There's a moment every autumn when the training suddenly feels harder to protect. The clocks are about to go back, the weather turns, half the office has a cold, and one badly-timed bug can wipe out a fortnight of hard-won fitness right when you're building towards a goal.
Nothing derails a training block quite like being ill. And while you can't bubble-wrap yourself against every sniffle doing the rounds, what you eat through the darker months has a real, measurable influence on how well your immune system copes. The good news is that autumn also happens to serve up some of the best immune-supporting food of the entire year - if you know what to reach for.
Here's how to eat for the season, stay well, and keep your training ticking over towards events like the Christmas Chilly 10k.
Why runners need to pay attention
Here's something that surprises people: hard training temporarily suppresses your immune system. After a long or intense session, there's a window - sometimes called the "open window" - where your body is more vulnerable to picking something up. Combine that with the general germ-fest of autumn and winter, plus the extra stress of colder, darker training, and you can see why runners often seem to catch more than their fair share.
That's not a reason to train less. It's a reason to support your body properly - and the kitchen is where a lot of that support happens. Consistent, decent nutrition won't make you invincible, but it stacks the odds firmly in your favour.
Eat the seasons - autumn is on your side
One of the simplest rules of good eating is to lean into what's in season, and autumn in the UK is genuinely brilliant for it. Seasonal produce is fresher, cheaper, and often more nutrient-dense - and it just happens to be full of exactly what your immune system is after.
Get these on your plate through the coming weeks:
- Squash and pumpkin - loaded with beta-carotene, which your body converts to immune-supporting vitamin A. Roast a big tray and use it all week.
- Brassicas - kale, cabbage, Brussels sprouts, broccoli and cauliflower are packed with vitamin C and a whole host of other useful compounds. Don't boil the life out of them; roast or lightly steam to keep the good stuff intact.
- Root veg - carrots, beetroot, parsnips and sweet potatoes. Brilliant slow-release carbohydrate for fuelling runs, and great for a warming traybake.
- Apples and pears - in peak British season, an easy portable snack, and a good source of fibre and polyphenols.
- Leeks, onions and garlic - the base of half the good soups you'll make this season, and genuinely useful for gut and immune health.
Notice a theme? These are the exact ingredients that go into the big, warming, one-pot meals we all naturally crave when it turns cold. Your cravings and your immune system are, conveniently, pointing in the same direction.
The nutrients that matter most
You don't need a cupboard full of supplements. Focus on getting these through real food first.
Vitamin C. The classic, and for good reason - it supports immune function and you use more of it under physical stress. Peppers, brassicas, citrus and berries all deliver. Aim for a bit at most meals rather than one big hit.
Zinc. Quietly one of the most important minerals for immune defence. Find it in lean meat, shellfish, pumpkin seeds, chickpeas and lentils.
Polyphenols and colour. The rule of thumb "eat the rainbow" isn't just a slogan - the pigments that make fruit and veg colourful are often the very antioxidant compounds that help your body handle the oxidative stress of hard training. A varied, colourful plate is doing more work than it looks.
Gut health. A big chunk of your immune system lives in your gut, so feeding it well pays off. Fibre from wholegrains, beans, pulses and veg keeps things happy, and fermented foods like live yoghurt, kefir and sauerkraut add beneficial bacteria into the mix.
The one to watch: vitamin D
This deserves its own paragraph because it's the big seasonal gap for anyone in the UK. From about October to March, the sunlight here simply isn't strong enough for your skin to make vitamin D - and vitamin D plays a genuine role in immune function. Food sources like oily fish, eggs and fortified foods help, but they rarely cover it entirely over winter.
The official UK advice is that most people should consider a daily vitamin D supplement through the autumn and winter months. It's a small, cheap, sensible bit of insurance for any runner training through the dark half of the year. If you're unsure what's right for you, have a quick word with your GP or pharmacist.
Don't forget to fuel and hydrate
Two easy things that slip in cold weather.
Keep fuelling your runs. It's tempting to under-eat when you're trying to stay lean over winter, but chronically under-fuelling is one of the fastest ways to run your immune system down and invite illness in. Match your intake to your training - your body needs the resources to both perform and defend itself.
Keep drinking. You sweat less in the cold and feel less thirsty, so it's genuinely easy to end up mildly dehydrated without realising. Warm drinks count, and a good soup does double duty - hydration and immune-friendly veg in one bowl. Speaking of which, a big batch of vegetable soup might be the single most autumn-appropriate thing a runner can make: cheap, warming, freezable, and quietly excellent for you.
Consistency is the whole game
None of this is about eating perfectly. It's about giving yourself the best possible chance of staying healthy, staying consistent, and stringing together the weeks of training that actually add up to a result.
Because that's what a good autumn build is - not one heroic session, but a long run of ordinary healthy ones, uninterrupted by avoidable illness. Eat the season, look after your gut, sort your vitamin D, keep fuelling, and you'll give yourself the best shot at arriving at the start line fit, well, and ready to run.
We'll see you at Castle Combe. Enter the Christmas Chilly 10k & ChrisMax Mile here.
This article is general guidance for healthy runners, not medical advice. If you have a health condition or specific dietary needs, check with your GP or a registered dietitian before making changes.
