Is Your Food Helping Your Training?

nutrition for running
Good nutrition is a core component for training and performance in sport. But what is “good nutrition” exactly? How do we know if we’re eating well enough? How much should we be eating for training, and when? And if nutritional requirements are different for everyone, how should we go about understanding our own personal needs, and tailoring our diets to best suit our individual requirements?

To dig deeper, we talk with Dr Justin Roberts, a senior lecturer and researcher specialising in nutrition in sport, based at Anglia Ruskin University in Cambridge.


Nutrition can feel like a bit of a minefield. There are so many strong opinions, often totally contradictory. Where do you turn for solid advice?

Sports nutrition specialist Dr Justin Roberts is clear that the best approach is to work out what you—as an individual—need, and what works best for your running. This is not necessarily an easy task, and requires an open mind and a willingness to try different approaches to your diet.

To get started, there are some key questions we can explore around how much, when and what we eat, as well as how we start to identify and plan our personal diets.

How much do you eat?

Are you eating the optimum amount to support your training effort? And how do you know?

Justin explains:

“When I’ve worked with athletes who are training hard, I’ve seen a real variety in terms of how much people eat compared with what they need.

“Some people are just not eating enough to sustain regular training; others have fluctuating low or high days in terms of calorie intake; and others over-eat, or eat at the wrong times of day. So the first place to start is by understanding how much you need.

“If you feel low on energy, get easily tired during training, or don’t recover quickly, it may be that you’re not getting enough good quality nutrition. Are you putting enough in the tank?”

Of course the ‘right amount’ of food needed varies enormously between people, depending on individual characteristics such as weight, training status, and on how much exercise they are doing.

What do you eat?

Energy levels is a topic Justin frequently encounters:

“Runners often ask me ‘How do I improve my energy?’ When people say that to me and I then look at their diet, I often find they are not eating a natural, wholefood diet, it’s more likely to contain on-the-go processed food.

“So they’re not really putting high quality food in that will give them energy for training.”

Justin emphasises that natural, wholefood is healthiest. He thinks most people have a rough idea of what’s “healthy” but have a harder time sticking to that in their diet due to practical logistics and/or busy schedules:

“People get into habits of eating on-the-go processed food. Often it’s because of necessity. Take a look around us here…”

We are sitting in a cafe. There are various vending machines with ready-meals and fizzy drinks, and a cafe bar packed with chocolate bars and crisps.

nutrition for running

Sometimes our food choices are constrained by where we are.

“… There aren’t really any natural foods, everything is in packets and highly processed. To keep those foods stable for longer they usually need preservatives, and contain unnecessary ingredients we just don’t need. They often have higher saturated fat content too. So sometimes it’s hard to make good choices when you are limited because of where you are. We can end up just eating whatever food is available.”

So in an ideal world, what food should we be including in our diets?

“Fundamentally there are some general guidelines that would suit most people.

“Your diet consists of macronutrients and your micronutrients. For the macronutrients, we need a balance of carbohydrates, fats and proteins. But it’s important to make good choices within each of these groups.”

Have a think about the following…

  • Types of carbohydrates: Are you choosing moderate-to-slow releasing carbs, that are relatively low in sugar, and more based on starch and fibre?
  • Types of proteins: Are you choosing proteins that are typically lean (low fat), and coming from a variety of sources? Are you consuming a good balance of protein over the day rather than loading it mainly into one meal?
  • Types of fats: Have you got a good balance between the polyunsaturated, monounsaturated and saturated fats?
    – In analysis of diets, unsaturated fats tend to be underrepresented. For example, there may be a low intake of Omega 3, found in oily fish, nuts, and seeds, and also Omega 6 which is more plant based such as olive oil.
    – Justin advises aiming to minimise saturated fat, keeping it approximately 10% or less of your total calories, and trying to tip the balance in favour of polyunsaturated fats. Saturated fats would be things we tend to consider unhealthy like highly processed foods, cheeses, those types of things.
  • Of course, vegetables and (to a lesser extent) fruit are absolutely essential. They are sources of vitamins and minerals, and runners sometimes have low intakes in some of these such as Vitamin D, magnesium and zinc.

nutrition for running
When do you eat?

