, we’ve been privileged to witness the incredible journeys of our clients who’ve harnessed the power of proper marathon nutrition. Here, we share some inspiring success stories that highlight the significance of tailored nutrition plans and the positive impact they’ve had on marathon performance.

Sub 3 Hour Marathon Success: Sarah

One of the most remarkable success stories comes from Sarah O’Connell, an avid runner and Apex Nutrition client. Prior to seeking our services, Sarah had always struggled with hitting the wall during marathons. Despite dedicated training, she often found herself fatigued and unable to maintain her pace in the latter stages of the race. Sugar cravings were a massive part of Sarah’s week.

After consulting with Apex Nutrition, Sarah received a personalised nutrition plan that included a careful balance of carbohydrates, proteins, and fats. Our expert guidance allowed her to fine-tune her marathon-week nutrition, optimising her hydration strategy, and providing the ideal race-day meal plan.


The results were astounding. In her most recent marathon, Sarah not only avoided hitting the wall but also achieved a personal best time and her goal of a sub 3 hour marathon. With improved energy levels, she maintained a steady pace throughout the race and even had a strong sprint to the finish line. Sarah’s story demonstrates the transformative power of tailored nutrition strategies, and her success serves as a testament to the effectiveness of our approach.

Write Your Story & Reach New Heights

Are you ready to script your own success story in marathon running? Apex Nutrition is here to guide you on your journey to excellence. Our tailored nutrition plans have already transformed the lives of numerous clients, helping them reach new heights in their marathon endeavors. Don’t leave your marathon performance to chance. Take the first step towards realising your potential by reaching out to us today. Click below and schedule a free consultation today. Join the ranks of our successful clients and unleash your full marathon potential with the power of proper nutrition. Your marathon success story begins here.

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