What should I eat the morning of a marathon for a sub-3 effort?

It’s always fascinating staying in a hotel packed with marathon runners before a big race. You’ll often see signs at reception announcing that breakfast will be served early - usually from 6am - after dozens of athletes have persuaded the staff to make an exception to their usual Sunday routine. And come race morning, the dining area is full of kitted-up runners quietly going about their rituals: spreading jam, downing coffee, or hunched over bowls of porridge in silent concentration - or chatting away with nervous energy.

Some choices still surprise me. I’ve seen runners in Alphaflys piling up full English breakfasts - sausages, bacon, scrambled eggs - as if it’s the morning after a pub crawl. Others take the opposite approach, bringing their own food to the table: rice cakes, overnight oats, or even baby food sachets. I’m somewhere in between. I bring my own beetroot juice, peanut butter and bagels, but I’ll toast them there and maybe use a bit of the hotel’s jam.

Everyone has their own routine. And if you’re a seasoned sub-3 marathoner, you’ve probably figured out what works for you. Still, it’s worth sense-checking against what the science says. The research is actually pretty clear.

Five Key Principles

1. Prioritise simple carbs
The goal of your pre-race breakfast is to top up liver glycogen, which can fall overnight, and provide readily available energy to complement what’s already stored in your muscles from the previous days of carb loading. Go for refined, easily digested carbs - white bread, white bagels, pancakes with syrup, jam or even plain white rice. Aiming for around 1–1.5g of carbohydrate per kg of body weight two to three hours before the race is a good rule of thumb. For a 75kg runner, that’s about 80–110g of carbs - roughly equivalent to two bagels with jam or a couple of slices of white toast with honey and a banana.

2. Avoid fat and greasy foods
Fat slows digestion and won’t help your performance on the day. That means skipping the bacon, sausages, fried eggs and buttery pastries, tempting though they might be. Your body won’t be using fat for fuel in the early glycogen-rich stages of a sub-3 effort and you don’t want a sluggish stomach interfering with your race.

3. Go easy on fibre
Normally I eat wholewheat bread or bagels, but on race morning I switch to white. The same goes for fruit - on most days I love an apple or berries, but before a race I steer clear. A banana at best. Fibre can stimulate bowel movements at exactly the wrong moment, and you don’t want to be relying on finding a portaloo at mile four.

4. Eat your last solid meal two to three hours before your own start time
This is crucial. Don’t just look at when the elites start - major marathons often have staggered waves, and your own start could be 30–60 minutes later. Set an alarm and time your breakfast accordingly. That gives your body time to digest, absorb nutrients and settle.

5. Sip carbs in the final two hours
After your main breakfast, switch to lighter forms of energy. For me, that’s usually orange Lucozade Sport, a Voom Pocket Rocket and a caffeine gel about 15 minutes before the gun. These top up blood glucose without overwhelming your gut. Just avoid anything heavy or unfamiliar.

Sample Race Morning Meal Ideas

Here are a few combinations that fit the bill for a sub-3 runner:

• 2 white bagels with jam + 1 banana + 500ml sports drink
• 2 slices white toast with honey + small bowl of white rice + beetroot juice shot
• Large plain bagel with peanut butter + low-fibre energy bar (e.g. Clif Bloks or Voom) + tea or black coffee
• White rice with a drizzle of soy sauce or maple syrup + 1 rice cake + electrolyte drink
• Porridge made with water or skimmed milk and a spoon of sugar or syrup (if you know it sits well)

Just Don’t Improvise on Race Day

This isn’t the time for adventure. No matter how appealing the breakfast buffet looks - don’t be tempted by the pain au chocolat, tropical fruit salad or some intriguing local delicacy. You’re not here to get your money’s worth from the buffet. You’re here to fuel for performance.

Stick to what you’ve tested. If you haven’t eaten it on a long run, don’t risk it on race day. Even small changes - like switching from peanut butter to hotel jam, or from bagels to croissants - can unsettle your stomach when your nerves are heightened and your digestive system is more sensitive than usual.

Your race-day breakfast isn’t an indulgence. It’s a strategic, functional meal designed to maximise your chances of running sub-3. Save the experimenting - and the feasting - for after the finish line.