What should I eat when training for a marathon?

Which foods best fuel a daily training regime? Marathon runner Alice gets advice from a nutritional therapist and reveals the effect of dietary changes.

Legs of runners in action

I’m a keen runner and recently completed my first marathon. While I was really happy with my time, the lead-up to the race was tough, in large part because of my diet. I trained about five to six times a week, running between 7-10 miles most days and 20 miles on Sundays. As a result, I was constantly ravenous. I’m a self-confessed sugar addict and tended to stave off hunger quickly by binging on chocolate, cookies or the odd jar of Nutella, especially in the evening. Frankly, I convinced myself I’d earned it! Unfortunately, all that excess sugar just made me gain weight and feel lethargic. In a bid to shed pounds before the race, I lived off salad leaves, which was miserable and wreaked havoc on my muscles.

With the Virgin Money London Marathon in my sights this April, I decided I needed expert help, so I turned to a nutritional therapist…

What to eat when training for a marathon

When I filled out a food diary and health questionnaire, then met with our nutritional therapist, she advised that my current diet was lacking enough protein and healthy fats to fuel my body sufficiently. This explained why my legs would never recover from one run to the next. Nicola recommended two simple but key things I should do in the coming weeks:

Refuel by eating breakfast

Bowl of porridge oats and milk with chopped banana and blueberries

I normally skip breakfast, so the first change Nicola recommended was to start eating a small bowl of porridge each day after getting back from a run to restock muscle glycogen.

Nicola’s advice: “Alice usually ran first thing in the morning and would grab a banana once she got to work a few hours later. Whether you're hungry or not, the quicker you consume food after a run the quicker the body can recover and restore the lost glycogen, which is a bit like filling your car up with petrol after it has run empty. However, a banana is not enough for a post-run breakfast, especially in marathon training, so Alice was finding she was often exhausted for the rest of the day and struggled to concentrate. She was also running the risk of injury or illness by restricting her diet so much.”

Repair by eating protein

Black-eyed bean mole and vegetable salsa in a bowl

Nicola added that I needed to eat more lean protein (chicken, turkey, eggs, fish, lentils, chickpeas, natural yogurt) to help maintain and build muscle and keep me fuller for longer. She explained that the sugar cravings were due to my body signalling that it needed more energy and sought the fastest route to getting this, and it was important to balance portions to avoid those cravings. I was also surprised to hear that although carbs such as potatoes and rice are important in providing a ready-available fuel source, they should not form a large part of our diet. Nicola showed me a pie chart with proportions of each food group. Leafy greens, non-starchy vegetables or salad formed about half, protein a quarter, with the last quarter reserved for carbs, rounded out by some good fats.

Read more on pre and post-run fuelling:

What to eat before your run
What to eat to recover from your run
Nutrition for runners infographic

Diet preparation

Assortment of shopping groceries

The prescribed diet consisted of a lot more beans, pulses and root vegetables than I would normally eat, so for once, I felt rather virtuous about my shopping basket. With lots of vegetables and cans to buy, my cupboards and fridge seemed to overflow, but this allowed me to properly stock up for the week and batch cook for busy nights ahead. I aimed to make casseroles for dinner, and whip up salads or homemade soups for lunch to help me reduce my sugar intake (avoiding hidden sugar in shop-bought soups and sandwiches). Coincidently, we had recently tested soup makers in the Good Food test kitchen so I borrowed one and was set to get blending.

Week 1 – bridging the hunger gap

I ate a small bowl of porridge or muesli in the morning after coming back from a run, topped with antioxidant-rich blueberries, cinnamon, chopped bananas, or a drizzle of honey. This helped noticeably in restoring my energy levels after a long run and kept my sugar cravings at bay. I didn’t often feel I wanted to eat straight after training, but by mid-morning I’d feel hungry, so Nicola advised snacking on a few almonds alongside my normal banana, which helped bridge the gap until lunch and slowed the release of the sugar in the fruit.

Find out how to reduce sugar in your diet.

Week 2 – meal prep and cooking from scratch

Bowl of courgette and tomato salad topped with sliced halloumi cheese

By the second week, I was getting used to cooking from scratch, rather than relying on my normal go-to pasta and pesto. The only struggle was the increased prep time and initially it felt like I’d be chopping vegetables until the end of time. Surprisingly, I got quicker (or at least, I got used to it) and I started to appreciate knowing exactly what was in my food and therefore, what I was putting into my body. My new favourite recipe became spicy root & lentil casserole. This took about an hour to make but I prepared a large enough batch for four extra portions, which I froze in food bags. Following a long run, I also enjoyed a healthy and flavoursome portion of Mexican penne & avocado – an ideal way to refuel whilst packing in all five of my five-a-day.