“There’s a lot of evidence now that nutrient timing and regularity is just as important as the total amount you eat.” explains Justin.

“Individual people need to work out what works best for them in terms of when they eat – in particular how many meals each day, and how long before or after training.”

He also explains that the timing of meals can affect how the gut functions, for example larger meals may affect GI distress during training. For many people who train hard, it’s better to eat smaller quantities through the day rather than fewer large meals.

Different things will work for different people, so it’s helpful to try things out and see how they suit you. Be open minded.

How should we go about improve our diets?

It seems that a lot of runners are keen to improve their diets. But can be hard to know how to go about doing it, in a way that fits easily into our lives.

Justin’s advice is to think about planning and structure of your diet:

“As an example, when I was doing a lot of training, I would have a weekly plan for my meals. Now I have a three day plan for meals, and I shop for that food. I just rotate those meals, and it simplifies everything. Every meal is different and contains varied ingredients and natural, fresh wholefoods.

“I’ve tried different things, like changing meals every 4 or 5 days, or even every 2 days, but for me personally I find every 3 days is manageable and it works for me. I think that’s really important – people need to find what works for them.”

Personalising your diet

So, applying this in practice, how exactly do you work out what works best for you? How do you personalise and apply the principles?

Justin says:

“Well, to start with, if you have any health issues or underlying symptoms, go and see your GP for guidance. If you do get professional dietary advice, try to follow that one single approach (at least for a period to see if it works for you) – sometimes people try various different things all at the same time, or follow several different pieces of advice at once, which makes it harder to understand the effects.

“You can also ask your GP for a blood screen if you have concerns, which can show up issues such as high cholesterol or low Vitamin D.

“Use evidence-based research rather than myth or invention. Be careful of what you might find from googling!”

And if you don’t have any underlying issues?… Justin advises trying the following approach:

  1.  Set up a spreadsheet with the calories you need per day, with the balance of carbs, proteins and fats you need.
  2. From there, break it down. Think about how many times a day you are going to eat.
  3. Have you got enough fuel before training? (2-3 hours before training)
  4. Are you thinking about recovery intake?

It’s about experimenting and learning. Try to adapt small things first and change a few of your habits if needed. Depending on how good your diet is to start with, it may be that just small tweaks can make a big difference.

So, using the approach above, you can make an actual menu plan of the diet. To do this well here are three top tips:

  1. Enjoy your food: Write down a list of foods you like. Doesn’t have to be entirely boring – you need to like what you’re eating!
  2. Meals with variety: Plan out 3-4 different breakfasts, lunches and dinners. Include a variety of different foods within each meal. If you need help with this, there are various books about nutrition for sport, often including recipes.
  3. Apply common sense: Is it practical? How long does it take to prepare? Find things that work.

And finally… treats are ok!

“I’m a really big believer in giving yourself some time out,” says Justin.

“I tend to suggest keeping this down to one or two meals a week. It’s important to set a good pattern where you don’t feel you depend on treats, but I tend to recommend athletes give themselves a break, and to enjoy a recovery period after a particularly intensive session.

“I’ve also noticed that this stops or reduces cravings. As long as it’s in moderation.”


nutrition for running
Dr Justin Roberts is a senior lecturer and researcher with The Cambridge Centre for Sport and Exercise Sciences at ARU. He is a Registered Nutritional Therapist as well as an accredited Sport and Exercise Physiologist and Chartered Scientist with the British Association of Sport and Exercise Sciences (BASES) and a Member of the American College of Sports Medicine (ACSM).

With over 20 years’ experience in sport and exercise physiology and nutrition, Justin has worked at various institutions including the British Olympic Medical Centre (London). He specialises in performance and functional nutrition with a central aim of exploring dietary and supplementation strategies to support performance, recovery and health-related adaptations to exercise.

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