5 essential fuel rules for runners

We runners like following the rules. We do as our training schedules dictate, hoping to add precious speed and shave precious seconds. We replace our shoes every 500 miles, hoping to avoid injury. But in a sport that attracts its
share of control freaks (or does it just send us that way?), we often fail to control one of the most important factors in determining our performance – what we put in our mouths. 

Proper nutrition and hydration are critical components of better running. However, many of us are still either playing the fuelling game by an antiquated rulebook – one that prescribes little more than giant plates of pasta and gallons of neon-hued sports drinks – or chasing after the latest fads, such as eliminating gluten. And while many of these strategies may have their place in the runner’s diet, there’s a lot more to consider than carbohydrates, electrolytes and superfoods when it comes to fuelling the successful endurance athlete.

‘Runners often don’t pay attention to the quality and nutrient density of their food – they’re lean, so they think they can eat whatever they want,’ says Jay Sutliffe, associate clinical professor of health sciences at Northern Arizona University, US, and nutrition advisor to the university’s running teams.

When it comes down to it, top distance runners don’t fall for the fads; they get the basics right, eating whole, quality foods, including grains, fruits, vegetables and lean protein. From these they get all those micronutrients that speed recovery and replenish your energy stores, allowing the body to adapt to training and, ultimately, perform better.

In the spirit of keeping things simple, we’ve scoured the research and quizzed the experts to narrow your nutritional strategy down to five basic commandments that will give your body what it needs to run better.

1. Eat carbs and choose them wisely 

While the scientists carry on trying to work out whether endurance athletes can teach their bodies to oxidise more fat as fuel, the truth remains that carbohydrates, stored as glycogen, are the best and most readily available 
form of energy for muscle strength and endurance – and runners need carbohydrates to perform and recover.

How much of your diet to devote to carbohydrates depends on you, and where you are in your training cycle. For somebody who is in a low- or moderate-mileage phase, nutritionists prescribe three grams per kilogram of body weight. As your training volume increases, increase that to five or six grams per kilogram of body weight per day.

The trick, though, is to choose the form of those carbohydrates well. Carbs have had a bad press over the years because most people associated them with white breads, pasta and refined grains – many of which also contain refined sugars and/or saturated fat. But fruits and vegetables, as well as wholegrains, also count as carbs, and those are the kind runners should gravitate toward.

‘You can pick a piece of fruit or you can pick a box of crackers,’ says Stephanie Howe, an elite ultra runner who is also working on her doctorate in nutrition and sports science. ‘The carb content may look the same, but the apple is also going to give you essential vitamins and minerals.’

As for pre-race carb-loading, it really only helps for those who are running marathons or ultra distances, and even then it doesn’t mean you should inhale a giant plate of penne 12 hours before the race. Instead, nutritionists advise increasing intake beginning three or four days before the race by adding a few more carbohydrates to each meal.

‘Most people already have enough glycogen storage for 20 miles of running,’ says elite trail runner Alicia Shay, nutrition advisor at the Hypo2 High Performance Sport Center. ‘If you eat a huge load of pasta the night before the race, it can lead to gastric distress, and it’s not going to be readily available. Just add small amounts of carbs throughout the day so you can digest it.’

When it’s race time, switch to a different kind of carb to sidestep the dreaded ‘wall’. Trent Stellingwerff, innovation and research physiology lead at the Canadian Sport Institute, advises feeding the body easily digested carbohydrates such as gels and sports drinks during racing or prolonged exercise. ‘Simple sugars like sucrose and fructose are the way to go,’ he says.

And how about the increasingly popular tactic of ‘fasted training’ (deliberately running with depleted carb stores to force your body to adapt and burn more fat as fuel)? The scientific jury is still out, but many experts don’t recommend it except as a last resort in the training arsenal – most runners could see performance improvement by adding other simple stresses for the body to adapt to, like increasing mileage, instead of toying with fuel depletion.

If you do decide to give depletion a try, Kyle Pfaffenbach, nutrition consultant for the professional Brooks Beasts team, emphasises what many of the experts say: there is a safe time to do this in the training cycle – and it is early. Depletion runs take a toll that athletes can’t recover from fast enough during high-intensity periods or close to race day.

Bottom line 

Runners need carbohydrates, but should be careful in choosing the healthiest versions and not overdoing their intake. Science does not yet fully support the notion that most runners will benefit from depletion runs, but those who try them should pick a safe time in the training cycle to allow proper recovery.

2. The recovery window 

Coaches and sports nutritionists have been harping on about it for years, but does the 30- to 90-minute eating window to maximise recovery genuinely exist? Well, it does if you want your body to quickly absorb and use nutrients to repair muscles and replenish your fuel stores. Nutritionists are still pushing a 3-4g:1g carb-to-protein ratio when possible, but say that it’s really only needed after prolonged or intense efforts. In research on recovery nutrition that Howe is currently conducting, she’s finding that the ratio – consumed to the tune of about 250kcals – will help replenish what a runner has lost, but it may not be as important as merely eating something. And while many recovery food fads come and go, nobody has yet found a mystical perfect source of recovery fuel. ‘Usually your appetite is suppressed after a race or a training session, so I say that anything you can get down is good, whether it’s a sports drink, a bar or a peanut butter sandwich,’ says Howe. ‘There’s no magic superfood out there. There are a variety of foods that will get you the nutrients you need.’