Penne in tomato sauce topped with avocado on a plate

My lunches alternated between salads and soups. One of my favourites was a butter bean & tomato salad that I topped with some delicious grilled halloumi. Avocado and smoked salmon salads were also great for work as they supplied the much-needed healthy fats. The soup maker got a fair old workout and my go-to soups became carrot & coriander and courgette, pea & pesto soup. (If you haven’t splashed out on a soup maker, a hand blender will also do the trick.)

Discover more marathon recipes:

Marathon recipe collection
Marathon meal plans

Bowl of soup with whole peas, canellini beans, peas and courgette

Nicola’s advice: “Foods such as beans and lentils are an excellent combination of protein, carbs and fibre, which provide a sustained release of energy so Alice could stay fuller for longer, whilst allowing her to maintain her marathon weight without going hungry or having sugar (or energy) cravings. The key is balancing the food groups and not just falling into the trap of ‘carbing up’ during training as the body will soon burn through this. The muscles need protein and fats, too.”

I was well acquainted with the feeling of ‘hitting a wall’ when, after running for over 75 minutes, your legs start to feel like lead and all your energy has gone. To deal with this a lot of runners take energy gels and sports drinks every 45 to 60 minutes to top up ready available carb stores, although these unfortunately make me feel queasy! I’d always been good at rehydrating straight after training but hadn’t realised it was just as important to consume a protein and carb-rich snack within 30 minutes after a run, to prevent the breakdown of muscle.

Butterbean and tomato salad in a wide bowl

Nicola’s advice: “During a marathon the body will need some fast-burning carbohydrates to provide fuel for your muscles and consuming a piece of fruit with some nuts isn’t always practical! Plain water isn’t enough though, so making your own sports drink with diluted fruit juice and some added salt is a great option. If you are able to run with food, then raisins or pretzels are a good choice, or some runners turn to jelly babies or jelly beans as a sweet hit that are easy to carry and the body can use as fuel quickly.”

Find out more about what to eat and drink on long runs:

What to eat when running a marathon
What to eat on heavy training days
How to stay hydrated when training for a marathon

Week 3 – finding the balance

Assortment of fruits with matcha yogurt in a bowl

I must admit, trying to avoid sugary snacks whilst working in an office where there is a seemingly endless supply was a challenge, so I did allow myself a few treats. However, I would limit them to the day, satisfying my sweet tooth with fruit salad or herbal tea in the evenings. This was a tough habit to break at first, but eating more substantial main meals with chickpeas, lentils and beans left me feeling fuller with less need for pudding.

I also found that getting up in the morning to train was a lot easier having not overloaded on chocolate the night before. Importantly, Nicola helped me realise we can’t always be perfect and the restrictive notion of ‘clean eating’ is often counterproductive. Unless, there is a medical reason to do so, depriving ourselves of whole food groups often sets us up to fall off the bandwagon and descend back into a cycle of binging.

The results

On my final meeting with Nicola, I filled out the same questionnaire as before and was massively relieved to find my list of health niggles had decreased substantially with just a few simple dietary changes. Eating a more balanced and sensible diet throughout the day has kept my energy levels sustained and improved my focus, as well as reducing energy dips during training. It has also helped my muscle recovery immensely and I look forward to seeing how this affects my next race.

Overall, this experience has helped me discover just how powerful food really is in affecting how our body functions. I am definitely going to carry on eating this way, and will try to cut back on sugar a bit more but I’ve realised it comes down to finding that balance between giving your body the fuel it needs and not getting obsessive about what you eat at the same time. Easier said than done but, like running a marathon, anything is achievable if you put in the hours and want it enough. So, for anyone thinking of entering a race, whatever the distance – just go for it, you won’t regret it!

Picture of a Alice in a tracksuit top with a medal

Nicola’s advice: “When I first met Alice she was literally ‘running on empty’. So keen to achieve a good marathon time and yet her body just wasn’t getting enough fuel to carry her through her training, or her day for that matter. By increasing the amount she ate, but with the right foods, Alice had much more energy without the weight gain, and we were able to prevent any injury or illness at the same time.”

Read more about maintaining a healthy weight while training:

Fitness and fat burning
How many calories will I burn from running?
Exercise tips for weight loss

Find more dietary advice for running a marathon...

Marathon training and nutrition hub
Paul Radcliffe: How to run your best marathon
Michel Roux Jr: How to run a marathon
Your marathon questions answered
8 things I wish I'd known before running a marathon
Carb loading explained

Do you have any dietary tips for marathon training? Leave a comment below...

Nicola Shubrook is a qualified nutritional therapist, working with both private clients and the corporate sector. She is an accredited member of the British Association for Applied Nutrition and Nutritional Therapy (BANT) and the Complementary & Natural Healthcare Council (CNHC). Find out more at urbanwellness.co.uk.

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