There's no magic ingredient in a runner's diet - but these tips will help ensure you get the right nutrients at the right time, to fuel your running and recovery.
Know your energy needs
Runners burn an average of 100 calories per mile, so if you are running 20 miles a week, that means you'll need an additional 2000 calories in order to maintain your current weight. Make sure you get the extra energy from healthy sources rather than mindless snacking! If you want to shed a few pounds, only reduce calorie intake a little or you won't have the energy to train.
Carbohydrate is the five star fuel for runners, because it is converted into glycogen, the body's preferred energy source for physical activity. We can only store enough glycogen for 90-120 minutes of strenuous exercise so make sure you regularly include carbohydrate-rich foods in your meals and snacks to keep levels topped up.
Know your GI
Carbohydrates are rated on the ‘Glycaemic Index' (GI) - a measure of how quickly they release sugar into the bloodstream. For good health, aim mostly for low to moderate GI foods (such as brown rice, lentils, wholemeal bread and pasta, porridge oats, beans and pulses. High GI foods (such as white bread and pasta, mashed potato, refined sugar products like jam, sugary drinks, dried fruits) do have a place, however - they are good at providing instant energy and therefore good for replenishing energy after a run.
Be protein savvy
In the throes of their carb obsession, many runners skimp on protein - but being an active person, you actually need slightly more protein than the average couch potato because protein plays a major role in muscle repair and recovery. If you are running regularly, you should aim for 1.2-1.4g of protein per kg of your body weight. Go for healthy, lean meat and fish and low fat dairy products for the majority of your protein sources. Nuts, seeds and pulses are also nutrient-rich options.
Don't run on empty
Running on an empty stomach (before breakfast, for example, or after a long day at the office) can cause low blood sugar (hypoglycaemia), which could leave you feeling tired, dizzy and lightheaded, and will increase your ‘perception of effort', possibly making you go slower or cut your run short. High GI foods can provide readily accessible fuel before a run, or if you don't have time to digest, sip a sports drink.
Drink little and often
Many of us are guilty of only remembering to drink when we're about to go for a run, or when we get back. It's important to stay hydrated throughout the day - not just during and after runs. Even a 2 per cent level of dehydration can affect your performance.
Work out your fluid needs
The American College of Sports Medicine reports that typical sweat rates for a runner can range from 0.4-1.8 litres per hour, so how do you know how much fluid is right for you? It used to be believed that thirst was not a good indicator of hydration status, but experts now believe it is wise to consider how thirsty you are when deciding whether or not to take a drink. Another good indicator is the colour - and volume - of your urine. And use your common sense. If you've been running at a fairly hard pace on a hot day, and have been sweating profusely, you may need to consider drinking a little more than you would on a cool day running at a more leisurely speed.
Opt for sports drinks on long runs
On longer runs (more than 90 minutes) it is definitely worth swapping water for an isotonic sports drink, which contains carbohydrate and electrolytes (salts that are lost through sweat) along with fluid. One study compared the effects of a sports drink and a placebo during a marathon and found that the runners who got the real thing were able to work at a higher heart rate, especially during the last 10 km of the race, when most people begin to slow down.
Studies have shown that there is a window of opportunity in the first half hour after a long run when glycogen stores are most receptive to being replenished - so this is the ideal time to have a carb-based snack. Aim for 1g of carbohydrate per kg of body weight, or simply opt for 50g. Research has shown that combining carbohydrate with protein in a ratio of 3: 1 optimises recovery. Try a banana with yoghurt and honey, or a chocolate milk drink.
Stick with the familiar
It's a good idea to stick to tried and tested meal options when you are fuelling up for important training sessions or races. Everyone is different, and there may be certain foods that your body doesn't handle well prior to running. Keeping a food diary can be helpful if you often experience gastrointestinal discomfort during running, to help determine what might trigger it. High fibre foods, wheat, sugar and caffeine are common culprits.