Pfaffenbach encourages the Brooks Beast team to try to get post-workout fuel from liquid sources, so that it is quickly absorbed into their systems. He also downplays the current hype about chocolate milk, pointing out that it contains fat that will slow the absorption process. 

‘There’s no lack of products out there that have everything you need in a recovery drink,’ Pfaffenbach says.
‘I recommend checking the ingredients lists for additives – or making your own with organic options, like smoothies
with fruits high in simple sugars; carbs; and add some whey protein.’ He advises measuring out a post-run recovery smoothie that has 8-10g of whey protein and 32-40g of carbohydrate.

Bottom line 

After hard training and racing efforts, jump-start the recovery process by eating or drinking 200-300kcals of 3-4g:1g of carb to protein, up to 90 minutes post-exercise. Choose whole foods when possible.

3. Eat real food

Although the sports nutrition experts don’t agree on everything, there’s one piece of diet advice they prescribe time and again: eat more fruit and vegetables, every single day.

‘We spend a lot of time talking about ratios – runners have basic needs for calories and fluids, but how you get those calories makes a huge difference,’ says Sutliffe. ‘Typically, we see a lack of micronutrients in the diet that provide the vitamins, minerals, antioxidants and coenzymes to help build the mitochondria.’

We need to feed those mitochondria because they are the little cellular powerhouses that generate energy to be used by the muscles, nerves and heart. So where do those micronutrients come from? Think green – foods like kale and spinach, which are the most nutrient-dense foods and are full of what endurance athletes need: vitamins K, A and C, magnesium (helps reduce muscle cramps) and flavonoid antioxidants (anti-inflammatory).

‘The best-performing runners’ diets include fresh, unprocessed food, quality protein and lots of fruits and veggies,’
says Sutliffe. ‘It’s so simple and so overlooked by many runners – I am a big believer that the food you’re eating for every meal and snack is critical to adapting to training stress.’

Shay subscribes to food author Michael Pollan’s mantra: ‘Eat food. Mostly plants. Not too much.’ Athletes at the highest levels have well-balanced diets that aren’t extreme one way or the other, she says.Bottom line 

Bottom line

Fuel performance by focusing on quality foods, including lean protein (fish, eggs, poultry), wholegrains (brown rice, barley, quinoa, whole oats), legumes (beans, lentils), fruits, vegetables and healthy fats (nuts, avocados, seeds, oily fish).

4. Take it easy with electrolytes 

The sports industry has done a great job of convincing us that we need electrolytes to perform better. And we do – just not as much as we think. ‘There’s a lot of marketing going into the importance of electrolytes, and it’s sometimes overstated,’ says Pfaffenbach.

The biggest concern about the loss of electrolytes – sodium, potassium, magnesium and calcium – comes when you’re training or racing for two to three hours or more. When running for that long and losing electrolytes through sweat, there is certainly a need to replace them with gels or sports drinks. Nutritionists recommend 0.5-0.7g of sodium per litre of fluids.

‘It’s almost the same as your thirst mechanism. Your body tells you when it’s thirsty,’ says Shay. ‘If you’re craving salt, you need it – but don’t take it blindly.’

As for hydration, the advice is still pretty basic. In terms of post-run rehydration, Stellingwerff suggests conducting the old sweat test to work out how much fluid you’re losing. One litre of sweat equals one kilogram of body-weight loss. If you don’t drink anything, then exercise for one hour and lose a kilogram, your sweat rate is a litre per hour. And how much should you drink during a race? Even simpler: drink when you feel you need to.

Bottom line

Electrolyte replacement is most important for long efforts and/or particularly warm weather. However, don’t take in electrolytes blindly – keep tabs on how much you’re ingesting.

5. Elimination diets wont improve your performance 

Spend an afternoon reading a variety of runners’ blogs out there and you’ll find that the ‘secret’ to success is obviously eliminating wheat, barley, rye, grains, legumes, dairy, salt, oils… the list goes on. More commonly known by labels such as ‘gluten-free’ and ‘Paleo’ diets; their advocates say that ridding themselves of one food group or another has propelled them to running greatness.

‘It’s a huge pet peeve of mine,’ says Shay. ‘People read this stuff, replicate it and think it’s somehow scientifically proven to help them run better. But it’s not rooted in evidence.’

With the exception of coeliac disease and diagnosed food allergies, there’s little science backing claims that cutting
gluten or following a diet that prescribes an overabundance of fat and protein will help performance – in fact, because science has proven that endurance athletes need carbs, overdoing the fat and protein just may hinder it.

One potential upside is that these diets may force a runner to cut down on foods such as biscuits and crisps, says Howe. ‘For those who don't have coeliac disease or allergies and still claim to feel better after eliminating gluten, it’s probably because they’re eating.

Bottom line 

Science doesn’t support the claim that eliminating food groups can boost running performance, unless a runner has diagnosed allergies.