Marathon Nutrition: Setting Yourself Up for Success
As we move into the early months of the year, many runners across the UK are lacing up their trainers and kicking off marathon training plans in preparation for spring races such as the London Marathon. Whether you’re chasing a new personal best, aiming to break a milestone like the 3-hour barrier, or simply determined to complete the 26.2 miles feeling strong, how you fuel your training will be one of the biggest factors in your success.
Nutrition not only influences performance but can also determine how enjoyable the experience is — and even impact your health during and after the event. The right fuelling and hydration strategies can mean the difference between hitting your target pace and “hitting the wall.”
Training Plan
A well-structured training plan is the foundation of marathon preparation. Most marathon programs span around 16 weeks and combine long runs, tempo sessions, and recovery runs to progressively build endurance and speed.
Following a plan tailored to your fitness level and goals can help maintain consistency and reduce cognitive load — each day’s session is planned so you can focus solely on execution and recovery rather than decision-making fatigue.
Get the Right Shoe
Running is a relatively minimalist sport when it comes to kit, but footwear choice has a huge impact on comfort and injury prevention. A gait analysis with a qualified podiatrist or specialist running store can help you select the right shoe for your biomechanics and training volume. Investing in proper footwear early on will pay dividends during higher mileage phases.
Nutrition: Fuel for the Work Required
A personalised, periodised nutrition plan should complement your training schedule. Matching your carbohydrate intake to your training load — often referred to as fuel for the work required — helps optimise training adaptations and recovery.
Lower training days: Lower carbohydrate, balanced meals to support recovery.
High training days: Increased carbohydrate intake to support energy demands and glycogen replenishment.
Guidelines suggest carbohydrate intakes of roughly 5–7 g/kg body weight for moderate training and 7–10 g/kg for heavy endurance training, depending on energy expenditure and goals (Burke et al., 2011). Protein intake of 1.6–2.0 g/kg per day further supports muscle repair and adaptation.
Avoid deliberate weight loss during training. While it might be tempting to try to get lighter to run faster over longer distances, restricting energy intake can hinder your progress more than it helps. Insufficient fuelling compromises recovery, increases injury risk, and limits the body’s ability to adapt to training stress. Rather than chasing weight loss, focus on performance-based nutrition: eating enough to support energy needs, muscle repair, and consistent quality training. Over the course of your programme, body composition may naturally adjust as fitness improves and mileage accumulates.
Carbohydrate Loading
Carbohydrate loading is a science-backed strategy to maximise muscle glycogen stores before race day — your body’s primary energy source during prolonged endurance exercise.
Glycogen stores are limited, with approximately 500 g stored in muscle and 100 g in the liver. Once depleted, fatigue and a sharp drop in pace occur — the dreaded “wall.”
To mitigate this, aim for 10–12 g of carbohydrate per kg body weight for 36–48 hours before race day (Jeukendrup, 2017). This can include familiar, easily digestible foods such as rice, pasta, potatoes, oats, and sports drinks. Adequate hydration and sodium intake should also accompany carb loading to support glycogen uptake and fluid balance.
Race Day Nutrition
Your race-day fuelling plan can make or break your performance. The goal is to maintain energy levels and avoid gastrointestinal distress — and that means nothing new on race day!
Trial your race nutrition during longer training runs to determine which gels, drinks, or foods work best for you. Most runners benefit from 30–60 g of carbohydrate per hour for events lasting 2–3 hours, increasing up to 90 g/hour for elite or longer-duration runners using dual carbohydrate blends (glucose + fructose) (Burke et al., 2011; Jeukendrup, 2014).
Hydration should also be individualised. Weighing yourself before and after key training runs can help estimate sweat losses. The aim is to avoid both dehydration and overhydration by drinking to thirst and replacing lost sodium as needed.
The Bottom Line
Now is the time to align your nutrition strategy with your training plan. Investing time in fuelling practices early in your programme will help you arrive on the start line with confidence — physically prepared, nutritionally ready, and mentally focused to perform your best.
If you’d like guidance developing a personalised nutrition plan to support your marathon build-up and race-day strategy, please get in touch.
References
Burke, L. M., Hawley, J. A., Wong, S. H., & Jeukendrup, A. E. (2011). Carbohydrates for training and competition. Journal of Sports Sciences, 29(S1), S17–S27.
Jeukendrup, A. E. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(S1), S25–S33.
Jeukendrup, A. E. (2017). Training the gut for athletes. Sports Medicine, 47(S1), 101–110.
